Antibiotics are medicines that fight bacterial infections. Used properly, they can save lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and resist the effects of an antibiotic. Resistant bacteria may continue to grow and multiply.

Each time you take antibiotics there is a risk that the bacteria will become resistant. Resistant infections can be difficult and sometimes impossible to treat. They can spread to other people. Methicillin-resistant Staphylococcus aureus (MRSA) is one example. It causes infections that are resistant to several common antibiotics.

Antibiotic resistance can cause problems. To help prevent antibiotic resistance:

• Don't use antibiotics for viruses like colds or flu. Antibiotics don't work on viruses.
• Don't ask your health care provider to give you an antibiotic.
• When you take antibiotics, follow the directions carefully. Finish your medicine even if you feel better. If you stop treatment too soon, some bacteria may survive and re-infect you.
• Do not share your antibiotics with others.
• Don't save antibiotics for later or use someone else's prescription.

Antimicrobial resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them. That means the germs are not killed and continue to grow.

Antimicrobial resistance is an urgent global public health threat, killing at least 1.27 million people worldwide and associated with nearly 5 million deaths in 2019. In the U.S., more than 2.8 million antimicrobial-resistant infections occur each year. More than 35,000 people die as a result, according to CDC’s 2019 Antibiotic Resistance (AR) Threats Report. When Clostridioides difficile—a bacterium that is not typically resistant but can cause deadly diarrhea and is associated with antimicrobial use—is added to these, the U.S. toll of all the threats in the report exceeds 3 million infections and 48,000 deaths.

Antimicrobial resistance has the potential to affect people at any stage of life, as well as the healthcare, veterinary, and agriculture industries. This makes it one of the world’s most urgent public health problems.

Bacteria and fungi do not have to be resistant to every antibiotic or antifungal to be dangerous. Resistance to even one antibiotic can mean serious problems. For example:

• Antimicrobial-resistant infections that require the use of second- and third-line treatments can harm patients by causing serious side effects, such as organ failure, and prolong care and recovery, sometimes for months
• Many medical advances are dependent on the ability to fight infections using antibiotics, including joint replacements, organ transplants, cancer therapy, and the treatment of chronic diseases like diabetes, asthma, and rheumatoid arthritis
• In some cases, these infections have no treatment options

If antibiotics and antifungals lose their effectiveness, then we lose the ability to treat infections and control these public health threats.

Antibiotics are drugs that fight infections caused by bacteria NOT viruses. Antibiotics are not effective against viral infections like the common cold, most sore throats, and the flu. Taking antibiotics for viral infections will NOT:

• Cure the infection
• Keep other people from catching it
• Help you feel better
• Make you get back to work faster

Using antibiotics for viruses can put you at risk of getting a bacterial infection that is resistant to antibiotic treatment. Today, almost all important bacterial infections in the United States and throughout the world are becoming resistant to antibiotics. Antibiotic resistance has been called one of the world's most pressing public health problems.

Antibiotics are powerful drugs, but they are not the cure for all that ails you. The smart use of antibiotics is the key to controlling the spread of resistance.

FDA has teamed up with the Centers for Disease Control and Prevention (CDC) and other health care professional, government, academic, international and industry partners as part of a joint effort to raise awareness about the appropriate use of antibiotics

Antimicrobial resistance occurs when germs defeat the drugs designed to kill them, called antibiotics or antifungals. It does NOT mean your body is resistant to antibiotics or antifungals.

Antimicrobial resistance can affect people at any stage of life. Infections caused by resistant germs are difficult—sometimes impossible—to treat. In many cases, these infections require extended hospital stays, additional follow-up doctor visits, and the use of treatments that may be costly and potentially toxic.

You can take steps to reduce your risk of getting an infection. For example, healthy habits can protect you from infections and help stop germs from spreading. Get recommended vaccines, keep hands and wounds clean, and take good care of chronic conditions, like diabetes.

Talk to your healthcare provider or veterinarian about whether antibiotics or antifungals are needed. Antibiotics and antifungals do not work on viruses, such as colds and the flu. These drugs save lives. But, anytime they are used, they can lead to side effects and antimicrobial resistance. If you have been taking these drugs , tell your doctor if you have three or more diarrhea episodes in 24 hours.

Tell your healthcare provider if you recently traveled to or received care in another country. Antimicrobial resistance has been found in all regions of the world. Modern trade and travel mean it can move easily across borders, and can spread in places like hospitals, farms, the community, and the environment.

What are bacteria?

Bacteria and fungi are germs found inside and outside of our bodies. Most germs are harmless, and some can even be helpful to humans, but some can cause infections, like strep throat and urinary tract infections.

What is an antibiotic?

Antibiotics are critical tools for preventing and treating infections caused by specific bacteria in people, animals, and crops. In health care, antibiotics are one of our most powerful drugs for fighting life-threatening bacterial infections.

What is antibiotic resistance?

Antibiotic resistance happens when the germs no longer respond to the antibiotics designed to kill them. That means the germs are not killed and continue to grow. It does not mean our body is resistant to antibiotics.

Bacteria and fungi are constantly finding new ways to avoid the effects of the antibiotics used to treat the infections they cause.

Infections caused by antibiotic-resistant germs are difficult, and sometimes impossible, to treat. In many cases, antibiotic-resistant infections require extended hospital stays, additional follow-up doctor visits, and costly and toxic alternatives.

How can taking antibiotics contribute to antibiotic resistance?

Anytime antibiotics are used, they can contribute to antibiotic resistance. This is because increases in antibiotic resistance are driven by a combination of germs exposed to antibiotics, and the spread of those germs and their mechanisms of resistance. When antibiotics are needed, the benefits usually outweigh the risks of antibiotic resistance. However, too many antibiotics are being used unnecessarily and misused, which threatens the usefulness of these important drugs.

For example, too many antibiotics are being prescribed unnecessarily to humans in the United States. CDC estimates about 47 million antibiotic courses are prescribed for infections that don’t need antibiotics, like for colds and the flu, in U.S. doctors’ offices and emergency departments each year. That’s about 28% of all antibiotics prescribed in these settings.

Everyone has a role to play in improving antibiotic use. Appropriate antibiotic use helps fight antibiotic resistance and ensures these lifesaving drugs will be available for future generations.

Why should I care about antibiotic resistance?

Antibiotic resistance can affect any person, at any stage of life. People receiving health care or those with weakened immune systems are often at higher risk for getting an infection.

Antibiotic resistance jeopardizes advancements in modern health care that we have come to rely on, such as joint replacements, organ transplants, and cancer therapy. These procedures have a significant risk of infection, and patients won’t be able to receive them if effective antibiotics are not available.

Aside from healthcare, antibiotic resistance also impacts veterinary and agriculture industries.

How can I protect myself and my family from antibiotic resistance?

No one can completely avoid getting an infection, but there are additional steps you can take to protect yourself and your family.

Protect yourself and your family from antibiotic resistance by

• doing your best to stay healthy and keep others healthy,
• cleaning hands,
• covering coughs,
• staying home when sick, and
• getting recommended vaccines, such as the flu vaccine.

Taking antibiotics only when they are needed is an important way you can protect yourself and your family from antibiotic resistance. Talk to your doctor about the best treatment if you are sick. Never pressure your doctor to prescribe an antibiotic.

When antibiotics aren’t needed, they won’t help you, and their side effects could still cause harm. Ask your doctor or pharmacist about steps you can take to feel better when an antibiotic isn’t needed.

If your doctor decides an antibiotic is the best treatment when you are sick:

• Take the antibiotic exactly as your doctor tells you.
• Do not share your antibiotic with others.

• Do not save them for later. Talk to your pharmacist about safely discarding leftover medicines.
• Do not take antibiotics prescribed for someone else. This may delay the best treatment for you, make you even sicker, or cause side effects.
• Talk with your doctor and pharmacist if you have any questions about your antibiotics.

Antimicrobial resistance is a naturally occurring process. However, increases in antimicrobial resistance are driven by a combination of germs exposed to antibiotics and antifungals, and the spread of those germs and their resistance mechanisms.

Definition of Germs & Antimicrobials

Antimicrobial resistance does not mean our body is resistant to antibiotics or antifungals. It means the bacteria or fungi causing the infection are resistant to the antibiotic or antifungal treatment.

• Germs are microbes—very small living organisms including bacteria, fungi, parasites, and viruses.
• Most germs are harmless and even helpful to people, but some can cause infections. Harmful germs are called pathogens.
• Antimicrobials is a term used to describe drugs that treat many types of infections by killing or slowing the growth of pathogens causing the infection. The content on this webpage does not include resistance to antivirals or antiparasitics.
• Bacteria cause infections such as strep throat, foodborne illnesses, and other serious infections. Antibiotics treat bacterial infections.
• Fungi cause infections like athlete’s foot, yeast infections, and other serious infections. Antifungals treat fungal infections.
• People sometimes use “antibiotic” and “antimicrobial” interchangeably.

Patients should always be promptly treated with antibiotics when the drugs are needed for infections and to treat sepsis.

How Antibiotic and Antifungal Use Affects Resistance

Antibiotics and antifungals save lives, but their use can contribute to the development of resistant germs. Antimicrobial resistance is accelerated when the presence of antibiotics and antifungals pressure bacteria and fungi to adapt.

Antibiotics and antifungals kill some germs that cause infections, but they also kill helpful germs that protect our body from infection. The antimicrobial-resistant germs survive and multiply. These surviving germs have resistance traits in their DNA that can spread to other germs.

Spread of Germs & Resistance Mechanisms

To survive, germs can develop defense strategies against antibiotics and antifungals called resistance mechanisms. DNA tells the germ how to make specific proteins, which determine the germ’s resistance mechanisms. Bacteria and fungi can carry genes for many types of resistance.

When already hard-to-treat germs have the right combination of resistance mechanisms, it can make all antibiotics or antifungals ineffective, resulting in untreatable infections. Alarmingly, antimicrobial-resistant germs can share their resistance mechanisms with other germs that have not been exposed to antibiotics or antifungals.

This table gives a few examples of defense strategies used to resist the effects of antibiotics or antifungals.

Resistant germs can spread between people, animals, and the environment, and can cause deadly infections. Stopping spread is a key action to protect people and slow development of antimicrobial resistance, along with preventing infections in the first place and improving antibiotic and antifungal use.

Learn more about five areas resistance emerges and spreads.

Healthcare Facilities

Germs can cause infections in patients receiving care for something else.

Your Community

Germs can make people sick through common activities.

Water & Soil

Antimicrobial resistance can develop and spread in the environment.

Food Supply

Germs can get into the food supply and make people sick.

Around the World

Resistance can emerge and spread with remarkable speed between continents.

People receiving medical care in healthcare facilities like hospitals or nursing homes can get serious infections called healthcare-associated infections (HAIs). People can get HAIs during or after procedures like surgery, or from devices like catheters or ventilators. Sometimes these infections can be caused by antimicrobial-resistant germs. People can also enter healthcare facilities with infections from the community or from another healthcare facility when transferred and these germs could spread without appropriate infection control measures.

Some of the deadliest resistant germs spread within and across healthcare facilities. In fact, seven urgent or serious antimicrobial-resistant threats identified in CDC’s 2019 AR Threats Report can cause HAIs. The estimated national cost to treat infections caused by these six multidrug-resistant germs can be substantial—more than $4.6 billion annually.

Yet many HAIs are preventable. From 2012 to 2017, the number of antimicrobial-resistant infections seen in hospitals dropped 27% and the number of deaths from antimicrobial-resistant infections fell nearly 30%. Although progress has been made, more work is needed. Three critical efforts to prevent an HAI and slow the spread of resistance include:

• Prevent infections related to surgery or placement of a catheter
• Prevent the spread of germs through infection prevention and control
• Improve use of antibiotics and antifungals (these drugs save lives but their use can contribute to the development of resistant germs)

How Germs Can Spread in Healthcare Facilities

Healthcare staff use infection control practices like hand hygiene or wearing protective equipment to prevent spreading germs. Without appropriate infection control actions, germs can:

• Enter the body and cause infections through procedures and medical devices (e.g., catheters)
• Spread to people on surfaces like bedrails or the hands of healthcare workers
• Move with patients when they are transferred from one healthcare facility to another, or into the community when patients go home
• When not stopped, these resistant healthcare-associated germs can spill over into communities, becoming much harder to control

Germs can also spread in other ways. Fecal waste (poop) can carry traces of previously consumed antibiotics, antifungals, and antimicrobial-resistant germs. The combination of these drugs and resistant germs in hospital wastewater allows these resistant germs to survive in plumbing systems (e.g., toilets).

Additionally, when waste goes to treatment plants, there is the possibility of sewage leaks and overflow along the way, and sometimes drug residues and resistant germs are released as part of the treated wastewater. This can contribute to antimicrobial resistance in the environment, including contaminating lakes and streams. CDC and partners are doing more research to better understand the spread of resistance through water.

COVID-19 Impacts Antimicrobial Resistance

Much of the U.S. progress in combating antimicrobial resistance was lost in 2020, in large part, due to the effects of the COVID-19 pandemic. The pandemic pushed healthcare facilities, health departments, and communities near their breaking points.

About Antibiotic/Antifungal Use in Healthcare

Antibiotics and antifungals are valuable tools. Patients should always be promptly treated when the drugs are needed for infections and to prevent sepsis. Effective antibiotics and antifungals are also needed for people who are at high risk for developing infections, such as patients who have surgery and are at risk for surgical site infections.

However, any antibiotic and antifungals use—for people, animals, or plants—can cause side effects and contribute to antimicrobial resistance. One life-threatening side effect of taking antibiotics is severe diarrhea and colitis (inflammation of the colon) caused by Clostridioides difficile (also called C. diff). In 2017, CDC estimated 223,900 cases of C. diff infections requiring hospitalizations or in already hospitalized patients. At least 12,800 people died. C. diff can spread rapidly within healthcare facilities.

Improving antibiotic and antifungal prescribing and use is critical to treat infections effectively, protect patients from harms, and combat antimicrobial resistance.

Germs are part of everyday life. Many germs do not cause harm and some even help us stay healthy. Only a small portion of germs are known to cause infection. Unfortunately, there have been rising antimicrobial-resistant infections in U.S. communities.

CDC is concerned about antimicrobial-resistant germs in the community for several reasons.

• Community-associated infections can happen to healthy people who have not had a recent interaction with health care (healthcare-associated germs tend to impact sicker, more vulnerable people while they receive care)
• Infections in the community can be difficult to identify and control spread
• New forms of resistance can emerge and spread quickly, especially resistance shared among germs through mobile genetic elements
• Antimicrobial-resistant germs can share their resistance genes with other germs, making them more difficult to treat

We can slow the spread of resistant threats in the community using simple interventions, such as good hygiene, routine vaccination, safer sex practices, and safe food preparation. Many of these interventions have already proven successful. Learn more about steps everyone can take to reduce your risk of getting an infection.

How Germs Can Spread in Community

Germs, including resistant germs, can spread between people, animals, and food, through common activities. For example, germs can spread from food to people and between people and animals without appropriate hand hygiene. People can also get an infection when traveling, then spread these germs when they return. Other examples include gonorrhea, a common sexually transmitted disease (STD) that has progressively developed resistance to almost every drug ever used to treat it. Infections associated with drug-resistant gonorrhea and group A Streptococcus, the most common cause of sore throat, have both increased since 2000.

About Antibiotic/Antifungal Use in Communities

Antibiotics and antifungals are valuable tools. However, any use — for people, animals, or plants—can cause side effects and contribute to antimicrobial resistance.

In U.S. outpatient doctors’ offices and emergency departments, at least 28% of antibiotic courses prescribed each year are unnecessary. In U.S. outpatient doctors’ offices specifically, 1 out of every 3 antibiotic drugs prescribed is unnecessary. That’s 47 million unnecessary prescriptions, each of which carries the potential for side effects, allergic reactions and Clostridioides difficile infections, which can cause deadly diarrhea.

In the community, reactions from antibiotics often require emergency treatment. In fact, reactions from antibiotics cause 1 out of 5 medication-related visits to the ER. In children, reactions from antibiotics are the most common cause of medication-related ER visits.

Misuse or mismanagement of antibiotics and antifungals can also contribute to resistanceantibiotic resistance, antibiotics, drug resistance, drug resistant, antibiotic resistant, bacteria, bacterial infection, infections, mrsa, Methicillin-resistant Staphylococcus aureus, viruses, colds, flu, fungi, germs, drugs, medicine, Clostridioides difficile, healthcare, antifungal, drug resistances, microbial, antimicrobial drug resistance, antimicrobial drug resistances, bacterial, beta lactam resistance, chloramphenicol resistance, kanamycin resistance, tetracycline resistance, trimethoprim resistance, vancomycin resistance, fungal, viral, pharmacological, public health, overuse, misuse, . For example, people with tuberculosis (TB)—a disease caused by bacteria that are spread from person to person through the air—can die if they do not get proper treatment. Drug-resistant TB can occur when the drugs used to treat TB are misused or mismanaged.

Clinicians should prescribe their patients antibiotics and antifungals only when the benefits outweigh the potential risks. Veterinarians can also help improve antibiotic or antifungal use when prescribing these drugs. Improving prescribing and use is critical to effectively treat infections, protect patients from harms, and combat antimicrobial resistance.

COVID-19 Impacts Antimicrobial Resistance

Much of the U.S. progress in combating antimicrobial resistance was lost in 2020, in large part, due to the effects of the COVID-19 pandemic. The pandemic pushed healthcare facilities, health departments, and communities near their breaking points.

Human activity can contaminate the environment (water, soil) with antibiotics and antifungals, which can speed up the development and spread of resistance. Contamination can occur from:

• Human and animal waste
• Use of antibiotics and antifungals as pesticides on plants or crops
• Pharmaceutical manufacturing waste

Scientific evidence from a report called Initiatives for Addressing Antimicrobial Resistance in the Environment show that traces of antibiotics and antifungals, germs resistant to them, and genes that cause resistance traits are present and can spread in waterways and soils. However, scientists do not fully understand the risk of resistance in the environment on human health.

Measuring the relationship between resistant germs and genes, drug residues (small amounts of leftover drugs or pieces of drugs that are not completely absorbed by the body), the environment, and human health is complex and incomplete. CDC and partners are doing innovative research to better understand the spread of resistance in the environment and the impact on human health.

How Germs Can Spread in the Environment & About Antibiotic/Antifungal Use

Human Waste

Fecal waste (poop) can carry traces of previously consumed antibiotics, antifungals, and antimicrobial-resistant germs. This waste and wastewater can contribute to the development and spread of antimicrobial-resistant germs in the environment, and possibly have a negative impact on human health.

Wastewater treatment plants (WWTPs) reduce contaminants in wastewater before discharging the treated water into waterways. However, some antibiotic and antifungal residues and resistant germs and genes can survive treatment because wastewater treatment systems are not specifically designed to kill or remove them.

Studies have found measurable levels of resistant bacteria in surface waters (rivers, coastal waters) because of sewage leaks, overflow, or release of untreated or undertreated wastewater discharge. This caused illness in some people who were exposed to these germs through contaminated water.

The presence of antimicrobial-resistant germs in human waste is especially challenging for wastewater from inpatient healthcare facilities like hospitals. Patients at healthcare facilities can shed some of the deadliest germs from resistant infections and are commonly prescribed antibiotics and antifungals.

Water and sanitation systems, and the degree to which they prevent or spread resistance, varies greatly throughout the world and between communities. Many countries face challenges in providing adequate sanitation—the ability to dispose of human waste safely and maintain hygienic conditions.

Globally, most human waste is discharged directly into the environment without treatment. This includes open defecation and discarding untreated waste into waterways. Advancements in sanitation systems and improving antibiotic and antifungal use will help slow the development of resistance.

Animal Waste

Antibiotics and antifungals are sometimes given to food animals to treat, control, and prevent diseases. Like human waste, manure from food-producing animals treated with antibiotics and antifungals can carry drug residues and resistant germs. This could contaminate the surrounding soil and nearby water sources. Animal waste is often used as fertilizer on agricultural lands to help with plant growth. While more research is needed, using untreated or un-composted animal manure that contains residues or resistant germs as fertilizer can contribute to the development and spread of resistant germs through the environment.

Pesticides

Various diseases can infect plants and crops (e.g., wheat, oranges, corn). These diseases can be difficult to control and extremely damaging because they can impact farm income and the food supply. Antibiotics and antifungals (fungicides) are sometimes applied as pesticides to manage plant and crop diseases. However, using antibiotics and fungicides in agriculture can contribute to resistance in the environment by contaminating soil and water. For example, stormwater and irrigation water from farmland can contaminate nearby bodies of water with resistant germs and antibiotic or antifungal residues.

This contamination can affect human health when the pesticides are the same as, or closely related to, antibiotics and antifungals used in human medicine. For example, triazoles are the most widely used fungicides on plants and crops, but are also similar to important human antifungal medicines used to prevent or treat fungal infections caused by germs like Aspergillus fumigatus. Patients with azole-resistant A. fumigatus infections are up to 33% more likely to die than patients with infections that can be treated with azoles. Use of triazole fungicides in the environment increased more than four times from 2006 to 2016 in the U.S. alone. Appropriate use of azoles in human medicine and agriculture can help combat resistance.

Aquaculture

Antibiotics and antifungals are used worldwide in aquaculture (the farming of fish and seafood) to control disease. Using antibiotics and antifungals in aquaculture can contaminate the local aquatic environment with these drugs and residues. There are limited data on antibiotic and antifungal use in aquaculture and its impacts on human health.

Drinking Water

Safe water is water that is clean to drink, accessible when needed, and free from germs and chemicals. Globally, access to safe water and basic sanitation can reduce the spread of resistant germs in the environment and between people, causing fewer waterborne infections and the need for antibiotics and antifungals.

Worldwide, in 2017, 780 million people did not have access to at least basic water services. Additionally, more than 2 billion people lacked access to basic sanitation (more than 25% of the world’s population). The World Health Organization estimates that if everyone had access to improved drinking water and sanitation, diarrheal illnesses that are treated with antibiotics would be reduced by 60%.

The U.S. food supply is among the safest in the world, but people can still get sick from foodborne infections or from contact with animals and their environments. CDC estimates that each year 48 million people get sick from a foodborne illness. These infections can be caused by antimicrobial-resistant bacteria. Germs like Campylobacter, Salmonella, and Shigella cause an estimated 742,000 antimicrobial-resistant infections each year. The number of drugs these germs are resistant to seems to be increasing.

How Germs Can Spread to People from the Food Supply

Animals, like people, carry germs in their gut, which can include antimicrobial-resistant germs. These germs can spread between animals and in their environments (such as on farms, in animal markets, and during transport). When animals are slaughtered and processed for food, these germs can contaminate meat or other animal products.

Animal waste can also carry antimicrobial-resistant germs. Fruits, vegetables, and other produce can become contaminated through contact with soil or water containing untreated or un-composted waste from animals.

People can get infections from food in different ways:

• From handling or eating meat, seafood, milk, or eggs that are raw or undercooked and contaminated with resistant germs
• From handling or eating fruits and vegetables contaminated with resistant germs
• From contact with untreated or un-composted animal waste, either directly or when it gets into water and the environment
• From touching or caring for animals without proper handwashing

Additionally, antibiotics and antifungals are sometimes applied as pesticides to manage plants and crop disease.

About Antibiotic/Antifungal Use in the Food Supply

Antibiotics and antifungals are valuable tools. However, any use—for people, animals, or plants—can cause side effects and contribute to antimicrobial resistance. Most of the time, antibiotics and antifungals are not needed to treat foodborne illnesses. Avoiding unnecessary use helps slow the spread of antimicrobial resistance. However, some people may get more severe infections and antibiotics and antifungals can be lifesaving. People at risk for severe infections include young children, pregnant women, older adults, and people with other health conditions. Talk with your healthcare provider and learn more about antibiotic use and human health.

Antibiotic and antifungals use in food animals can help treat, control, and prevent bacterial diseases in animals. However, to slow the spread of antimicrobial resistance, these drugs should only be used when necessary. CDC supports judicious use of antibiotics and antifungals in people and animals, including the important work that the U.S. Food and Drug Administration (FDA) and U.S. Department of Agriculture (USDA) are doing to improve antibiotic use in veterinary medicine and agriculture. Learn how livestock and poultry producers can help stop the spread of antimicrobial resistance.

Protect Yourself: 4 Steps for Food Safety

• Clean hands, cooking utensils, and surfaces when preparing food

• Separate raw meat from other foods

• Cook foods to safe temperatures

• Chill leftovers and other foods promptly

• Learn more about food safety tips and other actions to protect yourself and family from resistance

FDA’s 2015 Veterinary Feed Directive (VFD) final rule outlines the process for authorizing the use of VFD drugs (animal drugs intended for use in or on animal feed that require the supervision of a licensed veterinarian) and provides veterinarians in all states with a framework for authorizing the use of medically important antibiotics—those that are important to human health—in feed when needed for specific animal health purposes.

Additionally, implementation of FDA’s Guidance for Industry #213 in 2017 significantly changed the way medically important antibiotics can be used in food animals. When the changes were fully implemented, it became illegal to use medically important antibiotics for production purposes, and animal producers now need to obtain authorization from a licensed veterinarian to use them for treatment, prevention, and control of a specifically identified disease. Learn how veterinarians protect patients and people from antimicrobial resistance.

USDA, with FDA and the Environmental Protection Agency (EPA), administers the U.S. National Residue Program (NRP) to prevent residues that pose a potential threat to human health from entering the food supply.

Understanding Food Labels

USDA requires documentation from food producers to approve labels. Food labels on meat and poultry like “No Antibiotics Ever (NAE)” or “Raised Without Antibiotics,” and “No Added Antibiotics” mean that source food animals never received antibiotics. When these labels accompany a seal that states “USDA Process Verified,” it means USDA inspectors visited the farm to verify antibiotic use.

However, these products can still carry antimicrobial-resistant bacteria. All animals carry bacteria in their gut, and some of these can be resistant, even if the animal never receives antibiotics. These resistant bacteria can spread between animals and into food products.

Antimicrobial resistance has been identified in all regions of the world and can rapidly spread. The amount of resistance and number of infections is different worldwide, along with the use of antibiotics and antifungals, access to clean water and adequate sanitation, vaccination coverage, and access to quality healthcare.

There are considerable knowledge gaps regarding how much antimicrobial resistance occurs globally. This is especially seen in low- and middle-income countries lacking laboratories to test for resistance and systems to collect infection data.

Antimicrobial resistance is an urgent global public health threat, killing at least 1.27 million people worldwide and associated with nearly 5 million deaths in 2019. In the U.S., more than 2.8 million antimicrobial-resistant infections occur each year. Germs will inevitably find ways to resist antibiotics and antifungals, which is why aggressive action is needed now to keep new resistance from developing and to prevent the resistance that already exists from spreading.

How Germs Can Spread

Germs can spread within healthcare facilities, communities, our food supply, and the environment. Modern travel of people, animals, and goods means resistance can easily spread. One billion people cross through international borders each year. This includes 350 million travelers arriving in the U.S. through more than 300 points of entry.

The capacity and resources for infection prevention and control vary worldwide. A resistant threat somewhere can quickly become a threat anywhere. When infection prevention and control capacity is strengthened in a country, the world benefits. Global efforts can contribute to solutions that protect people from this threat, including:

• Improve quality and consistency of infection control nationwide
• Detect and respond to resistance early, containing it before it becomes common
• Enhance and develop products that improve hygiene, prevent infections, and keep germs from spreading
• Increase education and awareness around infection prevention and control

About Global Antibiotic/Antifungal Use

An important driver of resistance is antibiotic and antifungal use. Antibiotics and antifungals are valuable tools. People should always be promptly treated when the drugs are needed for infections and to prevent sepsis. However, any use—for people, animals, or plants—can cause side effects and lead to antimicrobial resistance.

In the U.S., 5 out of 6 people are prescribed an antibiotic each year—at least 30% of this antibiotic use is unnecessary. According to the Center for Disease Dynamics, Economics & Policy’s (CDDEP) 2021 global analysis of antibiotic resistance, global antibiotic consumption in humans increased by 65% between 2000 and 2015, whereas consumption in animals is expected to increase by 11.5% between 2017 and 2030. If nothing changes, antibiotic consumption is likely to increase worldwide by 200% between 2015 and 2030.

Globally, the use of antibiotics and antifungals are increasing, particularly in low- and middle-income countries as antibiotics and antifungals become more accessible and affordable. Yet some parts of the world cannot access antibiotics and antifungals when they need them, putting patients at risk. While some vaccines are available, low vaccination coverage, coupled with poor water, sanitation, and hygiene infrastructure, leaves many people vulnerable to infection and dependent on antibiotics for treatment.

Everyone should have access to antibiotics and antifungals that work when they are needed. Every country should work to reduce unnecessary use of these drugs; improve access; implement and measure stewardship programs; and track use and use the data to advance solutions.

The American food supply is among the safest in the world, but people can still get food poisoning by eating contaminated foods. Some food poisoning is caused by antibiotic-resistant bacteria. Symptoms of infection with antibiotic-resistant bacteria are like other food poisoning symptoms, which can be mild to life-threatening and include diarrhea, nausea, and vomiting.

Antibiotics are medicines that kill or stop the growth of bacteria. Antibiotic resistance happens when bacteria develop the ability to survive or grow despite being exposed to antibiotics designed to kill them.

Antibiotics save lives, but any time antibiotics are used, they can contribute to the development and spread of antibiotic resistance. Antibiotic resistance spreads to bacteria through people, animals, and the environment. Improving antibiotic use, including reducing unnecessary use, can help stop resistance from spreading.

Learn what CDC is doing to help stop antibiotic-resistant infections from food and animals, and how you can protect yourself and your family.

Antibiotic Resistance and Food Poisoning

If bacteria that cause food poisoning are antibiotic resistant, some antibiotics might not effectively treat the illness, which can lead to more costly treatments and higher risks for side effects.

People with symptoms of mild food poisoning usually do not need antibiotics to get better. However, people with severe infection may need to see a doctor, take antibiotics, or be hospitalized.

Mild symptoms may include nausea, diarrhea, and vomiting.

Severe symptoms include:

• Bloody diarrhea
• High fever (temperature over 102°F, measured by mouth)
• Frequent vomiting that prevents keeping liquids down (which can lead to dehydration)
• Signs of dehydration, including little or no urination, a very dry mouth and throat, or feeling dizzy when standing up
• Diarrhea that lasts more than 3 days

Who Is at Higher Risk for Food Poisoning

Those at higher risk include adults aged 65 and older, children younger than 5 years, people who have health problems or take medicines that lower the body’s ability to fight germs and sickness, and pregnant women. These groups are at risk for severe symptoms or complications from food poisoning, including illnesses caused by antibiotic resistant bacteria.

Food and Food Animals

Animals, like people, carry bacteria in their guts. Antibiotic-resistant bacteria present in the guts of animals can get in food in several ways:

• When animals are slaughtered and processed for food, resistant bacteria can contaminate meat or other animal products.
• Animal feces/excrement (poop) can contain resistant bacteria and get into the surrounding environment.
• Fruits and vegetables can get contaminated through contact with soil, water, or fertilizer that contains animal feces/excrement.

Transmission of Antibiotic-Resistant Intestinal Infections to People

People can get antibiotic-resistant intestinal infections by handling or eating contaminated food or coming in contact with animal waste (poop), either through direct contact with animals and animal environments or through contaminated drinking or swimming water. Infections can also spread between people.

In recent years, CDC has investigated many multistate outbreaks caused by antibiotic-resistant bacteria. These outbreaks have been linked to contaminated food and contact with farm animals, pets, and pet food and treats.

Protect Yourself and Your Family

• When preparing food, follow the four steps to food safety:
  • Clean. Wash your hands before and after touching uncooked eggs or raw meat, poultry (like chicken and turkey), seafood, or their juices. Wash your work surfaces, cutting boards, utensils, and dishes before, during, and after cooking.
  • Separate. Germs from raw meat, poultry, seafood, and eggs can spread to fruits, vegetables, and other ready-to-eat foods unless you keep them separate. Use one cutting board to prepare raw meats and another for foods that will not be cooked before they’re eaten. Don’t put cooked meat on a plate that had raw meat on it.
  • Cook. Use a food thermometer to ensure that foods are cooked to a safe internal temperature: 145°F for whole cuts of beef, pork, lamb, and veal (such as steaks, chops, and roasts); 160°F for ground red meats and egg dishes; and 165°F for poultry, including ground chicken and turkey. Get safe cooking temperaturesexternal icon for other foods.
  • Chill. Keep your refrigerator at 40°F or below and refrigerate foods within 2 hours of cooking. Refrigerate within 1 hour if food is exposed to temperatures above 90°F (like a hot car or picnic).
• When around pets and other animals:
  • Wash your hands after touching them, their food, water, poop, belongings (such as toys and bowls), or habitats (such as beds, cages, tanks, coops, stalls, and barns).
  • Report suspected illness from food to your local health department.
  • Review CDC’s Travelers’ Health recommendations when preparing for international travel.

To help slow the spread of antibiotic resistance, take antibiotics only when needed, and take them exactly as prescribed by your healthcare provider.

The National Institute of Allergy and Infectious Diseases (NIAID) is supporting research on several organisms that have developed resistance to antimicrobial drug treatment.

The institute manages a research portfolio of grants aimed at the problem of antimicrobial resistance and hospital-acquired infections. Here is a list of some of the leading antimicrobial drug-resistant organisms NIAID is researching.

Mycobacterium tuberculosis

The bacterium that causes tuberculosis (TB)
TB is an often severe airborne disease caused by a bacterial infection. TB typically affects the lungs, but it also may affect many other organs of the body. It is usually treated with a regimen of several drugs taken for six months to two years, depending on the type of infection. In most cases, TB is treatable. However, some bacteria are becoming resistant to the two most potent TB drugs. This is known as multi-drug-resistant TB (MDR TB).

C. difficile

(Clostridium difficile)
C. difficile is a pathogen infecting the colon of patients following antibiotic treatment. The communities of microbes that normally live in the gut usually prevent C. difficile colonization and suppress C. difficile-associated disease. Antibiotic treatment can alter the microbiota that allows C. difficile, a bacterium that is naturally resistant to many common antibiotics, to grow and cause inflammation in the colon. C. difficile is a major health care-associated infection in the U.S., causing mild to severe diarrhea. Around half a million people are infected each year, resulting in approximately 15,000 deaths.

VRE

(Vancomycin-resistant Enterococci)
Enterococci are bacteria that are commonly found colonizing the human digestive tract and female genital tract. VRE infections tend to occur in people who are in hospitals or other health care facilities. They also often occur in people who are susceptible to infection due to other medical problems or the presence of certain catheters or other devices. Health care providers commonly use the antibiotic vancomycin to treat Enterococcal infections, but VRE are resistant to the drug.

MRSA

(Methicillin-resistant Staphylococcus aureus)
During the past four decades, methicillin-resistant Staphylococcus aureus, or MRSA, has evolved from a controllable nuisance into a serious public health concern. MRSA is one of the most common hospital-acquired infections. Increasingly, however, strains are circulating in the community and can cause severe infections.

Neisseria gonorrhoea

The bacterium that causes gonorrhea
Gonorrhea is a sexually transmitted infection and the second most commonly reported infection in the U.S. It can cause severe reproductive complications if left untreated, and it disproportionately affects sexual, racial, and ethnic minorities. Gonorrhea control relies on prompt identification and treatment of infected persons and their sex partners. Because some drugs are becoming less effective in treating gonorrhea, the CDC recently updated its treatment guidelines to slow the emergence of drug resistance. Gonorrhea is a global problem. Action in the U.S. alone is unlikely to prevent resistance from developing, but rapid detection and effective treatment of patients and their partners might slow the spread of resistance.

CRE

(Carbapenem-resistant Enterobacteriaceae)
CRE is a family of highly resistant bacteria that includes Klebsiella species and Escherichia coli (E. coli). CRE primarily affect patients in hospitals and those who have compromised immune systems. The bacteria can enter the body through medical devices like ventilators or catheters. Some CRE infections are resistant to most available antibiotics and can be life-threatening.

A number of pathogens are increasingly resistant to existing antibiotics and antifungals. NIAID is researching infections of growing concern to human health, including pathogens identified by the Centers for Disease Control and Prevention (CDC) as urgent, serious, and concerning threats.

Gram-Negative Bacteria

The Gram stain test, developed in the 1800s by Hans Christian Gram, is a method for classifying different types of bacteria using a chemical stain and viewing through a microscope the results on the bacteria’s protective cell wall. Most bacteria are classified into two groups—gram-positive or gram-negative—depending on whether they retain a specific stain color. Gram-positive bacteria retain a purple-colored stain, while Gram-negative bacteria appear pinkish or red. Gram-negative bacteria have a double membrane that cannot be penetrated by many antibiotics. Types of Gram-negative bacteria include:

Carbapenem-resistant Enterobacteriaceae (CRE)

Enterobacteriaceae, such as Klebsiella pneumoniae and Escherichia coli (E. coli) can cause serious infections of the urinary tract, bloodstream and wounds, and can also cause pneumonia. These infections are becoming difficult to treat because some bacteria have become resistant to all or most available antibiotics. Some Enterobacteriaceae contain an enzyme called extended-spectrum β-lactamase (ESBL) which makes them resistant to nearly all penicillins and cephalosporins. Other Enterobacteriaceae can be resistant to carbapenems, which are considered drugs of last resort. Enterobacteriaceae-related disease usually occurs in patients at healthcare facilities who have weak immune systems, are on breathing machines or use urinary or intravenous catheters. The bacteria can enter the body through these devices or through wounds from surgery or injury. However, some people can have Enterobacteriaceae in their body without it causing any disease.

Drug-resistant Neisseria gonorrhoeae (N. gonorrhoeae)

N. gonorrhoeae bacteria causes gonorrhea, a sexually-transmitted infection that, if left untreated, can cause serious problems such as pelvic inflammatory disease, infertility and long-term pelvic or abdominal pain. Not all infections are drug-resistant, but N. gonorrhoeae has developed resistance to nearly all the antibiotics used for treatment, making it harder to cure.

Multidrug-resistant Acinetobacter

Infection with Acinetobacter (including Acinetobacter baumanii) bacteria can cause serious bloodstream and wound infections and pneumonia. Infections typically occur in patients in healthcare settings and intensive care units who have weakened immune systems, chronic lung disease, open wounds, or are on a breathing machine or catheter. Some people have Acinetobacter bacteria in their body but do not become infected or show symptoms. However, at least three different classes of antibiotics can no longer cure resistant Acinetobacter infections.

Multidrug-resistant Pseudomonas aeruginosa (P. aeruginosa)

P. aeruginosa bacteria can cause mild illness in healthy people, such as ear infections and skin rashes after exposure to inadequately cleaned hot tubs or pools. However, serious P. aeruginosa-associated bloodstream infections and pneumonia can occur in hospitalized patients with weakened immune systems, including people who have wounds from surgery or are using breathing machines or catheters. Infections can spread among patients via the hands of healthcare workers or equipment that is not properly cleaned. Some strains of P. aeruginosa are resistant to most or all antibiotics, including aminoglycosides, cephalosporins, fluoroquinolones and carbapenems.

Drug-resistant Salmonella

Salmonella bacteria can cause diarrhea, fever and abdominal cramps in people who consume contaminated food (raw or undercooked meat or eggs) or water. Some infections, such as those resistant to certain classes of drugs, can be more severe, spread to the blood and cause life-threatening complications. A serotype called Salmonella Typhi causes typhoid fever when people consume food or water contaminated with feces. Typhoid fever, uncommon in the U.S., can cause abdominal pain, headache, fever, bowel perforation, shock and death.

Drug-resistant Shigella

Shigella bacteria is found in the stool of infected humans. Shigella infection (shigellosis) can cause diarrhea, fever and abdominal pain. It is transmitted when people touch a surface that has been contaminated (including even tiny amounts of fecal matter that are too small to see) and then touch their mouths. It can also be transmitted by eating contaminated food, swallowing lake or river water or through exposure to feces through sexual contact. Resistance to the first-line antibiotics used to treat Shigella is widespread, so physicians must rely on alternatives (ciprofloxacin and azithromycin). However, resistance to the alternatives also is growing.

Other pathogens of concern:

Clostridioides difficile (C. difficile or C. diff)

C. diff bacteria can cause mild to severe life-threatening diarrhea, most commonly in people who have recently taken antibiotics. C. diff is shed in feces and transmitted via spores that are present when someone touches a contaminated surface and then touches his or her mouth. Normally the microbes that live in the gut (called gut microbiota) can suppress C. diff-associated disease, but antibiotic treatment can deplete the microbiota in such a way that allows C. diff spores to germinate into vegetative cells which can produce up to three different toxins, causing extreme colonic inflammation. People at higher risk of infection include patients in healthcare settings who have recently taken antibiotics and older adults. C. diff is not yet significantly resistant to the drugs used to treat it, but these drugs are sometimes ineffective and can also leave the person vulnerable to disease recurrence. Moreover, the global burden of C. diff is driven by antibiotic use and the spread of microbes, the same factors that propel antibiotic resistance.

Drug-resistant Candida

Candida is a yeast (type of fungus) that lives in the human mouth, throat, gut and vagina and usually does not cause problems. However, it can cause infections and varying symptoms if people have a weakened immune system or are taking antibiotics. Infection can occur in the mouth and throat (called thrush), esophagus or vagina. Candida can also cause serious invasive infections of the bloodstream (called candidemia), heart, brain, eyes and bones, most commonly in hospitalized patients. Some strains of Candida are becoming resistant to antifungal drugs, including fluconazole. The strain Candida auris is extremely rare but of increasing concern in the U.S. and can be resistant to all three types of antifungal medications.

Drug-resistant Campylobacter

People usually become infected with Campylobacter (including Campylobacter jejuni) bacteria by eating raw or undercooked poultry or drinking unpasteurized milk. Infection can cause diarrhea, cramping, abdominal pain, fever and can become life-threatening if spread to the bloodstream. The bacteria is becoming resistant to antibiotics (ciprofloxacin and azithromycin), which can cause longer, more severe infections as well as post-infectious problems such as gastrointestinal, neurological and joint disorders.

Vancomycin-resistant Enterococcus (VRE)

Enterococcus bacteria are commonly found in the human digestive and female genital tracts but do not pose a threat to healthy people. However, Enterococcus can cause urinary tract infections, bloodstream infections and wound infections in hospitalized patients. Infections typically occur in patients who have previously been treated with antibiotics for extended periods of time, have undergone surgery, have catheters, or have weakened immune systems. Infection can be deadly as about one-third of Enterococcus infections are resistant to the last-resort antibiotic vancomycin.

Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Staphylococcus aureus (VRSA)

S. aureus bacteria are a leading cause of healthcare-associated infections in the U.S. Some people carry the bacteria in their noses and it does not cause infection. However, it can cause skin infections and pneumonia in the general community and severe illness in hospitalized patients, including bloodstream, heart valve and surgical site infections, and pneumonia. Patients in healthcare settings who have weakened immune systems, have been treated with antibiotics, have wounds from surgery or have a breathing device or catheter are most at risk for severe infection. The bacteria can spread among patients from unclean hands of healthcare workers or visitors or when patients come in direct contact with contaminated bed linens and medical equipment. In addition to being resistant to methicillin and related antibiotics, a small number of S. aureus infections are also resistant to vancomycin, the drug most commonly used to treat serious S. aureus, leaving few to no treatment options.

Drug-resistant tuberculosis (TB)

TB is an airborne disease that typically infects the lungs but can attack any other organ of the body. TB is generally treated with a course of antibiotics that can last months to years. However, Mycobacterium tuberculosis, the bacteria that causes TB disease, is becoming resistant to the antibiotics commonly used to treat it. Multidrug-resistant TB (MDR-TB) refers to infections caused by bacteria resistant to isoniazid and rifampin, the two most potent TB drugs. Extensively drug-resistant TB (XDR-TB) refers to infections caused by bacteria that are resistant to isoniazid and rifampin, any fluoroquinolone and at least one of three injectable second-line drugs. People with drug-resistant TB face a higher risk of death and infections can be costly and time-consuming to treat.

Drug-resistant Streptococcus pneumoniae

S. pneumoniae can cause pneumococcal disease, which includes pneumonia, ear infections, sinus infections, meningitis and bloodstream infections. Some infections can become invasive, leading to hospitalization and potentially death. S. pneumoniae has developed resistance to commonly used antibiotics such as amoxicillin and azithromycin and is developing resistance to other drugs.

Erythromycin-resistant Group A Streptococcus

Group A Streptococcus bacteria can cause a range of disease such as strep throat, scarlet fever, impetigo, toxic shock syndrome, rheumatic fever and necrotizing fasciitis (“flesh-eating” disease). It is transmitted when an infected person coughs or sneezes and passes water droplets that touch another person’s nose or mouth. Group A Streptococcus can still be treated with the first-line drug penicillin, but the bacteria is developing resistance to clindamycin (the drug commonly used to treat severe, life-threatening infections) and macrolides, including erythromycin.

Clindamycin-resistant Group B Streptococcus

Group B Streptococcus bacteria can cause severe illness such as bloodstream infections, pneumonia, meningitis and skin infections. However, it is usually harmless in healthy adults and people can carry group B Streptococcus in their bodies without having symptoms. The bacterium is also a leading cause of severe infections in infants. If a pregnant woman tests positive for group B Streptococcus, physicians will prescribe her antibiotics during labor to prevent the spread of the bacteria to the baby. Group B Streptococcus can be treated with penicillin, but it is developing resistance to the recommended second-line drugs clindamycin and erythromycin.

Gonorrhea has progressively developed resistance to the antibiotic drugs prescribed to treat it. Following the spread of gonococcal fluoroquinolone resistance, the cephalosporin antibiotics have been the foundation of recommended treatment for gonorrhea. The emergence of cephalosporin-resistant gonorrhea would significantly complicate the ability of providers to treat gonorrhea successfully, since we have few antibiotic options left that are simple, well-studied, well-tolerated and highly effective. It is critical to continuously monitor antibiotic resistance in Neisseria gonorrhoeae and encourage research and development of new treatment regimens.

Efforts to prevent antibiotic resistance build on the foundation of proven public health strategies. Use this page to learn how you can protect both you and your family from antibiotic-resistant infections.

Healthy Habits

Clean Your Hands

Cleaning your hands is like a “do-it-yourself” vaccine you can take to reduce the spread of diarrheal and respiratory illness so you can stay healthy. Regular hand cleaning, particularly before and after certain activities, is one of the best ways to remove germs, avoid getting sick, and prevent the spread of germs to others.

Stay Up-to-Date with Vaccines

Disease prevention is key to staying healthy. It is always better to prevent a disease than to treat it. Vaccines can protect both the people who receive them and those with whom they come in contact. Vaccines are responsible for the control of many infectious diseases that were once common in this country and around the world, including polio, measles, diphtheria, pertussis (whooping cough), rubella (German measles), mumps, tetanus, and Haemophilus influenza type b (Hib). Over the years vaccines have prevented countless cases of infectious diseases and saved millions of lives.

Prevent the Spread of Food borne Infections

Following these simple steps will help keep your family safer from food poisoning at home.

Keep Your Water Safe

Keeping your water safe and how you use your water can prevent infections from occurring.

Prevent the Spread of Sexually Transmitted Diseases

Take control and learn effective strategies to reduce STD risk. Know the facts and protect yourself and your partner.

Staying safe when sick

Use Antibiotics the Right Way

Are you aware that colds, flu, most sore throats, and bronchitis are caused by viruses? Did you know that antibiotics do not help fight viruses? It’s true. Plus, taking antibiotics when you have a virus may do more harm than good. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

Learn When Respiratory Illnesses Need Antibiotics

Antibiotics aren’t always the answer for common respiratory infections. Antibiotics do not fight infections caused by viruses like colds, most sore throats and bronchitis, and some ear infections. Unneeded antibiotics may lead to future antibiotic-resistant infections. Symptom relief might be the best treatment option.

Feel Better with Symptom Relief

Children and adults with viral infections, which antibiotics cannot treat, usually recover when the illness has run its course. Colds, a type of viral infection, can last for up to two weeks. You should keep your healthcare provider informed if your or your child’s illness gets worse or lasts longer than expected. Over-the-counter medicines may help relieve some symptoms.

Staying safe while in a hospital

Be a Safe Patient

Hospitals remain a source of many of the most resistant organisms, but there are several ways to protect yourself or a loved one. Don’t be afraid to ask your healthcare provider to clean their hands.

Antibiotics are drugs used for treating infections caused by bacteria. Also known as antimicrobial drugs, antibiotics have saved countless lives.

Misuse and overuse of these drugs, however, have contributed to a phenomenon known as antibiotic resistance. This resistance develops when potentially harmful bacteria change in a way that reduces or eliminates the effectiveness of antibiotics.

A Public Health Issue

Antibiotic resistance is a growing public health concern worldwide. When a person is infected with an antibiotic-resistant bacterium, not only is treatment of that patient more difficult, but the antibiotic-resistant bacterium may spread to other people.

When antibiotics don't work, the result can be

• longer illnesses
• more complicated illnesses
• more doctor visits
• the use of stronger and more expensive drugs
• more deaths caused by bacterial infections

Examples of the types of bacteria that have become resistant to antibiotics include the species that cause skin infections, meningitis, sexually transmitted diseases and respiratory tract infections such as pneumonia.

In cooperation with other government agencies, the Food and Drug Administration (FDA) has launched several initiatives to address antibiotic resistance.

The agency has issued drug labeling regulations, emphasizing the prudent use of antibiotics. The regulations encourage health care professionals to prescribe antibiotics only when clinically necessary, and to counsel patients about the proper use of such drugs and the importance of taking them as directed. FDA has also encouraged the development of new drugs, vaccines, and improved tests for infectious diseases.

Antibiotics Fight Bacteria, Not Viruses

Antibiotics are meant to be used against bacterial infections. For example, they are used to treat strep throat, which is caused by streptococcal bacteria, and skin infections caused by staphylococcal bacteria.

Although antibiotics kill bacteria, they are not effective against viruses. Therefore, they will not be effective against viral infections such as colds, most coughs, many types of sore throat, and influenza (flu).

Using antibiotics against viral infections

• will not cure the infection
• will not keep other individuals from catching the virus
• will not help a person feel better
• may cause unnecessary, harmful side effects
• may contribute to the development of antibiotic-resistant bacteria

Patients and health care professionals alike can play an important role in combating antibiotic resistance. Patients should not demand antibiotics when a health care professional says the drugs are not needed. Health care professionals should prescribe antibiotics only for infections they believe to be caused by bacteria.

As a patient, your best approach is to ask your health care professional whether an antibiotic is likely to be effective for your condition. Also, ask what else you can do to relieve your symptoms.

So how do you know if you have a bad cold or a bacterial infection?

Joseph Toerner, M.D., MPH, a medical officer in FDA’s Center for Drug Evaluation and Research, says that the symptoms of a cold or flu generally lessen over the course of a week. But if you have a fever and other symptoms that persist and worsen with the passage of days, you may have a bacterial infection and should consult your health care provider.

Follow Directions for Proper Use

When you are prescribed an antibiotic to treat a bacterial infection, it's important to take the medication exactly as directed. Here are more tips to promote proper use of antibiotics.

• Take the antibiotics as prescribed. It's important to take the medication as prescribed by your doctor, even if you are feeling better. If treatment stops too soon, and you become sick again, the remaining bacteria may become resistant to the antibiotic that you've taken.
• Do not skip doses. Antibiotics are most effective when they are taken as prescribed.
• Do not save antibiotics. You might think that you can save an antibiotic for the next time you get sick, but an antibiotic is meant for your particular infection at the time. Never take leftover medicine. Taking the wrong medicine can delay getting the appropriate treatment and may allow your condition to worsen.
• Do not take antibiotics prescribed for someone else. These may not be appropriate for your illness, may delay correct treatment, and may allow your condition to worsen.
• Talk with your health care professional. Ask questions, especially if you are uncertain about when an antibiotic is appropriate or how to take it.
• All drugs have side effects. Let your health care professional know if you have new or unusual symptoms or side effects. You might need to stop the antibiotic causing a troublesome side effect and complete treatment with a different antibiotic.

Consumers and health care professionals can also report adverse events to FDA's MedWatch program at 800-FDA-1088 or online at MedWatch.

What FDA Is Doing

FDA combating antibiotic resistance through activities that include

• Approval of certain new antibiotics. Since 2015, FDA approved new antibiotics that can treat certain resistant bacteria. Health care professional are encouraged to use the new antibiotics appropriately and for some antibiotics, use only in patients who have limited or no other treatment options.
• Labeling regulations addressing proper use of antibiotics. Antibiotic labeling contains required statements in several places advising health care professionals that these drugs should be used only to treat infections that are believed to be caused by bacteria. Labeling also encourages health care professionals to counsel patients about proper use.
• Partnering to promote public awareness. FDA is partnering with the Centers for Disease Control and Prevention (CDC) on "Get Smart: Know When Antibiotics Work," a campaign that offers Web pages, brochures, fact sheets, and other information sources aimed at helping the public learn about preventing antibiotic-resistant infections.
• Encouraging the development of new antibiotics. FDA developed guidances for industry on the types of clinical studies that could be performed to evaluate how an antibacterial drug works for the treatment of different types of infections. FDA organized and participated in workshops aimed to address the development of new antibiotics that treat resistant bacterial infections.

For nearly a century, bacteria-fighting drugs known as antibiotics have helped to control and destroy many of the harmful bacteria that can make us sick. But in recent decades, antibiotics have been losing their punch against some types of bacteria. In fact, certain bacteria are now unbeatable with today’s medicines. Sadly, the way we’ve been using antibiotics is helping to create new drug-resistant “superbugs.”

Superbugs are strains of bacteria that are resistant to several types of antibiotics. Each year these drug-resistant bacteria infect more than 2 million people nationwide and kill at least 23,000, according to the U.S. Centers for Disease Control and Prevention (CDC). Drug-resistant forms of tuberculosis, gonorrhea, and staph infections are just a few of the dangers we now face.

Antibiotics are among the most commonly prescribed drugs for people. They’re also given to livestock to prevent disease and promote growth. Antibiotics are effective against bacterial infections, such as strep throat and some types of pneumonia, diarrheal diseases, and ear infections. But these drugs don’t work at all against viruses, such as those that cause colds or flu.

Unfortunately, many antibiotics prescribed to people and to animals are unnecessary. And the overuse and misuse of antibiotics helps to create drug-resistant bacteria.

Here’s how that might happen. When used properly, antibiotics can help destroy disease-causing bacteria. But if you take an antibiotic when you have a viral infection like the flu, the drug won’t affect the viruses making you sick. Instead, it’ll destroy a wide variety of bacteria in your body, including some of the “good” bacteria that help you digest food, fight infection, and stay healthy. Bacteria that are tough enough to survive the drug will have a chance to grow and quickly multiply. These drug-resistant strains may even spread to other people.

Over time, if more and more people take antibiotics when not necessary, drug-resistant bacteria can continue to thrive and spread. They may even share their drug-resistant traits with other bacteria. Drugs may become less effective or not work at all against certain disease-causing bacteria.

“Bacterial infections that were treatable for decades are no longer responding to antibiotics, even the newer ones,” says Dr. Dennis Dixon, an NIH expert in bacterial and fungal diseases. Scientists have been trying to keep ahead of newly emerging drug-resistant bacteria by developing new drugs, but it’s a tough task.

“We need to make the best use of the drugs we have, as there aren’t many in the antibiotic development pipeline,” says Dr. Jane Knisely, who oversees studies of drug-resistant bacteria at NIH. “It’s important to understand the best way to use these drugs to increase their effectiveness and decrease the chances of resistance to emerge.”

You can help slow the spread of drug-resistant bacteria by taking antibiotics properly and only when needed. Don’t insist on an antibiotic if your health care provider advises otherwise. For example, many parents expect doctors to prescribe antibiotics for a child’s ear infection. But experts recommend delaying for a time in certain situations, as many ear infections get better without antibiotics.

NIH researchers have been looking at whether antibiotics are effective for treating certain conditions in the first place. One recent study showed that antibiotics may be less effective than previously thought for treating a common type of sinus infection. This kind of research can help prevent the misuse and overuse of antibiotics.

“Treating infections with antibiotics is something we want to preserve for generations to come, so we shouldn’t misuse them,” says Dr. Julie Segre, a senior investigator at NIH.

In the past, some of the most dangerous superbugs have been confined to health care settings. That’s because people who are sick or in a weakened state are more susceptible to picking up infections. But superbug infections aren’t limited to hospitals. Some strains are out in the community and anyone, even healthy people, can become infected.

One common superbug increasingly seen outside hospitals is methicillin-resistant Staphylococcus aureus (MRSA). These bacteria don’t respond to methicillin and related antibiotics. MRSA can cause skin infections and, in more serious cases, pneumonia or bloodstream infections.

A MRSA skin infection can appear as one or more pimples or boils that are swollen, painful, or hot to the touch. The infection can spread through even a tiny cut or scrape that comes into contact with these bacteria. Many people recover from MRSA infections, but some cases can be life-threatening. The CDC estimates that more than 80,000 aggressive MRSA infections and 11,000 related deaths occur each year in the United States.

When antibiotics are needed, doctors usually prescribe a mild one before trying something more aggressive like vancomycin. Such newer antibiotics can be more toxic and more expensive than older ones. Eventually, bacteria will develop resistance to even the new drugs. In recent years, some superbugs, such as vancomycin-resistant Enterococci bacteria, remain unaffected by even this antibiotic of last resort.

“We rely on antibiotics to deliver modern health care,” Segre says. But with the rise of drug-resistant bacteria, “we’re running out of new antibiotics to treat bacterial infections,” and some of the more potent ones aren’t working as well.

Ideally, doctors would be able to quickly identify the right antibiotic to treat a particular infection. But labs need days or even weeks to test and identify the bacteria strain. Until the lab results come in, antibiotic treatment is often an educated guess.

“We need to know how to treat for a favorable outcome, but knowledge about the infection can be several days away,” explains Dr. Vance Fowler, an infectious disease expert at Duke University School of Medicine.

Fowler says faster diagnostic testing offers one of the best hopes for treating infectious diseases. Technology is catching up, he says, and new research in this area looks promising.

Genetic studies by NIH-supported researchers such as Segre and Fowler are also helping us understand the unique characteristics of antibiotic-resistant bacteria. Their findings could point the way to innovative new treatments.

While scientists search for ways to beat back these stubborn bacteria, you can help by preventing the spread of germs so we depend less on antibiotics in the first place.

The best way to prevent bacterial infections is by washing your hands frequently with soap and water. It’s also a good idea not to share personal items such as towels or razors. And use antibiotics only as directed. We can all do our part to fight drug-resistant bacteria.

Blocking Harmful Bacteria

• Wash your hands often with soap and water, or use an alcohol-based hand sanitizer.
• If you’re sick, make sure your doctor has a clear understanding of your symptoms. Discuss whether an antibiotic or a different type of treatment is appropriate for your illness.
• If antibiotics are needed, take the full course exactly as directed. Don’t save the medicine for a future illness, and don’t share with others.
• Maintain a healthy lifestyle—including proper diet, exercise, and good hygiene—to help prevent illness, thereby helping to prevent the overuse or misuse of medications.

Some of the bacteria that cause infections in humans have become resistant to the antibiotics we use to combat them. Antibiotic resistance can turn once-manageable infections into "superbug" diseases that are difficult—and sometimes impossible—to treat. According to the Centers for Disease Control and Prevention, in the United States alone, at least 2 million people each year develop serious infections with drug-resistant bacteria, and about 23,000 die.

Scientists funded by the National Institutes of Health are studying many aspects of antibiotic resistance, including how it spreads. Here are just a few examples of what they're exploring and how it could aid efforts to curb the emergence of resistance.

Detecting New Sources of Antibiotic Resistance

The most common way that bacteria become invulnerable to antibiotics is through the transfer of resistance genes from other bacteria. Often, these genes are found on small, circular pieces of DNA called plasmids that are readily passed among bacterial species.

David Cummings of Point Loma Nazarene University in San Diego searches for plasmids bearing resistance genes in sediment samples from several urban wetlands. These habitats provide ideal conditions for bacteria from diverse sources, such as human sewage, animal waste and naturally occurring plant and soil microorganisms, to swap genes and spread antibiotic resistance, he notes.

So far, Cummings has found that during winter rains, the coastal wetlands in San Diego receive runoff containing antibiotic-resistant bacteria and plasmids, which can persist in the wetlands at low levels into the dry summer months. Some of these plasmids contain genes that confer resistance to commonly used antibiotics, including beta-lactam drugs like penicillin and cephalosporins and fluoroquinolones like ciprofloxacin (Cipro).

By better understanding the nature of drug resistance plasmids in urban wetlands, Cummings hopes to aid future efforts to prevent their potential spread among bacteria that cause human disease. It remains to be seen whether drug-defying bacterial genes that accumulate in the wetlands are likely to move into other species of harmful bacteria and then to us.

Checking the Gut to Head off Resistance

Bacteria living in the human body can trade resistance genes, too. Gautam Dantas of Washington University School of Medicine in St. Louis is investigating how resistance develops in and spreads among the bacteria that colonize the human gut during the first 2 years of life.

As soon as babies emerge from the womb, they start picking up microbes from their moms, their caregivers and the environment. The human intestinal tract, in particular, harbors hundreds of microbial species, many of which are harmless or even beneficial to their hosts.

"The first 2 or 3 years of life are when the real action occurs in terms of setting up the network of microbes in the human gut," says Dantas. But taking antibiotics can promote the emergence of drug-resistant strains of bacteria by favoring the proliferation of "bugs" that can evade the drugs. And kids from birth to age 5 are given more antibiotics per capita than any other age group, he adds.

Dantas is studying the development of the complete collection of resistance genes in the gut—dubbed the resistome—in healthy sets of twins and in infants with very low birthweights. By cataloging the abundance and diversity of these genes in fecal samples taken from infants at regular intervals and looking at how they change over time, he hopes to gain insights on how the gut resistome is affected by antibiotic treatment, genetics and other factors.

"This is a way to detect resistance genes before they [transfer into disease-causing bacteria and] become a problem," says Dantas. His work also could lead to a more informed strategy for antibiotic use in kids to minimize the risk that bad bugs will survive and multiply.

Modeling the Spread and Control of Resistance

Staphylococcus aureus (staph) bacteria often coexist peaceably with humans, hanging out on body surfaces like the nose or skin without ill effects. Roughly a third of the general population is harmlessly colonized with this form of staph bacteria, and most people don't develop an active infection.

In the past decade, though, certain virulent, antibiotic-resistant strains of staph, known as methicillin-resistant Staphylococcus aureus, or MRSA, have spread rampantly in the general community. These so-called community-associated MRSA (CA-MRSA) infections have become the most common cause of skin infections seen in hospital emergency departments and can turn deadly if they spread to the bloodstream or internal organs, says Diane Lauderdale of the University of Chicago.

To understand how patterns of contact and behavior among individuals affect the spread of CA-MRSA, Lauderdale and Charles Macal of Argonne National Laboratory developed a computer model representing the real-world interactions of the Chicago metropolitan area population in households, schools, workplaces, gyms, hospitals, prisons and other settings. The scientists fine-tuned the model to simulate retrospectively the actual spread of CA-MRSA that occurred in the city from 2001 to 2011.

The model revealed that more than 90 percent of CA-MRSA infections were due to contact with a colonized, symptom-free individual. It also indicated that households were by far the most common site of infection, followed by schools. These findings, Lauderdale says, point the way to strategies that are most likely to curb the spread of drug-resistant staph in the community, such as disinfectant treatments targeting affected households, which the researchers can then test using their virtual version of the Windy City.

Over-prescribed and misused, these wonder drugs are leading to widespread drug resistance

For the past 70 years, antimicrobial drugs, such as antibiotics, have successfully treated patients with infections. But over time, many infectious organisms have adapted to the drugs that kill them, making them less effective. Overusing or misusing these drugs can make resistance develop even faster.

Each year in the U.S. at least 2 million people become infected with bacteria that are resistant to antibiotics. At least 23,000 people die annually as a direct result of these infections. Many more people die from complications of antibiotic-resistant infections.

To address this growing problem, the National Institute of Allergy and Infectious Diseases (NIAID) is working to speed the development of faster ways to detect resistance and ultimately to find new treatments that are effective against these drug-resistant bacteria.

"If you are given antibiotics, you will kill all the sensitive bacteria. Most of the ones that will survive will be the resistant ones."

- Anthony S. Fauci, M.D.

Drug-Resistant Bacteria: On the Edge of a Crisis

Anthony S. Fauci, M.D., has been the director of the National Institute of Allergy and Infectious Diseases (NIAID) since 1984. He helped pioneer the field of human immunoregulation, or the control of specific immune responses and interactions. He has also advised five presidents and the U.S. Department of Health and Human Services on HIV/AIDS and many other health issues. He spoke to NIH MedlinePlus magazine to discuss NIAID's drug-resistant bacteria research program.

Why are certain bacteria becoming more resistant to drugs?

There is a multi-part answer to that question. One of the most important reasons is that bacteria generally mutate—all microbes mutate—naturally and spontaneously. However, you can do things that pressure them to mutate even more and develop resistance to drugs.

One of the major factors in certain bacteria becoming resistant to drugs today is the overuse of antibiotics, particularly the inappropriate use of antibiotics. This includes using antibiotics when you do not really have to—either when you have a viral infection that you think is bacterial and treat it with an antibiotic, or you treat someone with the wrong antibiotic that is not particularly suited to the bacteria in question.

In other words, if you are given antibiotics, you will kill all the sensitive bacteria. Most of the ones that will survive will be the resistant ones.

You and other experts in the field have said that we are on the edge of a national, even global crisis of drug-resistant bacteria. Why is that?

The more we see this growing problem of antimicrobial resistance throughout the world, the more we will begin to see bacteria that are relatively untreatable or very, very difficult to treat. And if those bacteria become very widespread, that could lead to a serious crisis.

What might such a situation look like to most people?

A typical, real-life example would be someone gets a surgical procedure like a hip or knee replacement, or goes to the hospital for abdominal surgery. Then they get an infection that happens to come from another hospital patient who has resistant bacteria. What should be a routine procedure could lead to an infection that you struggle to treat, and you end up with a high degree of morbidity or even mortality. The routine surgical case becomes a medical emergency.

What kinds of antimicrobial-resistant bacteria are common in the U.S.?

We still have the problem of methicillin-resistant Staphylococcus aureus (MRSA), which is disturbing. Another one that is also disturbing is called Carbapenem-resistant Enterobacteriaceae, or CRE. That is a growing problem. We see that in hospital patients who are immunosuppressed as a result of, for example, transplants or drugs that suppress their cancer or their inflammatory disease. Another bacteria that causes infections when antibiotics are overused is Clostridium difficile (C. Difficile), which we see a lot of in nursing homes and hospital settings.

Those three are big ones—MRSA, CRE, and C. Difficile. And, depending on the population in question, globally we are seeing more and more resistance to gonorrhea, a sexually transmitted disease.

How is NIAID approaching research to help solve the challenges associated with antimicrobial resistance?

Our research spans a wide range of activities, starting with understanding the molecular basis of how bacterial resistance evolves.

The second thing we are doing is a molecular analysis of microbes to determine what the targets are for resistance and for new antibiotics. Another is to develop new, unique ways of combating bacteria, such as understanding how microbes survive in different environments and exploiting that to fight them.

We also spend a lot of time working with the pharmaceutical companies on concept development towards the ultimate development of new antibiotics. While new antibiotics will ultimately be made by pharmaceutical companies, NIH and NIAID have a basic, fundamental role in the clinical and applied research and development of these new antibiotics.

Chart of common conditions and whether or not antibiotics are needed

• Strep throat: Caused by bacteria. Antibiotic needed.
• Whooping cough: Caused by bacteria. Antibiotic needed.
• Urinary tract infection: Commonly caused by bacteria. Antibiotic needed.
• Sinus infection: Commonly caused by bacteria or a virus. Antibiotic may be needed.
• Middle ear infection: Commonly caused by bacteria or a virus. Antibiotic may be needed.
• Bronchitis/chest cold (in otherwise healthy children and adults)*: Commonly caused by bacteria or a virus. Antibiotic not needed.
• Common cold/runny nose: Caused by a virus. Antibiotic not needed.
• Sore throat (except strep): Commonly caused by a virus. Antibiotic not needed.
• Flu: Caused by a virus. Antibiotic not needed.

*Studies show that in otherwise healthy children and adults, antibiotics for bronchitis won’t help you feel better.