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.

5 Things to Know

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

How Antimicrobial Resistance Happens

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.

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.

Resistance Mechanisms (Defense Strategies)

Resistance Mechanisms (Defense Strategies)	Description
Restrict access of the antibiotic	Germs restrict access by changing the entryways or limiting the number of entryways.Example: Gram-negative bacteria have an outer layer (membrane) that protects them from their environment. These bacteria can use this membrane to selectively keep antibiotic drugs from entering.
Get rid of the antibiotic or antifungal	Germs get rid of antibiotics using pumps in their cell walls to remove antibiotic drugs that enter the cell.Example: Some Pseudomonas aeruginosa bacteria can produce pumps to get rid of several different important antibiotic drugs, including fluoroquinolones, beta-lactams, chloramphenicol, and trimethoprim. Example: Some Candida species produce pumps that get rid of azoles such as fluconazole.
Change or destroy the antibiotic	Germs change or destroy the antibiotics with enzymes, proteins that break down the drug.Example: Klebsiella pneumoniae bacteria produce enzymes called carbapenemases, which break down carbapenem drugs and most other beta-lactam drugs.
Change the targets for the antibiotic or antifungal	Many antibiotic drugs are designed to single out and destroy specific parts (or targets) of a bacterium. Germs change the antibiotic’s target so the drug can no longer fit and do its job.Example: Escherichia coli bacteria with the mcr-1 gene can add a compound to the outside of the cell wall so that the drug colistin cannot latch onto it. Example: Aspergillus fumigatus changes the cyp1A gene so that triazoles cannot bind to the protein.
Bypass the effects of the antibiotic	Germs develop new cell processes that avoid using the antibiotic’s target. Example: Some Staphylococcus aureus bacteria can bypass the drug effects of trimethoprim.

Disclosure: Most of this information was obtained from the CDC.gov  website and brought to you by

Dr. Yvette Fletcher-Prince, MD, DNP, APRN