Antibiotic-Resistant Bacteria: MRSA and C. diff

Janet Phoenix MD MPH, Amanda Bisnath, Megan Peterson, Elizabeth Sack

Since the discovery of the first antibiotic, penicillin, in 1928, antibiotics and antimicrobial drugs have been widely used in the United States. Over time, some bacteria have developed ways to survive these drugs. Unfortunately, the widespread use of antibiotics has contributed to the development of antibiotic-resistant bacteria.

What Causes Antibiotic Resistance?

When a person takes an antibiotic, the drug kills bacteria, but a few can survive. These surviving bacteria are resistant to that antibiotic. They then multiply. This means that every time a patient takes an antibiotic, he or she is creating more drug-resistant bacteria. Although bacterial antibiotic resistance is an evolutionary process, societal factors also contribute to the problem. The inappropriate use of antibiotics (such as using them to treat viral infections like colds) contributes to the growing number of antibiotic-resistant bacteria today. For years, antibiotics have been prescribed for colds, earaches, flu, and other infections that normally clear up on their own. Inappropriate use of antibiotics, such as not taking doses as prescribed or taking antibiotics for viral infections, can also contribute to the emergence of antibiotic-resistant bacteria.

In recent years, antibacterial household products have become common in household cleaners, soaps, detergents, hand lotions, tooth brushes, and sometimes even plastic containers and mattresses. Although people buy these products with the intent of protecting their family from harmful germs, the widespread use of antibacterial products helps to produce resistant bacteria. As with antibiotic medications, it is important to be cautious when using these products.

Scientists are also concerned about the use of antibiotics in livestock.[1] Cows, chickens, and pigs were often fed low levels of antibiotics over long periods of time, and this was believed to promote the survival of antibacterial-resistant bacteria in livestock. Fortunately, these policies are changing. FDA specifies that antibiotics should be given to livestock only when a veterinarian prescribes them to treat ill animals or prevent disease in animals who are at risk of becoming ill.[2]  The latter restriction is very subjective and is considered a major loophole.  Antibiotic use anywhere contributes to resistance everywhere.

Large pharmaceutical companies have stopped developing antibiotics because they are less profitable than other drugs. Most new antibiotics are very similar to older ones, and resistance can develop quickly as a result.  Experts believe that it stewardship is essential, meaning that new antibiotics should be used only when absolutely necessary, to reduce resistance.  However, companies want to promote their new antibiotics to sell as many as possible, which also results in resistant bacteria. The World Health Organization reports that of the 50 antibiotics that are currently being developed, only two are active against multi-drug resistant bacteria.[5] This is of particular concern, since there are a number of multi-drug resistant bacteria, such as MRSA and c. diff that are increasingly becoming a serious public health problem in hospital and community settings.

What is MRSA?

Methicillin-resistant Staphylococcus aureus (MRSA) is commonly known as “staph.” Staph bacteria are frequently found on the nose or skin and are usually harmless. However, staph bacteria can cause severe infections if they enter the bloodstream.[6] MRSA is a type of staph that has a dangerous resistance to a family of antibiotics similar to penicillin. Approximately 2% of people carry MRSA.[6]

A MRSA infection normally starts as small bumps that resemble pimples or boils. They can be red, swollen, painful, or have pus or other drainage. Sometimes a MRSA infection is limited to the skin, but the bacteria can also cause infections in the bones, joints, surgical wounds, bloodstream, lungs, and heart valves.[7] Symptoms of a more serious infection could include fever, difficulty breathing, sweating, pallor, and rapid heart rate. If the valves of the heart are infected, symptoms may include chest pain or irregular heart beats. In some cases, excessive bleeding may occur.

How is MRSA Transmitted?

MRSA infections can be spread in hospital or community settings. In hospitals, MRSA spreads following exposure to the bacteria during medical care. Inserting a foreign material into the body during surgery or other procedure can introduce MRSA into the body. MRSA can also be transmitted through person-to-person contact, known as community-based infections. MRSA bacteria can enter the body through a cut, wound, or abrasion after coming in contact with an infected person or object. [6]

The U.S. Centers for Disease Control and Prevention (CDC) found that MRSA infections from hospitals have declined by 74% from 2005 to 2016. However, infections from community contact have risen by 3.9% since 2013.[8] The current opioid epidemic is a potential reason for this increase since MRSA infections from drug injections increased from 4.1% to 9.2% between 2011 and 2016.[9]

How is MRSA Treated?

Although MRSA is resistant to most drugs, it still responds to certain medications. Most doctors rely on intravenous vancomycin or other antibiotic drugs in its class (glycopeptide antibiotics) to treat resistant bacteria. Many less severe staph skin infections can be treated by draining any abscesses or boils. Additionally, applying prescribed antiseptics and creams to the site of infection can decrease the amount of bacteria in the body. This should only be done by a healthcare professional.

How Can I Prevent a MRSA Infection?

The best way to prevent MRSA infections is to practice good hygiene.[10] Washing hands frequently with soap and water is a great way to prevent an infection. Avoiding contact with other people’s wounds or bandages; limiting the share of personal items like towels, sheets, razors, and athletic equipment; and restricting the share of lip balms, lotions, or cosmetics are best practices to stop the spread of MRSA and other staph infections. In patients struggling with drug addiction, it is important to provide information on safe injection practices, wound care, and how to recognize signs of staph infection can curb the spread of bacteria.[10]

What is C. diff?

Clostridium difficile, commonly called c. diff, is a different type of bacteria that is resistant to some antibiotics and alcohol-based hand sanitizers. It is normally present in our digestive tracts, but is kept in check by other normally-occurring bacteria. Sometimes, general antibiotics can kill the bacteria that keep c. diff under control. When this happens, the number of c. diff bacteria grow and cause an infection that results in diarrhea, fever, and abdominal pain.[11] Due to this loss of good bacteria, people taking antibiotics are 7 to 10 times more likely to contract c. diff.[12]

How is C. diff Transmitted?

Although antibiotics are the most common cause of c. diff, the infection can also spread in hospital and community settings. In hospitals, c. diff is spread by touching unclean hospital surfaces or the hands of health care providers, especially if the providers are using hand sanitizer instead of soap and water to clean their hands. In the community, c. diff can spread through direct contact with an infected person.[13] Fortunately, most healthy adults who come in contact with c. diff are not likely to get sick. Eighty percent of infections occur in people older than 65 years of age.[12]

How Can I Treat C. diff?

About 20% of patients who contracted c. diff from antibiotic use will recover at the end of their antibiotic treatment.[11] Following treatment, healthy bacteria are restored to normal levels and are able to keep c. diff in check. For patients who do not recover or who contract c. diff from hospital or community contact, a course of strong antibiotics typically resolves the infection. Oral forms of vancomycin and fidaxomicin are often used to treat these c. diff infections.[11] Some medical professionals may even consider a fecal matter transplant, transferring bacteria from a healthy person’s stool, to treat c. diff. although this form of treatment is still considered investigational.[14] For more information about fecal matter transplants, click here.

How Can I Prevent C. diff?

Though treatments exist, the best way to avoid c. diff is to practice effective prevention measures. To prevent transmission in healthcare settings, make sure your doctor washes their hands with soap and water before and after seeing you.[15] Additionally, doctors should avoid prescribing antibiotics unless absolutely necessary. If you are prescribed antibiotics, take a probiotic or eat yogurt with active cultures to promote the growth of healthy bacteria.[16] To prevent transmission at home and in your community, wash your hands with soap and water every time you use the bathroom and before you eat. Cleaning commonly-touched surfaces with a mixture of bleach and water can kill c. diff bacteria in the home.[15]

Future Considerations: “Superbugs”

Although MRSA and c. diff can be effectively treated with some antibiotics, other types of bacteria are becoming antibiotic-resistant. These bacteria are commonly called “superbugs” due to their strength against antibiotics. A lack of treatment for new infections poses a serious and dangerous threat to public health.[17]

A 2019 CDC report listed the major antibiotic-resistant infections that have emerged in recent years. The report perceived five of these infections to be most dangerous because of their resistance to multiple drugs, their ability to spread quickly in a population, and the burdens they could place on healthcare personnel and infrastructure. They are Carbapenem-resistant Acinetobacter, Drug-resistant Candida auris, Clostridium difficile, Carbapenem-resistant Enterobacteriaceae, and Drug-resistant Neisseria gonorrhoeae.[18] Although reducing the use of antibiotics and maintaining proper hygiene can prevent these infections, there are currently no known reliable treatments.

The Bottom Line

The overuse of antibiotics has contributed to the increase of antibiotic-resistant infections. Though MRSA and c. diff can still be treated with antibiotics, newer “superbugs” are resisting even the newest forms of treatment. Reducing the use of antibiotics and practicing effective preventative measures, like frequent hand-washing and limiting the sharing of personal items, can help reduce the spread of antibiotic-resistant infections.




  1. Pew Charitable Trusts. FDA to Update Medically Important Animal Antibiotics List. May 27, 2020.
  2. Centers for Disease Control and Prevention. Food and Food Animals.,in%20animals%20that%20are%20sick&text=Prevent%20disease%20in%20animals%20that%20are%20at%20risk%20for%20becoming%20sick. Updated February 10, 2020.
  3. World Health Organization. 2019 Antibacterial Agents in Clinical Development: An Analysis of the Antibacterial Clinical Development Pipeline. 2019.
  4. ScienceDirect. Time for a change in how new antibiotics are reimbursed: Development of an insurance framework for funding new antibiotics based on a policy of risk mitigation. October 2017.
  5. World Health Organization. Lack of new antibiotics threatens global efforts to contain drug-resistant infections. January 17, 2020.
  6. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA) Healthcare Settings.,every%20100%20people%20carry%20MRSA. Updated February 28, 2019.
  7. National Institute for Occupational Safety and Health. MRSA and the Workplace.,can%20be%20treated%20without%20antibiotics. Updated August 17, 2015.
  8. Kourtis AP, Hatfield K, Baggs J, et al. Vital Signs: Epidemiology and Recent Trends in Methicillin-Resistant and in Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections — United States. MMWR Morb Mortal Wkly Rep 2019. 68: 214–219.
  9. Jackson KA, Bohm MK, Brooks JT, et al. Invasive Methicillin-Resistant Staphylococcus aureus Infections Among Persons Who Inject Drugs — Six Sites, 2005–2016. MMWR Morb Mortal Wkly Rep 2018. 67:625–628.
  10. Mayo Clinic. MRSA Infection – Symptoms & Causes. MayoClinic.come. October 18, 2018.
  11. Centers for Disease Control and Prevention. Clostridiodes difficile (C. diff), FAQs for Clinicians about C. diff. Updated March 27, 2020.
  12. Centers for Disease Control and Prevention. Clostridioides difficile (C. diff) What is C. diff?.
  13. Durovic A, Widmer AF, Tschudin-Sutter S. New insights into transmission of Clostridium difficile infection–narrative review. Clinical Microbiology and Infection. 2018; 24(5): 483-492.,-Actual%20transmission%20of&text=difficile%20occurs%20by%20the%20faecal,indirect%20contact)%20%5B49%5D.
  14. National Center for Health Research. Fecal Matter Transplants – What You Need to Know. 2020.
  15. Centers for Disease Control and Prevention. Clostridiodes difficile (C. diff), Prevent the Spread of C. diff.,and%20always%20before%20you%20eat. Reviewed November 4, 2019.
  16. Mills JP, Rao K, Young VB. Probiotics for Prevention of Clostridium difficile Infection. Current Opinions in Gastroenterology. 2018: 34(1): 3-10.,compounds%20that%20directly%20inhibit%20C.
  17. Pritish Tosh. What are superbugs and how can I protect myself from infection? Mayo Clinic. Updated March 20, 2020.
  18. Centers for Disease Control and Prevention. Antibiotic Resistance Threats in the United States. 2019.