Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes staph infections but is resistant to several common antibiotics, including methicillin and related drugs like penicillin. This resistance makes MRSA infections more difficult to treat and manage. Yes, a person can get MRSA twice; recurrence is a common challenge in managing this infection. Recurrence rates for MRSA skin and soft-tissue infections can be high, with estimates suggesting that as many as 70% of people who experience a community-acquired MRSA infection may see it return within a year.
Recurrence Is Common, Not Immunity
The human immune system does not typically develop a strong, lasting defense against MRSA, which is why repeat infections are frequent. Unlike viral illnesses, such as chickenpox, where a single infection usually leads to lifelong immunity, MRSA does not reliably trigger a durable protective response. MRSA is an opportunistic bacterium that primarily causes skin and soft-tissue infections, rather than systemic diseases that generate robust antibodies.
The body’s immune reaction to S. aureus is often inadequate to prevent future infections. Some research suggests that MRSA toxins can compromise the lymphatic system, which is crucial for immune function, potentially contributing to recurrence. Although some components of the immune system may offer a degree of protection, this response is often insufficient to fully clear the bacteria or prevent recolonization. The lack of effective immune memory means the body remains vulnerable even after successful initial treatment.
The Difference Between Relapse and Reinfection
Recurrence of MRSA occurs through two distinct mechanisms: relapse and reinfection. Distinguishing between them is important for effective long-term prevention. A relapse happens when the original infection was not completely eliminated, and the same strain of bacteria remains present in or on the body, leading to a flare-up. This is often linked to colonization, where the person carries MRSA without showing symptoms of an active infection.
Colonization occurs when MRSA bacteria reside on the skin or inside the nose, providing a reservoir from which a new infection can emerge, particularly when there is a break in the skin barrier. In contrast, reinfection is the acquisition of a completely new MRSA strain from an external source, such as another person or a contaminated surface. For example, a person might contract a new strain of MRSA from a shared environment or from close contact with a household member who is a carrier. Both relapse and reinfection contribute to the overall challenge of recurrence.
Factors That Increase the Risk of Recolonization
Specific conditions increase the likelihood that an individual will become a long-term carrier of MRSA after an infection has been treated. Prior or current colonization is the strongest predictor for developing another active infection. For example, the presence of MRSA in the nasal passages is a known risk factor, as the bacteria can live there for extended periods, sometimes for over a year.
Chronic health issues and medical interventions also create vulnerabilities for persistent colonization. High-risk individuals include those with diabetes, those on dialysis, or individuals with chronic wounds. The use of invasive medical devices, such as intravenous or urinary catheters, provides surfaces for bacteria to colonize and potential entry points into the body.
Recent or frequent use of broad-spectrum antibiotics can disrupt the body’s natural balance of bacteria, potentially promoting MRSA colonization by eliminating competing microorganisms. Close-contact environments and shared living spaces also play a significant role in recolonization and reinfection. Crowding, contact sports, and sharing personal items facilitate the spread of the bacteria. Household members who are colonized can act as a reservoir, leading to repeated infections.
Strategies to Reduce the Likelihood of Future Infections
Preventing future MRSA infections focuses on minimizing the bacterial reservoir and blocking transmission pathways. Strict personal hygiene practices are a foundational defense, including frequent and thorough handwashing, especially after touching wounds or being in public spaces. Proper wound management is also important, involving keeping all cuts, scrapes, and sores clean and covered until fully healed.
For individuals who have experienced a MRSA infection, a healthcare provider may recommend a clinical decolonization regimen to eradicate the carrier state. This procedure typically involves the application of a topical antibiotic ointment, such as mupirocin, to the nasal passages for a short period. This is often combined with daily use of a specialized antiseptic body wash, like chlorhexidine, for bathing. Environmental cleaning is another step, particularly disinfecting high-touch surfaces and avoiding the sharing of personal items to reduce the risk of reinfection.