Question:

I had a splinter in my foot a year ago that caused a small pus pocket in the skin. I took out the splinter and the skin healed. Recently my elbow got red and swollen. I went to the hospital. It was a Methicillin-resistant Staph aureus (MRSA) infection, treated with an effective antibiotic. Can I assume it is gone, or once you have had MRSA does it always stay in your body?

Answer:

When penicillin was discovered in the 1940s, virtually all strains of Staph aureus were vulnerable to the new antibiotic. But within a decade, bacterial mutants that could resist penicillin began to emerge. At first, penicillin-resistant staph bacteria were confined to hospitalized patients, but they gradually became the dominant organisms in the community as well.

Staph germs are clever, but so are chemists and bacteriologists. In the 1960s, scientists developed methicillin, an antibiotic that was able to kill penicillin-resistant Staph aureus. A large family of similar antibiotics soon followed.

Methicillin and its derivatives soon gained widespread use. And you can guess what happened next: Staph learned how to resist methicillin and similar drugs. Methicillin-resistant Staph aureus, MRSA, was here.

At first, MRSA was found mostly in hospitals. But in the past few years, it has exploded into the community. In both settings, it behaves much like other Staph bacteria: usually existing in the nose or on the skin without causing disease, sometimes producing boils and other mild infections, but occasionally causing life-threatening infections.

Tough as it is, MRSA is vulnerable to special antibiotics, including the one you took. But even after a MRSA infection is cured, the germ can hang out in the nose for prolonged periods, and can be introduced back into the skin or other tissues. In your case, though, it's not clear that your minor foot infection from the splinter was actually MRSA.

You can protect yourself and your family by washing your hands regularly and thoroughly for 20 seconds. For MRSA killing specifically, alcohol-based rubs are best. Don't share personal items like razors or towels. Avoid direct contact with infected patients. And notify your doctor if you develop a new skin infection or another problem that could signal MRSA.