Methicillin-resistant staphylococcus aureus or MRSA infections are usually mild. But they can cause serious health issues for some patients. A talk Wednesday, March 6, in Springfield will focus on the prevalence of and virulence factors associated with MRSA.
Dr. Jean Escudero is an assistant professor of microbiology at St. Louis College of Pharmacy, and she'll be in Springfield as part of “STLCOP Talks.”
She said, if a person's immune system is already weak or their defenses are down, a MRSA infection can be very serious. According to Escudero, MRSA can create toxins or enzymes called exoenzymes "that actually help it invade our body and destroy parts of our body."
How serious an infection is, she said, depends on the strain one gets, their health and how they're exposed to it. Infections can range from a spot the size of a pimple to an abcess that needs to be drained. In some cases MRSA infections can cause a life threatening illness such as pneumonia or endocarditis--a biofilm on the heart valve that prevents the heart from functioning as it should, according to Escudero.
MRSA is different from other staphylococcus aureus in that it is resistent to beta lactams--antibiotics commonly used to treat infections such as Penicillin or Oxacillin. Escudero said, when Penicillin was introduced in the 1940s, resistent strains of staph aureus were immediately detected. They produced an enzyme called beta lactamase "that would sort of chew up the antibiotic so it wouldn't be functional," she said. MRSA is different. It will pick up a piece of DNA--mecA--a gene that Escudero said "encodes for an extra protein."
Beta lactams, such as Penicillin, block the enzymes that help build a strong cell wall in an organism. The drugs bind onto those enzymes, according to Escudero, and don't let them build the wall, so the cell is weakened.
"But with MRSA, they have an extra enzyme, and that extra enzyme is called PBP2a, doesn't even acknowledge that the beta lactam is present, and it keeps building a strong cell wall, " she said, "so even though the other enzymes could be shut down, this one enzyme builds a cell wall, and the bacterium is not affected by the antibiotic."
People most commonly get MRSA through direct contact with other people or from touching inantimate objects such as door knobs or desks. It can survive on surfaces for up to 90 days. Escudero said many of us carry staph aureus on our skin, and some also carry MRSA.
"As long as it's just on your skin, it's not doing anything to you, but you can pass it to other people and then if you have some sort of cut or something, it can get into your body," she said, "and that's where it causes the problems."
Some pharmacists and physicians believe that prescribing a combination of drugs--a beta lactam and something that inhibits the protein synthesis--is a good way to treat skin infections that could be MRSA, according to Escudero. If someone is given a beta lactam, and their infection turns out to be MRSA, the drug won't be effective, she said, "and it might take a little while before it's obvious it's not helping, and, in the meanwhile, this organism is replicating and possibly damaging the body."
There are steps a person can take to try to prevent a MRSA infection such as cleaning and covering wounds.
"And you don't need anything fancy," said Escudero. "Soap and water is usually fine. If you have a cut, keep it covered so it's not exposed to the elements because the skin is your first line of defense, and if it's cut open you're kind of saying, 'come on in if you want.'"
During STLCOP Talks in Springfield, Escudero will discuss a study she had her students participate in that looked at where MRSA is found in pharmacies.
"I thought, if they could look at the pharmacies in which they work and look to see the presence of staph aureus and MRSA, maybe they could help shed some light on the potential role they may be playing inthe transmittance of this organism," she said.
The students took swabs at two hospital pharmacies and two retail pharmacies on things like counters, various machines and badges technicians use to swipe in and out of rooms.
"And what we found is, there was quite a bit of staph aureus present, and some of it was MRSA," said Escudero.
Out of 66 samples, taken in the hospital pharmacies, 30 were positive for staph aureus, and, of those, 16 were MRSA. And there might have been other organisms present, like eColi, that the study didn’t look for.
But Escudero said if a facility steps up its cleaning process just a little bit, even with just soap and water, the risk for transmitting staph aureus is greatly reduced.
Her talk is Wednesday night, March 6, at 6:30 at Metropolitan Grill, 2931 E. Battlefield. Other topics will include treatment approaches for opioid addiction during pregnancy and the college's efforts to improve over-the-counter medicaiton knowledge among pharmacists in India. The talks are designed for STLCOP alumni, but the public is invited. RSVPs are requested at stlcop.edu/alumni/events or (314) 446-8419.
