Confusion about MRSA reaching epidemic proportions

MRSA outbreaks are nothing compared to the outbreak of media distortion about MRSA. The latest barrage was sparked by the report of the MRSA related death of a Virginia high school student as well as this paper in JAMA which updates the epidemiology of MRSA.

In an attempt to parse what’s going on let’s start with the story of the Virginia high school student. The Associated Press report reads:

BEDFORD, Va. (AP) — A high school student who was hospitalized for more than a week with an antibiotic-resistant staph infection has died. After a student protest, officials shut down 21 schools for cleaning to keep the illness from spreading.

Ashton Bonds, 17, a senior at Staunton River High School, died Monday after being diagnosed with Methicillin-resistant Staphylococcus aureus, or MRSA, his mother said.

Although we have no information about the infecting strain, be it the “old MRSA” typified by the USA100 strain or the “new MRSA” typified by USA300 (although pulsed-field typing was probably not done in this case the strain could easily have been inferred from the sensitivity pattern for antibiotics other than methicillin as I explained here) it was most likely the former.

The significance of the JAMA article is that it is the most systematic analysis of the epidemiology of invasive MRSA in the U.S. to date and despite its limitations suggests that the infection is more widespread than had been appreciated. The paper is “busy” with data and somewhat confusing categorizations. (An editorial in the same issue provides clarity). Infections were classified on the basis of site of onset (health care or community) and on the basis of risk factor associations (health care or community). Pulsed field typing was available for a minority of isolates. Considerable overlap among all 3 methods of categorization suggests limitations on the popular designations “community associated” and “health care associated”. Nevertheless MRSA comprises at least two different beasts with important clinical associations, best typified by pulsed field types USA100 and USA300 and usually distinguishable to clinicians by characteristic antimicrobial sensitivity patterns. While I decry the media’s “killer superbug” hype I did point out, almost 2 years ago, that the “new” MRSA had unique potential for increased transmissibility and severe necrotizing infections.

Now let’s examine some of the media distortion. I did a Google News search for MRSA and had difficulty finding articles that provided appropriate perspective. This Q and A piece defines MRSA as “a type of staph bacterium that is resistant to common antibiotics such as penicillin.” Not quite. Penicillin sensitivity is rare even among non-MRSA isolates.

Many articles talked about schools closing for a good scrubbing down following the reports of MRSA infections in Aston Bonds and other students. However, given the importance of person to person spread of MRSA it’s unlikely that environmental sanitation measures would have much impact. This article implies that poor hospital cleaning was responsible for MRSA sepsis and death in a newborn. But almost a year ago I cited a lack of evidence of correlation between hospital cleanliness and MRSA bacteremia. In hospitals hand washing and proper use of isolation procedures, rather than environmental cleanliness, will make the most impact. Equally important are sanitation measures for infected patients to follow after hospital discharge, which I provided here.

This superbug article declares:

All schools should be disinfected. Regularly. And we need to educate ourselves about this increasingly aggressive disease that few drugs can defeat.

There may be good reasons for environmental disinfection, but such measures won’t contain MRSA. Kids bring these bugs form home and pass them to others via direct contact or sharing of items of personal hygiene, also brought from home in many cases. Utensils and items of athletic equipment are reasonable areas of focus for schools.

It’s simplistic to characterize the “new” MRSA, the one that’s getting all the attention in schools, as a problem of increasing antimicrobial resistance. For milder cases several antibiotics are effective, including a few old ones (Bactrim, tetracyclines). The problem is these are not the same old antibiotics (cephalexin, diclox) we’ve been used to using to treat community acquired skin infections. To make it a bit more challenging, the ones that work for the new MRSA aren’t effective against group A strep which is still a common cause of skin infections. The new MRSA happens to be susceptible to more antibiotics than the old MRSA that’s been quietly making the rounds in hospitals for years.

There’s plenty more hype, but I’ll stop there. I can imagine how the reporter felt as she researched her daughter’s ordeal with MRSA: “I became a mouse-click medical expert. The more I read, the more I feared”.