The APIC MRSA prevalence survey: Why?

July 2007

On June 25, 2007, with some media fanfare and in convention assembled, the Association of Professionals in Infection Control released the results of a national prevalence survey of methicillin-resistant Staphylococcus aureus carried out in U.S. health care institutions. I suspect that the detailed results will be published in due course in the Association’s journal, The American Journal of Infection Control. At this writing, I have available only the press release and the executive summary, as posted on the Association’s website.

The stated rationale was as follows: although there has been no dearth of reports from individual institutions or even hospital systems, there have not been coordinated or reliable national estimates of MRSA prevalence since community-associated MRSA began to be recognized as a serious problem. Recognizing this dearth of data, the Association of Professionals in Infection Control (APIC) commissioned and funded this national prevalence survey through its research foundation and retained a highly respected epidemiologist investigator, Bill Jarvis, MD, as the principal investigator. It was probably not a terribly expensive study to do, although investigators like Bill Jarvis probably come dear; several hundred thousand dollars would have done the entire study.

The methodology was quite simple and straight-forward: a survey instrument (nine pages, available on the APIC website) was developed; requests for participation were sent to all APIC members several times between August 2006 and November 2006, and APIC members were asked to recruit non-members to participate. Participants were asked to complete the survey in a single day during the period from Oct. 1 to Nov. 10, 2006. No information was provided about field-testing of the survey instrument or follow-up efforts among non-responders; presumably, this information will be included in the final published report.

Each participating hospital was asked to record a variety of demographic data, including hospital characteristics — whether acute care, rehabilitation, long-term care, pediatric, etc. — number of beds, census, presence of specific high-risk units and the like. Specific MRSA survey data requested included the microbiologic methods used, the site(s) cultured, whether the patient was infected or colonized and whether patients were culture-positive for less than 48 hours or longer 48 hours after admission. Finally, participating hospitals were questioned about their infection control programs, whether active surveillance cultures were done, microbiologic methods used and what isolation procedures were used, if any.

Results available in the executive summary are just that — in summary form only. A total of 1,237 facilities provided data; this represents, according to the APIC summary, 21% of all U.S. health care facilities and 28% of the average daily census. The facilities varied from a low of eight to a high of 1,668 licensed beds and were drawn from every state in the union. No information was provided about the precise characteristics of the participating institutions.

Higher than estimated

MRSA colonization or infection was reported among 8,654 patients, which calculated to a rate of 46.3 per 1,000 inpatients. This rate is quoted as being eight to 11 times higher than previous MRSA estimates. Even if one looks only at patients infected, not just colonized, using clinically indicated cultures, the rate is still 8.6 per 1,000 inpatients. This is still substantially higher than previous estimates.

There was a slight male preponderance; two-thirds of patients were on medical services, 81% were detected by clinically indicated cultures, and 19% by active surveillance cultures. Thirty-seven percent had skin and soft tissue infections only (suggesting CA-MRSA), and 63% had infections at other deeper sites.

Almost all participating facilities used the CDC definitions of hemagglutination inhibition. Twenty-eight percent of participating institutions reported carrying out active surveillance cultures; most used routine or selective media, and only 8% used polymerase chain reaction methodology.

It is important to be aware of what this study did not do, however; it provided no insights into methods of in-hospital spread of MRSA, identified no new interventions, did not assess staff adherence to hand hygiene or other infection control policies, and did not even address the controversial issue of whether active surveillance cultures should be carried out, and on which patients. It was purely descriptive in nature.

Why needed?

Now for the query suggested in the title: why was this survey carried out? So far, I have scratched my head in vain seeking an answer. Did the APIC think that the public, or the funding sources, were largely ignorant of the scope of MRSA problems in hospitals? Were they concerned that MRSA infections had gotten lost, as some believe, in the larger picture of hospital errors and patient safety? Was this a “my issue is more important than your issue” exercise?

Finally, what was the role of industry in this equation? Industry is, after all, a major funding source, and perhaps the major funding source for the APIC Research Foundation. An affordable rapid MRSA diagnostic test, for example, would be a great boon for all hospitals, but especially to those committed to active surveillance cultures; this study is an instant market analysis. Perhaps the passage of time, as well as publication of the final report, will enlighten us further.

One downside of all this, though I am sure it was unintended, is that the data provide more fodder for legislative mills; state legislators, as we know only too well, are always looking for issues about which to legislate to make their constituents happy.

A reprise from last month

King Holmes, MD, PhD, emphatically made the point that HIV/AIDS treatment alone, without preventive efforts, in a setting like Africa is a strategy doomed to fail. On June 20, there appeared an article by Craig Timberg in the Washington Post entitled “Spread of AIDS in Africa is Outpacing Treatment.”

In the article, Francois Venter, MD, of the Johannesburg Hospital AIDS clinic and president of the Southern African HIV Clinicians Society is quoted as follows: “At the moment, I just see a never-ending sea of disaster.”

Venter argues that using antiretroviral drugs to fight AIDS is like using chemotherapy and surgery to fight lung cancer; it would be cheaper and more lifesaving to find some way of reducing smoking. He estimated that it might be possible to reach perhaps half of those who need AIDS treatment, rather than the 20% who receive antiretroviral drugs currently.

“On the public health level, it’s not going to make much of a difference,” Venter said. “I don’t think we’re going to treat ourselves out of this epidemic. No way.”