Fuel for the fire: MRSA prevalence study may spark state infection control laws
APIC: Findings are a call to action for hospitals
An unprecedented prevalence study that revealed an epidemic of methicillin-resistant Staphylococcus aureus (MRSA) in the nation's hospitals will likely accelerate fires that already were smoldering in many state legislatures. Expect the shocking findings that MRSA prevalence is eight to 11 times higher than previous estimates to be presented as "Exhibit A" in consumer and patient safety demands for state laws specifically targeting MRSA detection and prevention in hospitals.
Commissioned by the research branch of the Association for Professionals in Infection Control and Epidemiology (APIC), the MRSA study was unveiled recently in San Jose at the annual APIC conference. Even those who expected the worst may have underestimated these findings, as a one-day "snapshot" study conducted last year found that 46 out of every 1,000 patients in participating facilities of all stripes and sizes were colonized or infected with MRSA.
The findings drew plenty reaction from the press, patient safety advocates, consumer groups and even some ICPs who openly questioned whether such troubling data may spur state laws mandating infection control measures against MRSA. Many state legislatures are currently mulling MRSA legislation, much of it tied to recommendations by the Society for Healthcare Epidemiology of America to implement active surveillance cultures (ASC) to detect the patients with MRSA and place them in contact isolation to prevent transmission to others.1 However, there is considerable controversy about the practice within epidemiological circles, and even proponents of ASC have come out against mandating clinical practice through state laws.
'Why did we go into infection control?'
Still, the suggestion that a line of scientific inquiry should not be pursued out of fear of unintended consequences was troubling to the veteran epidemiologist who designed and administered the MRSA prevalence survey for APIC. Now a private consultant, William Jarvis, MD, formerly was a leading investigator of hospital outbreaks for the Centers for Disease Control and Prevention. "I must admit I was somewhat dumbfounded with that reaction," he tells Hospital Infection Control. "Why did we go into infection control? I don't know about anybody else but I went into it to prevent these infections from occurring, not to count them and see them keep going up. [But] one of the disturbing things with the mandatory reporting legislation and virtually all other infection-associated legislation is that none of them demand or require any increase in infection control personnel. They are unfunded mandates and if you do that nothing is going to change."
But change could still come in the form of the many positive signs afoot for MRSA prevention, including the massive reduction and eradication effort that has been undertaken by the Veterans Affairs hospitals and other hospital chains. "I am hopeful that this [study] will lead to administrators recognizing that this is a problem they really need to address and they need to provide the resources to do it," Jarvis says. For their part, ICPs and health care epidemiologists must be passionate in insisting endemic levels of MRSA are no longer acceptable, he argues. "We should all be furious unless we see those rates going down," Jarvis says. "If the rates are not going down, you need to do more. I don't care where you are or what kind of facility you are in, we are in infection prevention."
'MRSA not only bug in town'
Other speakers at APIC defended the study while emphasizing that it should not be used to pass legislation aimed at a single bug. "As scientists we should never be opposed to advancing scientific knowledge," Tammy Lundstrom, MD, JD, medical director for epidemiology at the Detroit Medical Center, told APIC attendees. "This is a first, one-of-a-kind study. I feel very strongly that there is so much that is yet unknown about MRSA that we need a lot of research. I don't think we should ever be opposed to increasing knowledge, but certainly we are opposed to legislating in one approach that is a portion of a bigger program."
Indeed, the educational challenge ICPs must face after the highly publicized release of the findings is to address heightened concerns about MRSA among the public, patients, press, and staff without letting a host of other infection control concerns get swept aside in process. "MRSA isn't the only bug in town for a lot of our facilities," Lundstrom said. "If you look at the cost of these multidrug-resistant organisms [MDROs] — whether you are talking about MRSA, VRE, or extended-spectrum beta-lactamase gram-negative organisms — there is a higher cost for caring for patients, a longer length of stay and, in many cases, higher attributable mortality than with sensitive organisms. But we also have to be concerned about sensitive organisms, because if a patient dies from [drug-susceptible S. aureus], it is no less tragic than if a patient dies from MRSA."
Echoing Jarvis sentiments, Denise Graham, vice president of public policy at APIC, told conference attendees to use the prevalence findings as "a call to action for health care administrators. We want very much for them to put the necessary resources in place to help you — not just with MRSA but with other [infections]. . . . This has been a bit emotional in the newspapers, but the study has been done. Do we want newspapers to pick up and interpret the wrong message or do we want to help shape that message? You're the professionals and we should be helping you shape that message."
The bug in the smoke-filled room
The message will be critical as an increasing number of state legislatures put some form of MRSA law on their agenda for discussion. Illinois appears to be close to passing such a law, which was "on the governor's desk" as this issue went to press, she noted. Several other states are at looking at MRSA legislation, which is a hot topic at national legislative meetings where state lawmakers rub shoulders and share ideas that may endear them to constituents back home. "If you are wondering why this is taking off, it is kind of like the public reporting [of hospital infection rates] initiative," Graham said. "Consumers get on it, the emotional stories are out there and it quickly moves across the country."
Indeed, there was already so much interest among state legislatures regarding MRSA laws that an increase in bill proposals was anticipated by trend trackers even before the prevalence study was completed. "We have heard from a lot of states that did not introduce legislation officially [this year]," she said. "So, next year you are going to see an awful lot more. Whether we provided our study or not wasn't really going to matter. States are looking at it because they are hearing from their constituencies."
They will hear from them a lot more if the Consumers Union — publishers of Consumer Reports — has anything to do it. The group has launched a letter writing campaign to state governors urging them to implement ASC and other measures against MRSA in their state hospitals. As soon as the APIC MRSA prevalence study was released, Consumers Union issued a release calling for "hospitals to take more aggressive steps to protect patients from MRSA infections in light of a new study showing that the superbug is much more common in hospitals than previous estimates had indicated. The Committee to Reduce Infection Deaths (www.hospitalinfection.org) used the findings to criticize the Centers for Disease Control and Prevention, charging in a press release that the findings "confirm [a] CDC cover-up and the urgent need for cleanliness standards and MRSA screening in U.S. hospitals."
While praising the findings of the APIC study, a leading CDC epidemiologist on MRSA defends the agency's infection prevention approach to MRSA and other MDROs and says one study will not change them.
"I don't think it changes anything in the way we are looking at [the problem of MRSA]," says John Jernigan, MD, a medical epidemiologist in the CDC division of healthcare quality promotion. "It is consistent with many previous estimates that suggest that there is way too much MRSA in U.S. hospitals. We have been working very actively in putting prevention programs that are effective in reducing MRSA rates. We actually applaud the study. It is another piece of evidence that suggests that MRSA continues to be an enormous problem in health care facilities."
Jernigan defended the approach outlined in the 2006 MDRO guidelines. Those CDC guidelines use two-tier approach, with hospitals going to more aggressive measures such as ASC if rates are not going down.2 "I don't think there are any plans to change the MDRO guidelines based on this study," he tells HIC. "If hospitals are able to reduce or even eliminate MRSA with recommendations that are contained in Tier 1, then I'm not sure what the point would be in asking them to do more. On the other hand, if they are not [reducing rates], then the guideline says you need to do more. And in fact, active surveillance is part of those [additional] recommendations."
An under- or over-estimate?
Concerning the striking increase in MRSA prevalence from prior estimates, Jernigan noted that the survey approach used a very different methodology than approaches used in other studies. "A lot of the differences in numbers has to with the methodology," he says. "For example, they looked for evidence of infection and colonization. It was a voluntary study so it may be that hospitals that had particularly bad problems were more likely to want to participate."
However, even if the survey findings are winnowed down to only the MRSA-infected, the resulting rate of 34 per 1,000 inpatients still is 8.6-fold higher than the most recent estimate by CDC researchers.3 The primary sources for previous estimates have been discharge data or surveillance data from CDC sentinel hospitals in the National Nosocomial Infection Surveillance (NSIS) system, both of which likely underrepresent the burden of MRSA nationally, Jarvis contends. "You look at the landscape of all the data that are out there and realize we really didn't have a good estimate, and we knew that when I was at CDC," he says. "We are looking at point prevalence [in this study], so it is kind of a snap shot of single day vs. the previous studies that have been estimates made on incidence data. The results of the survey show the extent and depth of the problem. We really had widespread distribution geographically and of various hospital types — not just 210 NNIS ICUs at large teaching hospitals. A large proportion of the respondents were people that don't get tapped in the NNIS database."
A minimum estimate?
While conceding the survey methodology is different than other studies, Jarvis cited other factors to support his contention the data gleaned from the study likely represent an underestimate. "I think the results are a minimum estimate," he says. "If everybody at every facility was doing very aggressive clinical cultures, then secondly they were doing active surveillance cultures — and using for both of those the most sensitive [laboratory] methods they could use — the numbers are only going to go up."
Indeed, only 28% of 1,237 responding facilities said they were using ASC methods to detect patients colonized with MRSA. Moreover, many of those using ASC reported doing so with rudimentary laboratory methods — meaning cases were likely going undetected even in hospitals looking for them. Of those performing active surveillance testing for MRSA, 54% used routine media and 38% used selective media. Only 8% used the gold standard of polymerase chain reaction (PCR) to detect MRSA colonization.
"It looked like that many of the facilities that were doing ASC had done some kind of risk assessment beforehand and were targeting high-risk populations," Jarvis says. "What was kind of surprising to me was that — number one, only 28% of them were doing ASC on anybody — and secondly, the majority was still using a nonselective media. That is the least sensitive of the [laboratory] methods that we have out there."
'We found it everywhere'
Despite such limitations, that survey netted widespread reports of infected and colonized MRSA patients from all types of facilities, exploding the myth that the bug is primarily a problem for large hospitals. "We found it everywhere," Jarvis says. "It didn't matter what the size of the facility was or geographically where you were. The rate was very high and the majority was health care-associated."
CA-MRSA not driving results
Though it was not possible to truly delineate hospital strains of MRSA from emerging community-associated MRSA, the findings primarily reflect traditional hospital infections, Jarvis says. Despite the fact that many infections were diagnosed before the 48-hour cut point — a traditional measure used to differentiate infections acquired in the community vs. the hospital — previous studies have shown that most patients coming in with MRSA will have a history of health care exposure rather than true community-acquired infection, he notes.
"It is clear that using that 48-hour cutoff is not a very precise measurement of community vs. health care-associated, but I wanted to collect that data because I think a lot of people do use it," he says. "My guess is that we are actually even overcalling CA-MRSA vs. health care-associated in this survey because we are using artificial cut points."
Still, in survey data broken down on 7,944 patients with MRSA, 37% had skin and soft-tissue infections, which often are seen with CA-MRSA. There has been speculation that the rapid emergence of the USA300 strain of CA-MRSA could fuel a national increase in prevalence, and indeed some reports indicated the strain has simply displaced traditional strains in some hospitals. For the most part, however, CA-MRSA infections are occurring beyond the hospital and thus would not be reflected in the survey, Jarvis contends. "The majority of those patients end up in a [physician] office, emergency department, or outpatient clinics," he says. "They get seen, lanced, get an antibiotic, and go home. So under any circumstances only a minority of patients with CA-MRSA get admitted to the hospital in the first place. Certainly in our data, looking at the magnitude and prevalence of MRSA, the large proportion of it is health care-associated and not community-acquired."
Jarvis contrasted the study findings with the prevalence estimates in the late 1970s and early '80s when epidemiologists were just beginning to get a clear picture of emerging MRSA. "It's rather amazing when you look at that and see where we were sitting at that time," he says. "Many hospitals had virtually no MRSA, and even some large hospitals were only seeing like five cases in five years. Look at what it is now. I think that virtually every hospital in the country has MRSA and many of them have endemic MRSA."
Though preferring to be characterized as a proponent of prevention rather than simply an advocate of ASC, Jarvis has lobbied for the practice on many an occasion and clearly sees it as part of the solution. "For MRSA, it is quite clear from the huge body of literature now — there are almost 200 studies, either published papers or abstracts — showing that if you do a risk assessment, target active surveillance cultures for high-risk patients, put them in contact isolation, and reinforce hand hygiene and environmental cleaning that you can have a dramatic impact on reducing MRSA," he says. "I don't know of anyone who has done that — and who has got compliance — and has not seen a reduction in MRSA."
Jarvis also rejects the argument that a focus on MRSA will lead to a rise in other infections. "I am not aware of [any studies] where MRSA has been controlled or at least moved in the direction of controls and other organisms have gone bananas," he says. "Our infection control personnel are smarter than that."
References
- Muto CA, Jernigan JA, Ostrowsky BE, et al. Special Report: SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and Enterococcus. Infect Control Hosp Epidemiol 2003; 24:362-386.
- Centers for Disease Control and Prevention. Siegal JD, Rhinehart E, Jackson L, et al. The Healthcare Infection Control Practices Advisory Committee Management of Multidrug-Resistant Organisms in Healthcare Settings, 2006. On the web at: www.cdc.gov.
- Kuehnert MJ, Hill HA, Kupronis BA, et al. Methicillin-resistant-Staphylococcus aureus Hospitalizations, United States. Emerg Infect Dis [serial on the Internet]. 2005 Jun. Available from www.cdc.gov.
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