Pressure continues to build for healthcare facilities to act to decrease hospital-acquired infections, particularly those associated with MRSA. This is partly data-driven, with one study reporting that 25% of patients acquiring MRSA colonization during a hospitalization subsequently become infected . The call to act is also partly a political response to concerns in the lay press about “superbugs” wreaking havoc both in hospitals and in the community. Seven states have either passed legislation or are considering bills to mandate admission screening cultures (ASC) for MRSA. Some restrict the mandate to ICUs; others do not.
The evidence basis for decisions as to how best to address MRSA in hospitals is growing, although no response is accepted by all. One of the more contentious issues is the value of admission screening cultures to identify colonized patients who may then be isolated and perhaps decolonized. The debate continues as many trials, some with conflicting results, are reported from different settings, utilizing various combinations of interventions (e.g., rapid PCR-based vs. agar culture-based screening, decolonization vs. no decolonization), with non-uniform endpoints (e.g., transmission rates vs. infection rates). Thus a consensus has not developed. Last month a systematic review of 20 relevant papers published through September 2007 was reported in Clinical Infectious Diseases . The authors conclude that “the overall quality of the evidence is poor; thus, definitive, evidence-based clinical recommendations cannot be made.”
Two studies have since been reported and are widely cited. In March, JAMA published the results of a Swiss study examining 21754 surgical patients assigned either to ASC and contact isolation, with decolonization and adjustment of perioperative antibiotics, or to standard infection control, in a crossover design . Rates of MRSA surgical site infection and nosocomial MRSA acquisition did not change significantly in the intervention group, although a low baseline infection rate was noted.
Also in March, the Northwestern University School of Medicine’s 850-bed hospital system reported on its experience, comparing infection rates following the institution of universal screening to historical rates . A 50% reduction in hospital-associated MRSA infections was noted over the 21 months when universal surveillance and isolation was in place. Although decolonization was included as part of the control strategy, adherence to that part of the program was not monitored. Although the reduction in infection rate is impressive, the contribution of the ASC component of the protocol per se needs to be defined. Would screening and decolonization of targeted populations have achieved similar results, at lower costs? Was adherence to standard infection control procedures so substantially improved as to account for a significant reduction in infection rates? Many believe more study is required and that the “one-size-fits-all” approach in different healthcare settings is not appropriate.
While each of the three major NYU teaching hospitals are committed to reducing healthcare-associated infections, their approach to ASC for MRSA differs. While at Tisch Hospital, active surveillance is performed in the 15East ICU, and time-limited surveillance is performed in the Bellevue ICU, the VA performs active surveillance cultures on all admissions to the facility, and on all transfers between wards, as part of a national VA-wide initiative. Whereas both Tisch and the VA place all patients either infected or colonized with MRSA on contact precautions, at Bellevue colonized patients are placed on contact precautions only if a portal of exit is identified. Does this lack of uniformity within the NYU community represent differing views amongst its Infection Control staff? No. Again, these are facilities with different populations, infection rates, and resources. Although favorable cost analyses for ASC have been published , hospital-specific factors may tilt the outcomes of such analyses significantly. There are many unanswered questions, and more research needs to be done. As of this writing, the CDC’s Healthcare Infection Control Practices Advisory Committee (HICPAC) 2006 recommendations remain in place, with ASC suggested only when “baseline measures fail” to reduce high MRSA infection rates.
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Image courtesy of Wikimedia commons, scanning electron micrograph of MRSA