And finally, the intervention period may not have been long enough to demonstrate an effect. "Previous studies have observed that a reduction in the incidence of MRSA infection may not be evident until a year or more after initiation of an intervention," the investigators said.
They concluded that "merely improving the identification of colonized patients and expanding the use of barrier precautions ... are measures that are not likely to be broadly effective." Additional interventions that "reduce the density of colonization of body sites or contamination of the environment may be necessary."
In the other study, Dr. Rajiv Jain of the Veterans Health Administration and his associates assessed outcomes after implementation of a nationwide initiative to decrease health care–associated MRSA infections in acute care hospitals. The prevalence of MRSA carriage at hospital admission is much higher among VA patients (approximately 14%) than among patients at non-VA hospitals (6.3%) and in the general population (1.5%), they noted.
The intervention called for surveillance of nasal MRSA colonization for all patients who were admitted to the hospital, transferred from one unit to another within the hospital, or discharged from the hospital, followed by contact precautions for all patients who were found to be either colonized or infected with MRSA. As with the intervention in Dr. Huskins’ study, the VA intervention emphasized hand hygiene and "change in the institutional culture" so that all caregivers were held responsible for infection control.
Outcomes were assessed for 1,934,598 admissions, transfers, or discharges at all the medical, coronary care, or surgical ICUs and all the medical, surgical, rehabilitation medicine, and spinal-cord injury units at 150 VA hospitals across the country in 2007-2010.
After the intervention was implemented in 2007, the rate of hospital-associated MRSA infections in ICUs dropped 62% (from 1.64 per 1,000 patient-days to 0.62). The rate of bloodstream MRSA infections not related to a device declined 79% (from 0.14 per 1,000 patient-days to 0.03). The rate of bloodstream MRSA infections related to a device decreased 62% (from 0.16 to 0.06 per 1,000 patient-days), said Dr. Jain, also of the VA Pittsburgh Healthcare System and the University of Pittsburgh, and his colleagues.
In particular, the rate of ventilator-associated MRSA pneumonia in ICUs decreased 72% (from 1.17 to 0.33 per 1,000 device-days), and that of bloodstream MRSA associated with central venous catheters in ICUs dropped 33% (from 0.46 to 0.31 per 1,000 device-days), Dr. Jain and his associates said (N. Engl. J. Med. 2011;364:1419-30).
The rates of other, non-MRSA ICU infections also decreased significantly. The rate of pneumonia not related to a device declined 37% (from 0.35 to 0.22 per 1,000 patient-days), and that of pneumonia related to a device dropped 75% (from 0.32 to 0.08 per 1,000 patient-days). The rate of urinary tract infections also decreased 75% (from 0.16 to 0.04 per 1,000 patient-day), as did that of skin and soft-tissue infections (from 0.16 to 0.04 per 1,000 patient-days).
The results were similar in non-ICU units, where overall hospital-related MRSA infections declined 45%. Bloodstream infection decreased 58%, pneumonia dropped 38%, UTIs declined 44%, and skin and soft-tissue infections dropped 53%.
Contrary to the findings by Dr. Huskins and colleagues, these results "suggest that proactive efforts to prevent the transmission of MRSA are associated with a reduction in [health care–associated] MRSA infections," and that patients in other, non-VA acute care hospitals might benefit from a similar intervention, the investigators said.
Dr. Huskins’ study was supported by the National Institute of Allergy and Infectious Diseases, the National Center for Research Resources, Merck, Elan Pharmaceuticals, Roche Diagnostics, and Kimberly Clark. Dr. Huskins and his associates reported ties to Roche, GlaxoSmithKline, Medegen, and BioNeutral Group. Dr. Jain’s study was supported by the Veterans Health Administration, and no financial conflicts of interest were reported.