As many as 1.2 million hospital patients are infected with dangerous, drug-resistant staph infections each year, almost 10 times more than previous estimates, based on findings from a major new study by the Association for Professionals in Infection Control & Epidemiology (APIC), which is released the report on Monday. The author is Dr. William Jarvis, former acting director of the hospital infections program at the Centers for Disease Control and Prevention.
And 48,000 to 119,000 hospital patients a year may be dying from methicillin-resistant staphylococcus aureus (MRSA) infections, far more than previously thought, the study concludes.
The study is the largest, most comprehensive survey of MRSA in health-care facilities to date. It’s based on surveys sent last year to 10,000 infection-control practitioners, including doctors and nurses in hospitals, nursing homes and rehabilitation facilities. The findings come amid mounting public concern about the spread of antibiotic-resistant bacteria in health-care facilities and community settings. Medical experts consider the rise of so-called superbugs such as MRSA, a leading cause of deadly blood infections and pneumonias, one of the most alarming public health threats in the nation.
Health-care professionals were asked to select one day between Oct. 1 and Nov. 10, 2005, and report all known MRSA cases in their institutions. More than 1,200 hospitals and 100 nursing homes and rehabilitation facilities responded, supplying data about patients with MRSA infections and patients colonized with the bacteria.
The new survey confirms what’s been observed anecdotally for years — MRSA is rampant in health-care facilities. People colonized with MRSA typically carry it in their nose without being symptomatic. They’re at risk of passing the superbug to others unknowingly. MRSA can live on surfaces for days or even weeks.
The results found that 34 of 1,000 patients in the survey had active MRSA infections and that 12 were colonized with the superbug, for a total MRSA prevalence rate of 46 per 1,000 patients. The most widely cited previous study, published by CDC researchers in June 2005, had estimated that the MRSA infection rate at in-patient hospitals was 3.9 per 1,000 patients. Based on that rate, it estimated that 126,000 patients were infected with the superbug each year.
To determine the overall rate of infection based on the new findings, the calculation involves 35.2 million people hospitalized in the U.S. in 2005, the latest year for which information is available. Applying the prevalence rates in the new study, the data suggest that 1.2 million hospital patients are afflicted with MRSA each year and that an additional 423,000 patients are colonized with the superbug.
The CDC has said at least 5,000 patients die after being infected by MRSA at surgical sites, in their blood or in their lungs. That’s a mortality rate of 4 percent, assuming a base of 126,000 patients. Using new prevalence estimates of 1.2 million MRSA patients a year, it suggests 48,000 patients a year may die of MRSA.
The study shows that 77 percent of patients with MRSA were identified within two days of entering a hospital, making it likely they were colonized or infected before being admitted. The vast majority of these patients picked up MRSA during an earlier stay at a hospital or nursing home, according to Dr. Jarvis.