As Many as 1.2M Hospital Patients Infected With MRSA Annually, Study Finds

As many as 1.2 million U.S. hospital patients are infected with methicillin-resistant staphylococcus aureus each year, nearly 10 times as many as previously estimated, according to a study released on Monday at the annual meeting of the Association for Professionals in Infection Control and Epidemiology in San Jose, Calif., the Chicago Tribune reports (Graham, Chicago Tribune, 6/25). For the study, APIC sent surveys to its more than 11,000 member hospitals and nursing homes requesting that members pick one day between Oct. 1, 2006, and Nov. 10, 2006, to record all cases of MRSA infections, both active and colonized. According to APIC officials, 1,237 hospitals and nursing homes responded to the survey, or about 21% of U.S. inpatient health care facilities (Stobbe, AP/Houston Chronicle, 6/25).

The report -- written by William Jarvis, former acting director of the hospital infections program at CDC -- found that 34 of 1,000 patients had active MRSA infections, and 12 of 1,000 patients were colonized with MRSA, which amounts to an MRSA incidence rate of 46 per 1,000 patients. The study suggests that 1.2 million hospital patients are infected with MRSA annually and that 423,000 additional patients are colonized with MRSA, compared with previous CDC estimates that 126,000 were infected annually (Chicago Tribune, 6/25).

According to the survey, the active infection rate is 8.6 times higher than the most recent estimate of the rate of infection by CDC (Russell, San Francisco Chronicle, 6/25). CDC in 2005 estimated that the rate of infection at inpatient hospitals was 3.9 of 1,000 patients, with an estimated mortality rate of 4%. However, some researchers believe that based on the new survey, the mortality rate from MRSA infection could be as high as 10%, according to Lance Peterson, director of infectious disease research at Evanston Northwestern Healthcare. If that mortality rate is accurate, as many as 119,000 patients could die of MRSA annually based on the new data (Chicago Tribune, 6/25).

Additional Findings
The survey found that 67% of infections occurred in nonsurgical medical wards, contrary to previous research that indicated most infections occur in intensive-care units. Seventy-seven percent of patients with MRSA were identified within two days of being admitted to the hospital, "making it likely" that they had the infection prior to admission, according to the Tribune.

Infections often result from an earlier stay at a hospital or nursing home, Jarvis said (Chicago Tribune, 6/25). Earlier studies that have found lower rates of MRSA infections were smaller, focused on specific units of the hospitals and did not count both active and colonized infections, according to Jarvis (Manning, USA Today, 6/25).

Comments
APIC CEO Kathy Warye said, "This study is a real wake-up call to health care workers. It presents a much more comprehensive picture of the burden of MRSA." Lisa McGiffert, manager of the Stop Hospital Infections project of Consumers Union, said MRSA infections are "dangerous" and "there is not enough being done to protect patients from getting them," adding, "Hospitals are going to have to do more. They have to be more aggressive, and it's just not happening" (San Francisco Chronicle, 6/25).

John Jernigan, a medical epidemiologist at CDC and the agency's lead expert on MRSA, said he "applauded the study," although he has not examined its results or methodology. Jernigan added, "Everything we're finding is telling us the same thing: MRSA is an enormous problem in health care facilities, more needs to be done to prevent it and hospitals need to make infection control more of a priority" (Chicago Tribune, 6/25).
The executive summary of the study is available online. Note: You must have Adobe Acrobat Reader to view the executive summary.