Study identifies high-risk patient populations for MRSA carriage

A Rhode Island Hospital study presented at the Society for Healthcare Epidemiology of America (SHEA) annual meeting found that patients in long-term elder care and HIV-infected outpatients appear to be high-risk groups for carriage of methicillin-resistant Staphylococcus aureus (MRSA), a common cause for health care associated infections.

"MRSA can be spread in the healthcare environment and community and can cause serious infections," said lead investigator Leonard Mermel, MD, medical director, department of epidemiology & infection control, Rhode Island Hospital. "Identifying patient populations that have a high risk of MRSA carriage is important in our efforts to control the spread of this microbe among patients."

In the prospective, multi-center trial, which was funded by 3M Health Care, clinical nasal swabs were collected from various patient groups at 11 sites in the country, including inpatients screened for MRSA through active surveillance, inpatients and outpatients requiring hemodialysis, inpatients and outpatients with HIV-infection, pre-op cardiac surgery patients and patients admitted from long-term elder care.

Among patients at facilities that did not regularly screen for MRSA, prevalence of MRSA was highest in patients admitted from long-term care (18 percent) and HIV-infected outpatients (17 percent), suggesting these patient populations are at especially high risk of MRSA carriage. In addition, this trial is the first to look at the quantity of MRSA in the nares (openings of the nasal cavities) of different patient populations.

Currently, the standard method to detect carriage of MRSA is by routine culture whereby results can take several days. Delayed results can lead to MRSA transmission since potential MRSA carriers are often not isolated from patients without MRSA until these results are available.