Community-acquired MRSA Much More Common in HIV-infected Individuals

Individuals with HIV are at a “markedly increased rate” for contracting a community acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) infection compared with the general population, researchers at Rush University Medical Center in Chicago have found.

Dr. Kyle Popovich, lead author and infectious disease specialist at Rush, and his team of researchers found that the incidence of CA-MRSA skin and soft tissue infections (SSTIs) was 6-fold higher among patients with HIV compared with other patients. The researchers performed the study over seven years, from 2000 to 2007, dividing the years up into two periods: 2000-2003 (period 1) and 2004-2007 (period 2.) Rates of CA-MRSA SSTIs among HIV-infected patients increased from 411 to 1,474 cases per 100,000 HIV-infected patients, during periods 1 and 2, respectively.

“HIV does not cause CA-MRSA, but our study shows an association between HIV and CA-MRSA,” Popovich said.

The study also revealed that rates of CA-MRSA increased within certain areas of Cook County, where Rush’s Medical Center is located. During the first period of the study, 10% of all zip codes within Cook County “had a high rate of MRSA among HIV-infected patients.” By the second period of the study, “that percentage had jumped to 21 percent of zip codes.”

The researchers also looked for the traditional risk factors for CA-MRSA: living in areas of close person-to-person contact, living in zip codes with a high prevalence of former prison inmates, and living in alternative housing, such as a substance abuse treatment facility, shelters, or subsidized housing. In addition to the pattern in rates of CA-MRSA within certain areas of Cook County, these more traditional risk factors for CA-MRSA were also observed.

“We are also now seeing people with community MRSA that aren’t in the traditional high-risk groups,” said Popovich. “We need to bring education to these communities and do more research to determine preventive strategies to address these intersecting epidemics.”