CDC Warns Community-acquired MRSA Threat is Growing

Hospital outpatient settings are grappling with a rate of methicillin-resistant Staphylococcus aureus that has doubled between 1999 and 2006, an increase caused almost entirely by community-acquired bacteria strains, according to a new CDC report.

The rapid rate of infection spread threatens inpatient settings as well, according to the December issue of the Centers for Disease Control and Prevention's Emerging Infectious Diseases, which summarizes findings from 300 microbiology labs serving U.S. hospitals.

"The frequency of community-acquired (CA) MRSA among inpatients increased nearly in conjunction with outpatient rates, overall and at each infection site," according to the report.

"Despite increases in the proportion of CA-MRSA strains among inpatients, the continuing high level of (hospital-acquired) HA-MRSA suggests that in contrast to reports from local institutions, CA-MRSA strains are adding to the problem of MRSA rather than replacing HA-MRSA strains."

The report added that some "crowding out of HA-MRSA strains within the hospital may be occurring." However, hospital-acquired strains may be "more fit, and thus CA-MRSA strains are unable to replace them fully. The result is a coexistence of both strains in the hospital and maintenance of CA-MRSA because of the large influx of colonized and infected patients."