THE RISING TIDE OF COMMUNITY-ACQUIRED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.

Abstract

Background Since the original community-acquired cases of methicillin-resistant Staphylococcus aureus (MRSA) were first described in the early 1980s, there is an increased awareness of this pathogen throughout the United States. Originally described as outbreaks among those living in close quarters, there appears to be an increase in cases among patients without traditional risk factors. Objectives To determine if the prevalence of CA-MRSA at the University of Mississippi Medical Center (UMMC) is increasing from June 2000-May 2001 to June 2004-May 2005. Secondary objectives are to determine the relationships that health risks, race, gender, and age play in this complex health care issue. Methods All cases of MRSA-positive cultures were identified by the UMMC Microbiology Laboratory from June 2000-May 2001 and June 2004-May 2005. Using previously described inclusion criteria, charts were reviewed and cases were determined to be community acquired. These cases were further characterized by age, sex, ethnicity, and comorbid conditions. Results Of the 453 MRSA cases in 2000-2001, 33 (7%) were determined to be community acquired. Of the 935 cases in 2004-2005, 219 (23%) were determined to be community acquired. This represented a statistically significant increase in the prevalence of outpatient cases from 24 to 129 cases per 100,000 (p Conclusion As has been observed in other parts of the country, CA-MRSA cases have increased in our institution, as have the percentage of MRSA cases that are community acquired. African American ethnicity appears to no longer be associated with a higher prevalence of CA-MRSA in our institution. Although diabetes mellitus and HIV continue to be associated with a higher prevalence of CA-MRSA, the majority of patients with CA-MRSA do not have underlying risk factors.