SAN FRANCISCO — Methicillin resistance was noted in 69% of community-acquired soft tissue infections due to Staphylococcus aureus in a single-center study of hospitalized adults in Detroit.
Additionally, more than half of the community-acquired methicillin-resistant Staphylococcus aureus [MRSA] infections were associated with abscesses, Dr. Houssein Jahamy reported in a poster presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
MRSA was the etiologic agent in 136 (69%) of the 198 patients hospitalized with a soft tissue infection caused by S. aureus between Nov. 1, 2005 and June 1, 2006 at St. John Hospital and Medical Center in Detroit, reported Dr. Jahamy, a second-year infectious diseases fellow at the hospital. Abscesses were noted in 57% in the MRSA group and in 28% of those with methicillin-sensitive S. aureus infections.
“Right now we are seeing plenty of patients with community-acquired MRSA,” Dr. Jahamy said in an interview. “Some show up at the hospital or clinic complaining of a spider bite.” In most cases, the “spider bite” is a furuncle. “That's a big tip-off that they probably have community-acquired MRSA.”
He and his associates reviewed the microbiology findings for all patients hospitalized with community-acquired soft tissue infections. They also collected information on demographics, comorbid conditions, type and location of initial lesion, and evidence of bloodstream invasion or other complications.
Compared with methicillin-susceptible S. aureus infections, those caused by MRSA were more likely to occur in women (77%) than in men (62%), in patients who did not have diabetes (73%) than in those with diabetes (60%), and in those who did not have a comorbidity (75%) than in those with comorbidities (65%). In line with findings that MRSA infections are more likely to be seen in patients with few comorbidities, MRSA-infected patients had shorter average hospital stays—6 days, compared with 8 days in those with methicillin-susceptible infections.
Dr. Jahamy and his coinvestigators observed no significant differences between the MRSA and methicillin-susceptible S. aureus groups in terms of history of spider bite (7% vs. 4%, respectively), infections that started as a furuncle (23% vs. 18%, respectively), or incidence of bloodstream invasion (6 vs. 9%, respectively).
Dr. Jahamy reported that he had no financial disclosures associated with the study.