The specific aims of this study are to determine the proportion of MRSA among patients presenting from the community with skin and soft tissue infections, and to determine factors associated with MRSA as compared with other etiologies. Eligible patients (18 years of age and over with skin and soft tissue infections and who have material available for culture) presenting to the emergency departments (EDs) were enrolled during the month of August, 2004. Information on demographics, clinical factors, potential risk factors, and treatments received were collected from verbally consenting patients. Purulent material was collected and cultured using standard microbiologic procedures to determine the etiology of the infection. Patients were contacted by telephone two weeks after enrollment to determine the outcome of their infection, subsequent hospital admissions and any additional procedures needed to treat their infection. MRSA and MSSA isolates were sent to CDC laboratories for testing by pulsed field gel electrophoresis to determine relationships between bacterial strains and to determine the presence of certain virulence factors. Finally, patient chart audits were conducted to determine the number of patients we may have missed and whether those we missed were different in terms of age, gender, type of infection, race and disposition, from those who were enrolled. All data were entered onto a web-based data entry module, which was recently created by study investigators (W. Mower and G. Merchant), and analyzed using SAS Version 9.1. Preliminary Results We enrolled 466 patients at all sites. The median age was 40 years (IQR 29-47); 62% were male. Of those with wound cultures done, MRSA was isolated from 59%; the range at different sites was 20%-74%. 97% of the MRSA isolates belonged to the USA300 strain. Other major pathogens included methicillin-susceptible S. aureus 16% and Streptococcus sp. 5.9% (n=25). No clinical or historical features reliably predicted a MRSA etiology. MRSA susceptibilities were: clindamycin 95%, erythromycin 6.1%, levofloxacin 63%, rifampin 100%, tetracycline 92%, trimethoprim/sulfamethoxazole 100%. Of those with MRSA infection (n=251), 73% received antibiotics; and of these (n=182), 57% (n=103) were given an antibiotic to which the pathogen was not susceptible.
Tags:Skin and Soft Tissue Infections