Genitourinary skin and soft tissue infections: A prospective contemporary evaluation of causative pathogens

Purpose: Prior literature identified anaerobes as the predominant causative organisms in genitourinary skin and soft tissue infections. However, the increasing prevalence of community acquired, methicillin resistant Staphylococcus aureus infection has brought about the growing need to reevaluate these infections and their causative organisms. We examined the causative organisms and risk factors in suppurative superficial genitourinary infections, and evaluated the growing role of community acquired, methicillin resistant S. aureus. Materials and Methods: We performed a single institution, prospective assessment of 60 adults who presented between August 2008 and July 2010 with genitourinary skin and soft tissue infections requiring incision and drainage. Patients completed a standardized, nonvalidated questionnaire before undergoing débridement of the site. Results: A total of 60 patient specimens were obtained and 92 bacterial pathogens were isolated. Of these pathogens 55% were aerobes. S. aureus was the most predominant cultured organism, representing 25% of all cultured organisms, and 65% of these isolates were community acquired, methicillin resistant S. aureus. The most commonly associated comorbidities included diabetes mellitus, tobacco smoking and heavy alcohol use. HIV/AIDS showed a statistically significant association with community acquired, methicillin resistant S. aureus infection (OR 11.00, 95% CI 1.05-115.51, p = 0.0456), as did the cumulative number of community acquired, methicillin resistant S. aureus risk factors (OR 2.64, 95% CI 1.31-5.33, p = 0.007). Conclusions: Aerobic organisms now account for most of these infections and community acquired, methicillin resistant S. aureus has emerged as a significant causative organism. Populations that may be at increased risk for these infections include patients with diabetes mellitus, heavy alcohol users and tobacco smokers. In patients with HIV/AIDS or multiple community acquired, methicillin resistant S. aureus risk factors the latter organism is more likely to be the causative organism.