Causative pathogens, antibiotic sensitivity, resistance patterns, and severity in a contemporary series of Fournier's gangrene

Abstract

Objective: To identify the causative pathogens and evaluate the antibiotic sensitivity, resistance patterns, and virulence in a contemporary series of patients with Fournier's gangrene.

Materials and methods: The medical records of 41 consecutive cases of Fournier's gangrene were evaluated. The patient demographics, causative pathogens, antibiotic sensitivity, and resistance patterns were assessed. The Fournier's gangrene severity index and length of stay were analyzed statistically to determine any differences by causative pathogen.

Results: A total of 122 pathogens were cultured. The wound cultures were polymicrobial for 34 patients (83%). Most common pathogens cultured were Bacteroides sp (43.9%), Escherichia coli (36.6%), and Prevotella sp (34.1%). E coli was resistant to fluoroquinolones and trimethoprim/sulfamethoxazole in 13.3%, and 40% of isolates respectively. The wound cultures were monomicrobial for 7 patients (17.0%). A monomicrobial isolate of methicillin-resistant Staphylococcus aureus was cultured that was susceptible to clindamycin and trimethoprim/sulfamethoxazole. Resistance to ampicillin-sulbactam was seen in Providencia sp, Klebsiella sp, E coli, and methicillin-resistant S aureus. Resistance to ceftriaxone and gentamicin was seen in methicillin-resistant S aureus and E coli, respectively. No resistance to clindamycin was demonstrated. No statistically significant difference was detected between the Fournier's gangrene severity index or length of stay and the causative pathogens.

Conclusion: Fournier's gangrene remains a community-acquired polymicrobial infection, with anaerobic bacteria as the most common causative pathogens. Candida and methicillin-resistant S aureus are emerging causative pathogens, but methicillin-resistant S aureus remains sensitive to clindamycin and trimethoprim/sulfamethoxazole. Although resistance was demonstrated by some causative pathogens, together, the currently recommended broad-spectrum antibiotics adequately covered all pathogens. Coverage with agents such as fluconazole, vancomycin, or piperacillin-tazobactam is indicated in patients at risk of fungal or hospital-acquired organisms.