Microbiology and antibiotic management of necrotizing soft tissue infections in Rwanda

Background: Necrotizing soft tissue infections (NSTI) remains a challenging emergency surgical condition with rapid clinical deterioration, microbiological variability and increased morbidity and mortality. Methods: This prospective cohort study includes all adult patients with NSTI managed at University Teaching Hospital of Kigali Department of Surgery from April 2016 to January 2017. The objective was to describe bacterial pathogens involved, antimicrobial sensitivity patterns and antibiotic costs. NSTI were classified based on type and comparisons were made between NSTI type and patient characteristics. Analyses were conducted using Kruskal-Wallis test for continuous variables and Pearson chi-square test for categorical variables. P-value u003c 0.05 was considered significant. Results: We enrolled 175 NSTI patients during the study period. 103 (59%) patients had type I NSTI and 21 (12%) patients had type II NSTI. Fifty-one (29%) patients were of undetermined type. Most organisms were gram-negative pathogens (n=121, 81%) with Klebsiella spp (n=38, 25%) being the most commonly isolated gram-negative pathogen. Monomicrobial organisms identified included Klebsiella spp (n=28, 16%), Escherichia coli (n=22, 13%), Proteus spp (n=20, 11%), and Staphylococcus aureus (n= 19, 11%). Third generation cephalosporins were prescribed in 136 (78%) patients. 65% of Klebsiella spp isolates and 40% of Escherichia coli were resistant to third generation cephalosporins. Antibiotic costs for pathogens with third generation cephalosporin resistance were ten-fold greater than commonly used antibiotics. Conclusions: NSTIs are found to be predominantly mono-microbial with high resistance to third generation cephalosporins. A large-scale antibiogram study is needed to guide clinician decision-making for empiric antibiotic coverage in NSTI to improve patient outcomes.