Prevalence of multi-drug resistant bacteria causing surgical site infection at tertiary hospitals in Dar es Salaam, Tanzania: a call for strengthening infection prevention and preoperative prophylaxis

Background Surgical site infections (SSI) are common healthcare-associated infections, yet data on causative bacteria and antimicrobial susceptibility patterns are limited. The study aimed to determine the bacterial pathogens and antimicrobial resistance patterns among post-operative patients at tertiary hospitals in Dar es Salaam, Tanzania.Methods We conducted a cross-sectional study between September 2022 and February 2023 to investigate SSI through an aerobic culture of pus aspirates or wound swabs. Isolates were identified using conventional methods and an analytical profile index 20E test for Enterobacterales. Antimicrobial susceptibility testing was performed using Kirby Bauer disc diffusion methods. Continuous variables were summarized as mean and standard deviation, while categorical variables were summarized as proportions.Results A hundred-fifty-eight patients were enrolled, with a mean age of 42.20 ± 12.13 years. Of 158,140(88.6%) showed bacterial growth and 164 isolates. Escherichia coli 45 (27.4%), Pseudomonas aeruginosa 38 (23.2%), and Staphylococcus aureus 38 (23.2%) were the most isolated. Among the Enterobacterales, 39/80 (48.8%) were extended-spectrum beta-lactamase producers. Methicillin-resistant Staphylococcus aureus was detected in 11/38 (29.0%) Staphylococcus aureus. Overall, multi-drug resistant strains were 127/164 (77.4%).Conclusions Gram-negative bacteria were the predominant cause of SSI. More than three-quarters of isolates were multi-drug-resistant strains. The findings underscore the need to regularly review antimicrobial prophylaxis practices and treatment guidelines, strengthen infection prevention and control measures, and antimicrobial stewardship.