Incidence, Microbiological Agents, and Predictors of Surgical Site Infections Following Open Surgeries at Muhimbili National Hospital in Tanzania, Otorhinolaryngology Department: A Prospective Cohort Study

Background: Surgical site infection (SSI) is the most common complication encountered following surgery across all surgical disciplines, leading to prolonged hospital stays, readmissions, increased hospital-related expenses, reoperations, and even mortality. The incidence, microbial agents involved, and predictors specific to otorhinolaryngology open Surgeries remain largely unidentified. Methodology: This was a Prospective Cohort study, involving patients who had undergone open surgeries in the Otorhinolaryngology (ORL) department. Data were gathered using a structured data collection tool. Wound swabs were taken for microbiological analysis from clinical SSI cases after 30 days of follow-up. Analysis was done using STATA version 15.1. The Chi-square/Fisher’s exact test was used to determine the statistical significance of SSI occurrence. Modified Poisson regression analysis was employed to assess the strength of the relationship between independent and dependent variables. Results: The study enrolled 89 (100%) participants, 20 (22.5%) of whom developed SSI. About 95% (19/20) of the clinical SSI cases yielded culture-positive results, of which 72.2% of the isolated bacterial species were Gram-negatives, among which 1 (8.3%) was ESBL-positive. Pseudomonas aeruginosa 7 (38.9%) followed by Staphylococcus aureus 3 (16.7%) were the most isolated bacterial species. The majority of Pseudomonas aeruginosa species were highly resistant to ceftazidime but least resistant to ciprofloxacin, aztreonam, and piperacillin-tazobactam. All Staphylococcus aureus species isolated were MRSA- positive and multiply resistant to nearly all conventional antibiotics. In multivariable analysis, having an ASA score III (RR 3.62, 95% CI 1.13 - 11.54, P = 0.03) independently predicted the occurrence of SSI. Conclusion: The incidence of SSI in the Otorhinolaryngology department is high (22.5%), chiefly caused by Pseudomonas aeruginosa Species, which are sensitive to ciprofloxacin, piperacillin-tazobactam, and aztreonam, followed by Staphylococcus aureus, all MRSA-positive and multiply resistant to most conventional antibiotics. It was significantly predicted by a high ASA score (ASA III).