Bacteria isolates and antimicrobial resistance patterns in burn wound infections: a cross-sectional study at two hospitals

Bacterial infections continue to be a significant complication and cause of morbidity and mortality in burn patients. To determine the bacterial species and antimicrobial resistance profiles of pathoges isolated from burn wound infections. A hospital-based cross-sectional study was conducted from January to June 2021 at Yekatit 12 Hospital Medical College and Addis Ababa Burn, Emergency, and Trauma Hospital. Wound swabs were processed immediately in the microbiology laboratory by culture, biochemical tests, and Gram staining. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method following Clinical and Laboratory Standards Institute (CLSI) guidelines. Of 240 specimens submitted, 147 (61.3%) were culture-positive and yielded 154 bacterial isolates. 110 (71.4%) were Gram-positive, while 44 (28.6%) were Gram-negative. Coagulase-negative Staphylococcus (CoNS) (n = 55, 22.9%) and Staphylococcus aureus (S. aureus) (n = 54, 22.4%) were the most commonly isolated Gram-positive bacteria, whereas Pseudomonas aeruginosa (P. aeruginosa) (n = 17, 7.1%) was the predominant Gram-negative isolate. S. aureus showed resistance to penicillin (n = 54/54, 100%) and chloramphenicol (n = 49/54, 90.7%). P. aeruginosa demonstrated 47% resistance (n = 8/17) to ceftazidime, and all isolates were susceptible to amikacin and meropenem. Klebsiella species (n = 5/5) were resistant to all antibiotics tested, including ceftazidime, gentamicin, ampicillin, tobramycin, ciprofloxacin, and chloramphenicol. Gram-positive bacteria, predominantly CoNS and S. aureus, were most common pathogens involved in burn wound infection at our study site. A high level of resistance to the antibiotics frequently used in our healthcare institutions was observed (notably 100% penicillin resistance in S. aureus and multidrug resistance among Klebsiella spp.). We recommend routine local surveillance of burn-wound pathogens and formal antimicrobial stewardship measures to guide empiric prescribing. The use of convenience sampling, small counts for some species, and single time point sample collection limits generalizability; therefore, larger prospective surveillance studies are needed.