Bacterial profile and antimicrobial susceptibility patterns of wound infections in Derna City, Libya

Abstract

Background: Wound infections represent a significant challenge particularly when caused by multidrug-resistant (MDR) bacteria. Methods: This cross-sectional study investigated the bacterial profile, antimicrobial susceptibility patterns and risk factors associated with wound infection in Derna City, Libya from 1 July to 30 December 2025. Wound swabs from various wound types were processed to identify bacterial isolates using standard microbiology techniques including culture, Gram stain and biochemical tests. Antimicrobial resistance patterns were identified using the Kirby – Bauer disc diffusion method according to the Clinical and Laboratory Standards Institute guidelines. An isolate was classified as MDR if resistance to at least one antimicrobial agent in at least three antimicrobial classes. Statistical analysis was performed and a P -value < 0.05 was considered statistically significant. Results: 130 swab samples were processed, and all samples yielded bacterial growth. Gram-positive isolates represented 68.5% (n = 89) while Gram-negative isolates accounted for 31.5% (n = 41). Bacterial species isolated from wound samples included Staphylococcus aureus (n = 89), Pseudomonas aeruginosa (n = 23), Klebsiella spp. (n = 10), Escherichia coli (n = 4), Proteus mirabilis (n = 2), a single isolate of Serratia liquefaciens and a single isolate of Acinetobacter baumannii . Antibiotics that showed the highest resistance among S. aureus isolates included clindamycin (73.0%), amoxicillin-clavulanic acid (67.4%), and co-trimoxazole (59.6%). Antibiotics that showed the highest susceptibility among S. aureus isolates include ciprofloxacin 56.2%, gentamicin 50.6% and doxycycline 47.2%. Gram-negative isolates displayed higher resistance to co-trimoxazole (88.9%), amoxicillin-clavulanic acid (82.4%), cefotaxime (77.8%), and gentamicin (73.2%). Resistance rates lower than 50% were observed to the carbapenems meropenem (48.8%), and imipenem (41.5%). MDR was identified in 89 of 130 isolates (68.5%). No significant association was observed between MDR status and most demographic or clinical variables. Conclusion: These findings indicate a substantial antimicrobial resistance burden and support local antimicrobial resistance surveillance and culture-guided treatment.