Distribution and Antibiotic Resistance Characteristics of Pathogenic Bacteria in Chronic Wound Infections: A Five-Year Retrospective Study at a Tertiary Hospital

Objective: This study aimed to characterize the microbial profiles and antibiotic resistance patterns of predominant pathogens in chronic wounds, with the ultimate goal of optimizing evidence-based antimicrobial therapy to improve wound healing outcomes. Methods: Clinical data and microbial specimens (wound secretions, blood and urine) were collected from patients admitted to the Burns Department of the Second Affiliated Hospital of Kunming Medical University (January 2019–December 2023). Bacterial identification and antibiotic susceptibility testing were performed via standard microbiological methods and interpreted per CLSI guidelines. Statistical analyses were conducted via SPSS 27.0 and WHONET 5.6. Results: Among the 784 pathogenic isolates, gram-negative bacteria predominated (53.32%), followed by gram-positive bacteria (43.62%) and fungi (3.06%). The most prevalent pathogens were Staphylococcus aureus (52.05%), Escherichia coli (23.68%), Enterobacter cloacae (14.83%), and Pseudomonas aeruginosa (13.64%). Multidrug-resistant (MDR) strains accounted for 16.8%, with methicillin-resistant S. aureus (MRSA) representing 66.67% of MDR isolates. Resistance to ciprofloxacin, gentamicin, and levofloxacin increased significantly over time ( P < 0.05). Conclusion: Staphylococcus aureus is the most prevalent pathogen in chronic wounds, and the presence of multidrug-resistant bacteria complicates treatment, increasing resistance to empiric antibiotics. Tailored antimicrobial therapy on the basis of local resistance patterns is critical for effective management. Keywords: chronic wound infections, antimicrobial resistance, microbial sensitivity tests, multidrug-resistant bacteria, retrospective study