Molecular Characterization and Biofilm Dynamics of Multi-Drug-Resistant Bacterial Isolates from Kenyan Diabetic Foot Ulcers

Abstract Diabetic foot ulcers (DFUs) are a major complication of diabetes mellitus and are frequently complicated by infections caused by multidrug-resistant (MDR) bacteria, resulting in prolonged hospitalization, poor wound healing, and increased risk of lower-limb amputation. This study investigated the molecular resistance determinants, virulence characteristics, and antibiofilm activity of MDR bacterial isolates recovered from infected DFUs in Kisumu County, Kenya. A cross-sectional study was conducted between March and July 2025 among 471 patients attending three referral hospitals. Following bacterial isolation and antimicrobial susceptibility testing, nineteen MDR isolates were selected for phenotypic and molecular characterization. Virulence factor production, antibiofilm activity, and detection of mecA, blaCTX-M-1, blaSHV, blaTEM, and blaKPC genes were performed using standard microbiological and PCR-based methods. Five of nine (55.6%) Gram-positive MDR isolates produced at least one virulence factor, while five of ten (50.0%) Gram-negative isolates produced all virulence factors evaluated. All seven-virulence factor-producing isolates retained biofilm-forming ability despite partial inhibition by selected antibiotics. The mecA gene was detected in 55.6% Staphylococcus aureus isolates, whereas blaCTX-M-1 was identified in 60% Gram-negative isolates. One Acinetobacter baumannii isolate co-harbored blaCTX-M-1 and blaSHV, while blaTEM and bla < sub>KPC were not detected. These findings demonstrate the circulation of MDR pathogens carrying clinically important resistance determinants and virulence traits among patients with infected DFUs in western Kenya, underscoring the need for strengthened molecular surveillance, antimicrobial stewardship, and evidence-based management strategies.