Phenotypic and Antibiogram Profile of Bacteria Isolated from Diabetic Foot Ulcers

Background: Diabetic foot ulcers (DFUs) represent a severe complication of diabetes mellitus, frequently progressing to infections that challenge clinical management and increase amputation risks. This study aims to characterize the bacterial etiology and antimicrobial resistance patterns of DFU isolates in Libyan patients. Material and Methods: From March to June 2024, 39 wound samples were collected from DFU patients at Abu Salim Trauma Hospital, Tripoli. Wound sites were cleansed with sterile saline, and samples were cultured aerobically for bacterial isolation using standard bacteriological media. Bacterial identification and antimicrobial susceptibility testing were performed using automated systems (BD Phoenix M50 and MA120 Render). Statistical analyses assessed associations between demographic factors (e.g., age, sex), ulcer severity, and microbial profiles. Results: Of 39 samples, 17 yielded pathogenic bacterial isolates (24 culture-positive, with 7 excluded as contaminants), with Gram-negative bacteria predominating (76.5%). Pseudomonas aeruginosa (35%) and Staphylococcus aureus (23%) were the most common. Three isolates (17.6%) exhibited multidrug resistance (MDR), defined as non-susceptibility to at least one agent in three or more antimicrobial classes, including one carbapenem-resistant P. aeruginosa (CRPA) and two methicillin-resistant S. aureus (MRSA). Gram-negative dominance was associated with severe ulcer grades (p = 0.03 ). Age (>60 years; OR = 3.2, p = 0.03 ) and ulcer severity (OR = 4.8, p = 0.01 ) predicted MDR phenotypes. Conclusion: The presence of MDR pathogens in DFUs shows the need for enhanced surveillance, antibiotic stewardship, and tailored therapeutic strategies in Libya to improve patient outcomes and combat resistance.