Abstract
INTRODUCTION: Diabetic foot infection (DFI) represents a growing public health problem in Africa, caused by several microorganisms, with Staphylococcus aureus being one of the most prevalent pathogens associated with subsequent complications. This study aimed to characterize S. aureus isolated from the wounds of patients with type 2 diabetes, treated at a health center in Beira, Mozambique, in terms of antibiotic resistance and virulence genes. METHODS: Samples were collected by swab, after ulcer debridement, and cultivated onto mannitol salt Columbia agar supplemented with 5% sheep blood, for 24 to 48 h, at 37°C. The antibiotic resistance was assessed by disk diffusion on Mueller-Hinton agar, and Multiplex PCR was used to screen 32 virulence and seven antibiotic resistance genes. RESULTS: S. aureus isolates showed high phenotypic resistance to penicillin (100%), cefoxitin (53.3%), trimethoprim/sulfamethoxazole (40%) and vancomycin (22.2%), and a high percentage of multidrug resistance (68.9%). The most prevalent resistance genes were blaZ (penicillin, 100%), mecA (cefoxitin, 53.3%) and vancA (vancomycin, 28.9%). The most frequent virulence genes were TSST (toxic syndrome staphylococcal toxin, 57.8%), and the colonization factor clfB (37.8%), followed by the Panton-Valentine leukocidin (PLV) genes, lukPV (26.7%) and lukED (15.6%). The regulator factor coded by arcA (37.8%) and the adhesion factors coded by cap5 (20%) and by icaA (17.8%) were also found. CONCLUSION: A high presence of virulence genes encoding exotoxins and colonization and adhesion factors, associated with a high rate of multidrug resistance, was found in S. aureus isolates. This anticipates increasing difficulty in treating DFI. The greatest resistance was to commonly used antibiotics, particularly penicillin, cefoxitin and vancomycin, with resistance genes, blaZ, mecA and vancA, frequently detected. This emphasizes the urgent need for improved antimicrobial stewardship, routine molecular surveillance, and improved management strategies for DFI in resource-limited settings to mitigate disease complications and reduce the burden of antimicrobial resistance.