Phenotypic Characterization of Methicillin-Resistant Staphylococcus spp (MRS) Strains Isolated from Diabetic Foot Wounds at Yaounde Central Hospital

Abstract

Background: Diabetic foot infections are a major public health concern and are frequently complicated by multidrug-resistant bacteria. Staphylococci, particularly methicillin-resistant strains (MRS), are among the most commonly encountered pathogens. Aim: This study aimed to determine the prevalence of MRS in diabetic foot wounds, characterise their resistance profiles, and identify phenotypes associated with multidrug resistance. Methods: A cross-sectional study was conducted among 112 patients with diabetic foot wounds at Yaoundé Central Hospital between March and July 2021. Samples were analysed using culture, biochemical identification (API Staph), and disc-diffusion susceptibility testing. hVISA and GISA phenotypes were screened using the ROSCO method. Data were analysed using Epi InfoTM7 and Excel software, with statistical significance set at p < 0.05. MRS were detected in 60.71% (68/112) of samples. The highest resistance rates were observed for β-lactams (99.26%) and aminoglycosides (91.17%), whereas nitrofurantoin (97.08%) and rifampicin (79.4%) showed the highest susceptibility rates. Among the 68 isolates, 25 (36.76%) were multidrug-resistant to more than seven antibiotic families (p = 0.001). The most frequent species were S. hominis (28%), S. epidermidis (16%), and S. xylosus (16%). GISA (60%) and hVISA (36%) phenotypes were detected, and some strains were also resistant to daptomycin. Conclusion: Methicillin resistance in diabetic foot infections in Cameroon is not restricted to S. aureus but also involves clinically significant coagulase-negative staphylococci. These findings support expanded antimicrobial resistance surveillance and the adaptation of therapeutic protocols to local resistance patterns.