Microbiology and Antimicrobial Resistance Profile in Patients with Diabetic Foot Sepsis at a Central Hospital in Johannesburg, South Africa

Diabetic foot sepsis (DFS) is the leading cause of lower extremity amputations and timely initiation of effective antimicrobial therapy is paramount during its management. This study investigated causative microorganisms and their antimicrobial susceptibility profile in patients with DFS. Methods: A retrospective review was conducted on patients who were 18-years and older admitted for DFS. . Data collected included demographic: information, comorbidities, clinical findings, type of specimen collected for microbiology and microbiology results, treatment and outcomes. Data was analysed using STATA/SE version 17.0 and a p-value of 0.05 considered statistically significant. Results: Hundred and sixty-eight records were found of which 64.3% of patients were male who also had a median (IQR) age of 58 years (IQR 54-65). In comparison, females had a median age of 61 years (IQR 54-67). The microbiology results were available in 63.1% of the records and 60.4% were taken from tissue specimens (60.4%) and 14.2% from pus swabs (14.2%). Enterococcus faecalis was cultured in 16%, Proteus mirabilis 10%, and Staphylococcus aureus in 8%. Amoxicillin/Clavulanic acid was prescribed for 69% of the cases. Resistance to at least one antimicrobial was observed in 88% of Staphylococcus aureus and 80% of Proteus mirabilis species. Conclusions: Diabetic foot sepsis commonly affects males around the age of 60 years. The commonly cultured organism in patients with DFS are Enterococcus faecalis 16%, Proteus mirabilis 10%, and Staphylococcus aureus. Amoxicillin/Clavulanic acid as the primary antimicrobial therapy and in close to 40% of patients, with DFS, antimicrobial treatment is not preceded by collection of a specimen for MC&S despite high rates of resistance seen in the common cultured organisms. This data may assist with updating local guidelines so as to better manage this condition in an evidenced based way.