ANTIMICROBIAL SUSCEPTIBILITY PATTERNS IN DIABETIC FOOT ULCERS AT A TERTIARY CARE TEACHING HOSPITAL IN SOUTH INDIA

Abstract

Background: Diabetic foot ulcers (DFUs) are a major complication of diabetes mellitus, frequently leading to severe infection, prolonged hospitalisation, and increased risk of amputation. Understanding local microbial profiles and antimicrobial susceptibility patterns is essential for guiding empirical therapy and antimicrobial stewardship. This study evaluated the antimicrobial susceptibility patterns of pathogens isolated from DFUs at a tertiary care teaching hospital in South India. Methods: We retrospectively analysed 100 patients with culture-proven diabetic foot infections treated at Saveetha Medical College and Hospital, Chennai, over a one-year period from January 2023 to January 2024. Demographic, clinical, microbiological, and antimicrobial susceptibility data were extracted from hospital records. Susceptibility testing was performed using the Kirby-Bauer disk diffusion method and interpreted according to CLSI guidelines. Results: A total of 150 microbial isolates were obtained from 100 patients; polymicrobial infection was noted in 25% of cases. The predominant organisms were Staphylococcus aureus (30%), Pseudomonas aeruginosa (25%), Escherichia coli (20%), and Klebsiella pneumoniae (15%). S. aureus showed high resistance to penicillin (85%) and methicillin (40%) but remained largely sensitive to vancomycin (95%) and linezolid (90%). P. aeruginosa showed significant resistance to ciprofloxacin (60%) and ceftazidime (50%) but was largely sensitive to piperacillin-tazobactam (85%) and meropenem (80%). E. coli and K. pneumoniae showed resistance to third-generation cephalosporins (70% and 60%, respectively) but remained largely sensitive to carbapenems (90% for both). Most patients (80%) showed clinical improvement with appropriate antimicrobial therapy, 10% required surgical intervention, and mortality was 5%. Conclusion: Multidrug-resistant organisms were common among pathogens isolated from DFUs in this cohort. Empirical antibiotic selection guided by local susceptibility patterns, supported by ongoing microbial surveillance and antimicrobial stewardship, is essential for improving outcomes and limiting further resistance in diabetic foot infections.