Prevalence and Antimicrobial Susceptibility of Bacterial Isolates in Diabetic Foot Ulcers: A Comparative Study of Povidone Iodine vs. Normal Saline Dressings

Abstract

Background and Aims: Diabetic foot ulcers (DFUs) are a major complication of diabetes mellitus, often complicated by bacterial infections leading to prolonged healing and increased amputation risk. This study aimed to assess the prevalence and antimicrobial susceptibility of bacterial isolates in DFUs and compare the efficacy of povidone iodine versus normal saline dressings on wound healing.
Materials and Methods: A prospective study was conducted at GMKMCH, Salem, from 2021 to 2023, involving 100 diabetic patients with non-healing DFUs. Pus and wound swabs were collected for aerobic culture and antibiotic susceptibility testing. Patients were randomized into two groups: Group I (povidone iodine dressing) and Group II (normal saline dressing). Wound healing was assessed using the modified Perfusion, Extent, Depth, Infection, Sensation (PEDIS) scoring system. Statistical analysis was performed using SPSS version 24.
Results: Of 100 samples, 90 yielded aerobic bacterial growth, with Staphylococcus aureus (18.4%) and Proteus species (23.2%) being the most common isolates. Polymicrobial infections were observed in 31% of cases. Povidone iodine dressings resulted in a 27.2% wound reduction score compared to 13.9% for normal saline (p=0.001). Gram-negative isolates showed high sensitivity to piperacillin-tazobactam (100% for Proteus), while S. aureus exhibited 55% methicillin resistance.
Conclusion: Povidone iodine dressings significantly improved wound healing compared to normal saline in DFU patients. The high prevalence of methicillin-resistant S. aureus (MRSA) and multidrug-resistant Gram-negative bacteria underscores the need for targeted antimicrobial therapy and effective wound care strategies.