The diabetic foot ulcer: Biofilm, antimicrobial resistance, and amputation

Background Diabetes mellitus is a major global health crisis, significantly increasing the risk of complications such as diabetic foot ulcers (DFUs). DFUs are critical as they can lead to infections, gangrene, amputations, and even death. Objective This research seeks to ascertain the prevalence of aerobic bacterial isolates in DFUs, specifically distinguishing between biofilm-producing and non-biofilm-producing strains. Methods This prospective cohort study at IIMS&R (August 2022-January 2024) involved adults with diabetes and DFUs, excluding gestational diabetes or non-diabetic ulcers. Ethical approval and informed consent were obtained. Clinical evaluations included medical history, physical exams, and Meggit-Wagner ulcer classification. Specimens were collected via debridement and the Levine swab technique for gram-staining and culture. Results The study involved 100 patients, predominantly male (81%), with type 2 diabetes mellitus (T2DM) and ulcers graded 1-4. Key findings include a high prevalence of neuropathy (77%), retinopathy (70%), and hypertension (41%). Most patients (89%) had poor glycaemic control (HbA1c > 7%). Bacterial infections were classified as superficial, subcutaneous, osteomyelitis, or forefoot gangrene, with 57% of patients having monomicrobial infections and 35% having polymicrobial infections. Among the 140 bacterial isolates identified, Gram-negative bacilli were predominant (78.6%). Escherichia coli (17.8%) was the most common isolate, followed by Staphylococcus aureus (15%). High antibiotic resistance was observed, especially in E. coli, which showed complete resistance to fluoroquinolones. Biofilm production was noted in 53.6% of isolates, with a significant association between biofilm producers (BFP), male sex (p = 0.004, OR 10.72, CI 2.4-53.71), and duration of ulcers (p = 0.028, OR 0.26, CI 0.08-0.86). Pseudomonas aeruginosa was the most prominent biofilm producer among Gram-negative bacteria. Conclusion This study emphasises the crucial role that biofilm development plays in DFUs, making treatment more difficult and emphasising the necessity of focused treatments to overcome antibiotic resistance linked to biofilm formation in DFUs.