In Vitro Antibacterial Effect of Probiotics Against Bacterial Isolates from Diabetic Foot Ulcers in Ain Shams University Hospitals

Diabetic wound infections often develop as a result of multi-drug resistant (MDR) bacterial infections, creating a major therapeutic challenge. Probiotics are known to produce antimicrobial compounds with potential antibacterial effect. The aim of our study is to assess the antibacterial effect of different Lactobacillus strains against pathogens of diabetic foot ulcers (DFUs). 150 wound swabs were collected from inpatients and outpatients attending emergency room, Vascular Surgery and General Surgery Departments at Ain Shams University Hospitals who were suffering from DFUs. Bacterial isolates were identified by standard microbiological methods. The antibacterial activity of probiotics was assessed using well diffusion method. From the 150 wound swabs, 204 Gram-negative (GN) and Gram positive (GP) pathogens were isolated. Klebsiella species (spp.) were the most frequent bacteria (61; 29.9%) isolated from diabetic foot ulcers. Total carbapenem resistant (CR) isolates represented (64.9%). Lactobacillus plantarum exhibited notable antibacterial effects against both GN and GP isolates, the highest zone of inhibition (ZOIs) among GP was against staphylococcus aureus (17 mm), while, among GN was against Klebsiella spp. (9.23mm). Gram-positive bacteria were generally more susceptible than Gram-negative bacteria. Diabetic foot infections (DFIs) are commonly caused by GN-MDR pathogens, particularly Klebsiella spp., with a high prevalence of carbapenem resistance. Despite widespread antibiotic resistance, Lactobacillus cell free supernatant (CFS) exhibited inhibitory activity against both GP and GN isolates. These findings support the potential role of probiotics as an adjunct antimicrobial strategy, owing to its promising antibacterial effect, particularly against Gram-positive bacteria.