An Analysis of Bacterial Isolates from Pus Culture Versus Tissue Culture in Diabetic Foot Infection Through Amit Jain’s Classification for Diabetic Foot Complications

Aim: To compare pus culture versus tissue culture for bacterial isolates of diabetic foot infections through Amit Jain’s classification for diabetic foot.

Materials and methods: A retrospective comparative analysis was done at Amit Jain’s Institute of Diabetic foot and Wound Care, BrindhavvanAreion hospital, Bengaluru. The study period was from Jan 2019 to June 2020. Statistical Analysis was done using SPSS version 25.0 and p value of < 0.05 was considered significant.

Results: 42 patients were included in this study. Tissue culture yielded bacteria in 90.5% of cases. Pus culture had multiple growths in 9.5% whereas tissue culture had multiple growths in 16.7%. In both pus and tissue cultures, Gram negative organisms were common compared to Gram positive and E coli was commonest isolate in both. No difference was seen in type 1 and type 3 diabetic foot complications in regards to number and type of bacterial isolates in pus culture. Whereas in tissue culture, significant difference was noted wherein type 1 diabetic foot complication had more Gram positive organisms and type 3 diabetic foot complications had Gram negative organisms. In type 1 diabetic foot complications, pus culture had 77% sensitivity and 100% specificity and was comparable to tissue culture.

Conclusion: Tissue culture was found to have higher yield and higher percentage of multiple organisms compared to pus culture. However, in type 1 diabetic foot complications like abscess, wet gangrene, necrotizing fasciitis, etc,one can rely on swab culture as its yields were comparable with tissue culture. We believe that pus culture is a reasonable choice for bacterial isolate in diabetic foot complications.