Microbial etiology of diabetic foot ulcers: Swab versus tissue culture

Abstract

Introduction: Diabetic foot infection is limb threatening condition among patients suffering from diabetes. Choosing suitable antibiotic against particular pathogen to treat diabetic foot infection is most critical step in preventing further consequences such as amputation. The present study aimed to determine consensus and degree of difference between the two methods of collecting wound specimens by comparing the pathogens isolated from the same wound from each method. Materials and Methods: This was a prospective, observational study in which a total of 77 patients with infected diabetic wound seen both inpatient and outpatient department of surgery. Wagner’s method was used to classify diabetic foot ulcers. Samples were collected by two methods, superficial swab (Levine’s method) and tissue sample. Results: A total of 79 bacteria were isolated from 77 patients. Out of 79 bacteria, 68 were isolated from swabs and 77 were from tissue samples. Isolation rate of Gram positive bacteria was differed in type of sample. Tissue specimens showed high yield than swab. But no difference was observed in isolation rate of Gram negative bacteria based on type of sample collected. Conclusion: In our study, tissue culture was found to be the most acceptable technique in identifying the microbial etiology of limb threatening diabetic foot infections.