Bacterial etiology of diabetic foot infections in South India

Abstract

Background: Foot infections are a frequent complication of patients with diabetes mellitus, accounting for up to 20% of diabetes-related hospital admissions. Infectious agents are associated with the worst outcomes, which may ultimately lead to amputation of the infected foot unless prompt treatment strategies are ensued. The present study sought to reveal the bacterial etiology of diabetic foot ulcers in South India, the diabetic capital of India.

Methods: A 10-month-long descriptive study was carried out to analyse the aerobic and anaerobic bacterial isolates of all patients admitted with diabetic foot infections presenting with Wagner grade 2-5 ulcers. Bacteriological diagnosis and antibiotic sensitivity profiles were carried out and analysed using standard procedures.

Results: Diabetic polyneuropathy was found to be common (56.8%) and gram-negative bacteria (57.6%) were isolated more often than gram-positive ones (42.3%) in the patients screened. The most frequent bacterial isolates were Pseudomonas aeruginosa, Staphylococcus aureus, coagulase-negative staphylococci (CONS), and Enterobacteriaceaes. Forty-nine cultures (68%) showed polymicrobial involvement. About 44% of P. aeruginosa were multi-drug-resistant, and MRSA was recovered on eight occasions (10.3%). Bacteroides spp. and Peptostreptococcus spp. were the major anaerobic isolates.

Conclusions: Our study supports the viewpoint put forth by previous South Indian authors that the distribution of gram-negative bacteria (57.6%) is more common than that of gram-positive ones (42.3%) and it is contrary to the viewpoint that diabetic foot infections are frequently monomicrobial. Furthermore, recovery of multi-drug-resistant P. aeruginosa isolates is of serious concern, as almost no one has reported the same from the South Indian milieu.