Bacteriology of moderate-to-severe diabetic foot infections in two tertiary hospitals of Iran

Abstract

Background: Approximately 25% of people with diabetes will experience diabetic foot ulcers (DFUs) during their lifetime. The present study was designed to determine the type of microorganisms isolated from the DFUs and their antibiotic resistance pattern, and to determine predisposing factors contributing to antibiotic resistance at the authors' wound care clinic in Qazvin, Iran.

Methods: A cross-sectional study was conducted from May to December 2017. One specimen for microbiological studies was obtained from the deep tissue. All demographic, clinical, and laboratory data and results of ulcer culture were collected for each case. Antimicrobial susceptibility testing to different agents was carried out using the disc diffusion method. A p value < 0.05 was considered significant.

Results: 95 aerobic microorganisms were isolated from 105 specimens. Among Gram-positive and negative bacteria, Staphylococcus spp. and Escherichia (E). coli were the most frequent organisms isolated, respectively. Multidrug resistant (MDR) organisms constituted up to 48.4%, with 37.5% of isolated Enterococcus spp. being VRE, 48.8% of Staphylococcus spp. being methicillin-resistant, 77.8% of isolated E. coli being ESBL and 66.7% of isolated Pseudomonas being MDR. The minimum and maximum prevalence of resistance in Gram-negative bacteria were 17.6% and 87.5% for imipenem and ceftazidime, respectively. The prevalence of Gram-negative bacilli was higher in older patients (p value = 0.039) and rose markedly in patients with a higher number of hospitalizations (p value = 0.015).

Conclusion: Due to emergence of antibiotic resistance pathogens, culture specimens and antibiotic sensitivity testing are essential for correct management of the DFU infections and the selection of appropriate antibiotics.

Keywords: Antibiotics; Diabetic foot; Infections; Microbiology.