Diabetic foot infections: Profile and antibiotic susceptibility patterns of bacterial isolates in a tertiary care hospital of Oman

In diabetic foot infections (DFIs), the diversity of microbial profile and ever‑changing antibiotic‑resistance patterns emphasize accurate characterization of microbial profile and antibiotic susceptibility pattern. The aim of the study was to investigate the pathogens associated with DFI and their antibiotic susceptibility patterns.

A cross‑sectional retrospective study was conducted at a tertiary‑care hospital, Oman. The socio‑demographic and microbiological profile and antibiotic susceptibility patterns of pathogens isolated from patients with DFIs from January 2013 to December 2018 were reviewed. Quantitative and qualitative variables were expressed as mean ± standard deviation and percentages, respectively. A Chi‑square test was used for testing the association between multidrug‑resistant (MDR) organisms and variables.

In total, 233 isolates recovered from 133 clinical specimens with an average of 1.8 organisms per specimen were included in the study. Fifty‑six and forty-four percent of specimens showed monomicrobial and polymicrobial growth of two or more organisms, respectively. The frequency of isolation was predominant among males (65%). Aerobic Gram‑negative rods were predominantly (75%) isolated compared to Gram‑positive organisms (25%). Staphylococcus aureus and Pseudomonas aeruginosa were the most frequently isolated Gram‑positive and Gram‑negative bacteria, respectively. Thirty‑eight percent of them were MDR strains. Gram‑negative organisms showed fairly good susceptibility ranging from 75% to 100% to carbapenems, aminoglycosides, and piperacillin‑tazobactam. While doxycycline and trimethoprim‑sulfamethoxazole showed good susceptibility toward Gram‑positive organisms.

DFIs are often polymicrobial with a predominance of Gram‑negative pathogens. This study recommends the use of carbapenems and doxycycline for empirical therapy of Gram‑negative and Gram‑positive bacterial DFIs, respectively.