Microbial Profile and Antibiotic Susceptibility Pattern in Diabetic Patients with Mild, Moderate, and Severe Foot Infections in Tehran

It is estimated that ۱۰-۲۵% of diabetic patients will encounter diabetic foot ulcers (DFU) during their lifetime. This study evaluated the microbiology of DFUs and determined the antibiotic resistance pattern of bacterial isolates based on the severity of wounds and infections in different grades of ulcer. The specimens were collected from۱۱۵ diabetic foot infections (DFI) deep tissue by needle aspiration and biopsy. The aerobic and anaerobic cultures and antimicrobial susceptibility testing were carried out. The presence of resistance genes including Metallo-beta-lactamases (MBL), extended-spectrum β-lactamase (ESBL), ermA, ermC, and mecA was also determined. A total of ۲۲۲ microorganisms were isolated. The prevalence of poly-microbial infections was ۶۹.۶%. Bacterial isolates comprised ۶۴.۲% Gram-positive bacteria (GPB), ۳۳.۵% Gram-negative bacteria (GNB), and five isolates of anaerobic bacteria were also detected. The most prevalent GPB and GNB were Staphylococcus spp. (۵۲.۲%) and Escherichia coli (۳۳.۳%), respectively. The prevalence of poly-microbial infections and GNB was positively associated with increased grades of Wagner and IDSA classifications. Among Staphylococcus aureus isolates, resistance to clindamycin (۷۳.۵%), ciprofloxacin (۷۰.۶%), and erythromycin (۷۰.۶%) were noticeable. GNB was also highly resistant to cephalosporins and ciprofloxacin. ESBL genes were detected in approximately ۴۰% of isolates of Enterobacteriaceae. The prevalence of Erma, ermC, and mecA genes in S. aureus isolates were ۸.۸%, ۳۲.۳%, and ۱۴.۷%, respectively. In conclusion, our data suggest that GPBs are the most common isolates from DFIs. Furthermore, with the development of wounds and infection, the prevalence of GNB in DFIs are increased.

Keywords:

Foot infections , antimicrobial resistance , S. aureus , ESBL