Microbial spectrum, antibiotic susceptibility profile, and biofilm formation of diabetic foot infections (2014-18): a retrospective multicenter analysis

This study identifies the risk factors, microbiological properties, antimicrobial susceptibility patterns, mortality, and clinical complications associated with organisms causing diabetic foot infections (DFIs) with or without antibiotic treatment using data from a retrospective multicenter surveillance. Specimens collected from different hospitals were cultured and the extended-spectrum β-lactamase (ESBL) excretion was estimated. The antibacterial susceptibility pattern and biofilm formation were completed along with the recommended standard methods. Overall, 792 diabetic foot patients (DFPs) were enrolled and a total of 1803 causative organisms were isolated. Polymicrobial infection was identified in 48.5% of the patients. The isolated Gram-positive pathogens (46.7%) were higher than Gram-negative (38.6%) or anaerobes (7.9%). The predominant pathogens were S. aureus (22.2%), methicillin-resistant S. aureus (7.7%), Enterococcus spp. (12.8%), Pseudomonas aeruginosa (9.4%), E. coli (7.9%), Klebsiella spp. (7.5%), Proteus mirabilis (8.9%), coagulase negative staphylococci (CoNS) (6.6%), anaerobic organisms (5.9%), and fungi (2.3%). Vancomycin and clindamycin exhibited no activity against Gram-positive bacteria. However, meropenem and imipenem displayed high activity against the Gram-negative isolates. Out of the 765 tested strains, 251 showed moderate (15.8%) to high (34%) level biofilm-producing phenotype. DFIs were widespread among the diabetic patients with different microbial etiology and the major organisms were aerobic organisms. Our findings may provide an insight into the development of appropriate therapeutic strategies for the management of DFIs.