A Retrospective Study of Infections and Antibiotic Susceptibility in Diabetic Foot Ulcers

This study aimed to investigate the predominant pathogenic microorganisms, antimicrobial resistance patterns, and antibiotic sensitivity profiles of diabetic foot infections in the southern region of a province in central-eastern China, thereby providing evidence-based guidance for the rational use of antibiotics for treating foot infections in patients with diabetes.

A retrospective analysis was performed on the clinical data from patients with diabetic foot infections who were treated at a large tertiary hospital between 1 July 2019 and 31 July 2024. Wound specimens were collected for bacterial culture and antimicrobial susceptibility testing, and both clinical and microbiological data were analyzed.

A variety of pathogenic microorganisms, predominantly Gram-positive (G⁺) and Gram-negative (G^-) bacteria, were isolated. The top five pathogens identified were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus agalactiae (group B), and Proteus mirabilis. As the Wagner grade increased, there was a shift in pathogens from G⁺ to G^- bacteria, along with a rise in polymicrobial infections, primarily coinfections involving G⁺ and G^- bacteria. The G⁺ bacteria exhibited high resistance to penicillin and certain cephalosporins but remained highly sensitive to vancomycin and linezolid. G^- bacteria showed increased resistance to quinolones, carbapenems, and aminoglycosides while maintaining relative sensitivity to tigecycline and polymyxins. Fungal infections were highly sensitive to commonly used antifungal agents. Overall, significant variations in resistance to antimicrobials were observed among different strains, with some exhibiting notable multidrug resistance, underscoring the high risk of empirical monotherapy.

The issue of antimicrobial resistance in foot infections associated with diabetes mellitus is becoming increasingly severe. Clinical treatment should be guided by antimicrobial susceptibility testing to ensure rational antibiotic use, improve therapeutic outcomes, reduce the emergence of resistant bacteria, and lower recurrence rates.