The Effects of Antimicrobial Resistance and the Compatibility of Initial Antibiotic Treatment on Clinical Outcomes in Patients With Diabetic Foot Infection

Abstract

We aimed to determine pathogen microorganisms, their antimicrobial resistance patterns, and the effect of initial treatment on clinical outcomes in patients with diabetic foot infection (DFI). Patients with DFI from 5 centers were included in this multicenter observational prospective study between June 2018 and June 2019. Multivariate analysis was performed for the predictors of reinfection/death and major amputation. A total of 284 patients were recorded. Of whom, 193 (68%) were male and the median age was 59.9 ± 11.3 years. One hundred nineteen (41.9%) patients had amputations, as the minor (n = 83, 29.2%) or major (n = 36, 12.7%). The mortality rate was 1.7% with 4 deaths. A total of 247 microorganisms were isolated from 200 patients. The most common microorganisms were <i>Staphylococcus aureus</i> (n = 36, 14.6%) and <i>Escherichia coli</i> (n = 32, 13.0%). Methicillin resistance rates were 19.4% and 69.6% in <i>S aureus</i> and coagulase-negative <i>Staphylococcus</i> spp., respectively. Multidrug-resistant <i>Pseudomonas aeruginosa</i> was detected in 4 of 22 (18.2%) isolates. Extended-spectrum beta-lactamase-producing Gram-negative bacteria were detected in 20 (38.5%) isolates of <i>E coli</i> (14 of 32) and <i>Klebsiella</i> spp. (6 of 20). When the initial treatment was inappropriate, <i>Klebsiella</i> spp. related reinfection within 1 to 3 months was observed more frequently. Polymicrobial infection (<i>p</i> = .043) and vancomycin treatment (<i>p</i> = .007) were independent predictors of reinfection/death. Multivariate analysis revealed vascular insufficiency (<i>p</i> = .004), hospital readmission (<i>p</i> = .009), C-reactive protein > 130 mg/dL (<i>p</i> = .007), and receiving carbapenems (<i>p</i> = .005) as independent predictors of major amputation. Our results justify the importance of using appropriate narrow-spectrum empirical antimicrobials because higher rates of reinfection and major amputation were found even in the use of broad-spectrum antimicrobials.