Distribution, antibiotic resistance and metabolic factors of pathogenic bacteria in diabetic foot infection: an analysis based on 286 patients in Chongqing

Abstract

Objective To investigate the characteristics and antibiotic resistance of pathogens in patients with diabetic foot infection (DFI) and to analyze the metabolic factors for the progression of foot disease. Methods A total of 286 DFI patients admitted in our department from January, 2013 to July, 2019 were recruited in this study. After tissue specimens were harvested from deep part of infected skin lesions under aseptic condition, the obtained microorganisms were identified and antimicrobial susceptibility tests were carried out. According to Wagner classification standard, the DFI patients were divided into mild and severe DFI groups. Characteristics and drug resistance of pathogenic bacteria and clinical biochemical indexes were analyzed and compared between the 2 groups. Spearman analysis was used to evaluate the correlation between clinical variables and disease progression. Logistic regression analysis was employed to identify the risk factors for exacerbation. Results There were 420 strains of microorganisms isolated from the 268 patients (268/286, 93.71%), including Staphylococcus aureus (21.90%), Pseudomonas aeruginosa (8.81%), and Enterococcus faecalis (6.67%). About 14.13% of Staphylococcus aureus were methicillin-resistant Staphylococcus aureus (MRSA). All the Enterococcus faecalis strains were multidrug resistant (MDR) strains. As for Klebsiella pneumoniae and Escherichia coli, nearly 10 (43.48%) and 10 (50.00%) strains were extended spectrum β-lactamases (ESBLs)-producing bacteria, respectively. The severe DFI group had significantly higher ratios of polymicrobial Gram-negative bacteria and MDR Gram-negative bacteria infections, and increased levels of neutrophils percentage (NEUT%), procalcitonin (PCT), and C-reactive protein (CRP)(all P < 0.05), but had obviously lower body mass index (BMI), decreased albumin (ALB), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and hemoglobin (Hb), and reduced toe brachial index (TBI) (all P < 0.05) when compared with the mild DFI group. Spearman analysis showed that the DFI severity was positively correlated with PCT, white blood cell count (WBC), NEUT%, CRP and TC (P < 0.05), while negatively correlated with TBI, ALB, triglyceride (TG), HDL-C and Hb (P < 0.05). Logistic regression analysis revealed that high TC level was associated with the exacerbation of foot lesion (OR=2.136, 95%CI: 1.352~3.372, P=0.001). Conclusion Polymicrobial Gram-negative bacteria and MDR Gram-negative bacteria are prevalent in severe DFI patients in Chongqing. PCT, WBC, NEUT%, CRP, TBI, ALB, Hb, TC, TG and HDL-C are important factors associated with foot lesion.

Keywords

• diabetic foot
• pathogen
• antibiotic resistance
• metabolic factor