Abstract
Aim: This study evaluated the incidence and factors responsible for plasmid-mediated extended-spectrum beta-lactamase (ESBL) infection among patients with diabetic foot ulcer (DFU).
Subjects and Methods: A prospective study was conducted on 162 DFU inpatients treated in a multidisciplinary-based diabetes and endocrinology center at Jawaharlal Nehru Medical College of Aligarh Muslim University, Aligarh, India, during the period of December 2008-March 2011. Detailed history and patient's profile, grade of DFU, co-morbidities and complications, laboratory data, and final outcome were collected. Standard methods were used for culture identification, sensitivity testing, and ESBL detection. Polymerase chain reaction for bla genes was performed, and the risk factors for bla gene positivity were determined by univariate analysis with 95% confidence interval.
Results: In total, 127 (78.3%) Enterobacteriaceae members were isolated. The most common isolate was Escherichia coli (71; 55.9%), followed by Klebsiella sp. (33; 25.9%) and Proteus sp. (13; 10.2%). By phenotypic methods, 67.8% were ESBL producers. In the molecular detection of ESBLs, 81.9% were found to be positive for the bla gene, of which bla(CTX-M) showed 81.8% positivity, followed by bla(TEM) (50%) and bla(SHV) (46.9%). In a univariate analysis, bla gene-positive status was associated with low-density lipoprotein-cholesterol (> 100 mg/dL) (P < 0.004, odds ratio 13.4, relative risk 8.65) and triglycerides (> 200 mg/dL) (P < 0.003, odds ratio 6.5, relative risk 4.11).
Conclusion: ESBL constitutes a major threat to currently available beta-lactam therapy, leading to complications in DFUs. Aminoglycosides, cephalosporin, and beta-lactam inhibitor drugs would probably be more appropriate empirical agents after establishing the patient's history of previous antibiotic use. The detection of ESBL should be done on a routine basis.