Study of Plasmid-Mediated Extended-Spectrum β-Lactamase-Producing Strains of Enterobacteriaceae, Isolated from Diabetic Foot Infections in a North Indian Tertiary-Care Hospital

Mohammad Zubair, Abida Malik, Jamal Ahmad
2012 Diabetes Technology & Therapeutics  
Aim: This study evaluated the incidence and factors responsible for plasmid-mediated extended-spectrum blactamase (ESBL) infection among patients with diabetic foot ulcer (DFU). Subjects and Methods: A prospective study was conducted on 162 DFU inpatients treated in a multidisciplinarybased diabetes and endocrinology center at 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
more » ... ere 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 b-lactam therapy, leading to complications in DFUs. Aminoglycosides, cephalosporin, and b-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. and anaerobes (Bacteroides sp. and Peptostreptococcus sp.). [3][4][5][6] Enterobacteriaceae are an important pathogenic group in community and hospital-acquired infections, and resistance to antibiotics has become increasingly common. The most serious emerging problem is resistance to Gram-negative organisms, including resistance to extended-spectrum cephalosporins and penicillin, among the diabetic foot ulcer (DFU) isolates. 3,6-9 Extended-spectrum b-lactamases (ESBLs) capable of degrading the extended-spectrum cephalosporins and monobactams are the most relevant determinants of resistance On average, 74.2% of Gram-negative DFU isolates were positive in the screening of ESBL by the disc diffusion method: 142 (85.0%) isolates were positive using cefotaxime, followed by 127 (76.0%) for cefpodoxime, 117 (70.0%) for aztreonam, and 116 (69.4%) for ceftriaxone and ceftazidime each. In the confirmatory ESBL test, 67.8% were found to be positive by the disc potential method: 132 (79%) using cefoperazone/ cefoperazone + sulbactam, followed by 126 (75.4%) by piperacillin/piperacillin + tazobactum, and 114 (68.2%) by cefotaxime/cefotaxime + clavulanic, whereas ceftazidime/ ceftazidime + clavulanic acid showed only 81 (48.5%) produced ESBL (Table 4) . Occurrence of bla genes The frequency of bla genes in DFU isolates is shown in Table 4 . Only the E. coli and Klebsiella sp. resistant to cefotaxime were subjected to Class A (CTX-M, TEM, and SHV) ESBL study. On average, 89.3% cefotaxime-resistant isolates were found positive for bla genes, of which CTX-M was found to be the most prevalent ESBL noted in 54 (81.8%), followed ESBL IN DIABETIC FOOT ULCER 317 Data are mean -SD values or n (%) unless otherwise indicated. CI, confidence interval; Hb, hemogloblin; HbA1c, glycated hemoglobin; HDL-C, high-density lipoprotein-cholesterol; LDL-C, low-density lipoprotein-cholesterol; OR, odds ratio; RR, relative risk; SGOT/AST, serum glutamic oxaloacetic transaminase/aspartate transaminase; SGPT/AST, serum glutamate-pyruvate transaminase/aspartate transaminase; WBC, white blood cells. Abstract The present study was undertaken to study the difference in antibiotic resistance profile and minimum antibiotic concentration (MIC) of biofilm producing and non-biofilm producing gram-negative bacilli isolated from diabetic foot ulcer ( DFU) patients in a tertiary care hospital in North India. Among the diabetic foot patients, 73.6% were males and 15% were females. 77.1% had T2DM whereas only 24.4% patients had T1DM. Poor glycemic control and poor HbA1c (>8) was observed in 68.7% and 70.1% patients respectively. Among the 57 patients, 97 gramnegative bacilli were isolated in which mixed bacterial infection was found in 67.8% and monomicrobial in 32.2% only. Escherichia coli was the most common (42.2%) isolate followed by Pseudomonas aeruginosa (23.7%), Klebsiella oxytoca (11.3%), Klebsiella pneumonia (9.2%), Proteus vulgaris (5.1%), Acinetobacter sp (5.1%), Proteus mirabilis (2%) and Morganella morganii (1.0%). 77.1% DFU patients had infection by biofilm producing organisms. BFP positive status was associated with the presence of neuropathy (O.R. 7.65), osteomyelitis (O.R. 3.14), duration of ulcer (O.R. 25.7), grade of ulcer (O.R. 9.12), necrotising ulcer (O.R. 14.4) and ulcer size >4cm 2 (O.R. 3.30) but not with patients characteristic, type of diabetes and type of diabetes, or duration of hospital stay. Poor glycemic control in 56.1% patients, amputation (24.5%), hospital stay (38.5%) and age distribution were independently associated with risk of biofilm producing infection in diabetic foot patients.
doi:10.1089/dia.2011.0197 pmid:22225456 fatcat:lvm52fx5u5flvkvv7o5wjyzehi