Bora Arijit, Hazarika Naba Kumar, Shukla Sanket Kumar, Prasad Kashi N, Sarma Jayanta Biswa, Ahmed Giasuddin
Department of Biotechnology, Gauhati University, Guwahati, Assam, India.
Indian J Pathol Microbiol. 2014 Apr-Jun;57(2):249-54. doi: 10.4103/0377-4929.134698.
This study was carried out to determine the presence of blaTEM , blaSHV and blaCTX-M genes in extended-spectrum β-lactamase (ESBL) producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) at a tertiary care referral hospital in Northeast India.
A total of 270 E. coli and 219 K. pneumoniae isolates were recovered during the period between August 2009 and July 2010. Kirby-Bauer disk diffusion method was performed to determine the antibiotic resistance pattern. Screening and phenotypic confirmatory test for ESBL production were performed using standard disc diffusion methods. Each of the initial ESBL screening test isolate was investigated for the presence of blaTEM , blaSHV and blaCTX-M genes via polymerase chain reaction (PCR) using gene-specific primers.
Phenotypic confirmatory test able to detect ESBL production in 73.58% of E. coli and 67.24% of K. pneumoniae. However, PCR amplification showed the presence of one or more ESBL genes in each of the initial ESBL screening positive isolate. Among three ESBL genotypes, the most prevalent genotype was found to be blaCTX-M in E. coli (88.67%) and blaTEM in K. pneumoniae (77.58%) ESBL producing isolates. Majority of ESBL producing isolates possess more than one ESBL genes.
This study constituted a primer report on high prevalence of blaTEM and blaCTX-M genes in ESBL producing isolates of E. coli and K. pneumoniae and denotes the need of more extensive studies on these antibiotic genes to determine the magnitude of the problem of antibiotic resistance exiting in this locality.
本研究旨在确定印度东北部一家三级转诊医院中产超广谱β-内酰胺酶（ESBL）的大肠埃希菌（大肠杆菌）和肺炎克雷伯菌中blaTEM、blaSHV和blaCTX-M基因的存在情况。
在2009年8月至2010年7月期间共分离出270株大肠杆菌和219株肺炎克雷伯菌。采用 Kirby-Bauer 纸片扩散法确定抗生素耐药模式。使用标准纸片扩散法进行ESBL产生的筛选和表型确证试验。通过聚合酶链反应（PCR）使用基因特异性引物对每个初始ESBL筛选试验分离株进行blaTEM、blaSHV和blaCTX-M基因存在情况的研究。
表型确证试验能够检测出73.58%的大肠杆菌和67.24%的肺炎克雷伯菌产生ESBL。然而，PCR扩增显示每个初始ESBL筛选阳性分离株中都存在一个或多个ESBL基因。在三种ESBL基因型中，在产ESBL的大肠杆菌分离株中最常见的基因型是blaCTX-M（88.67%），在产ESBL的肺炎克雷伯菌分离株中是blaTEM（77.58%）。大多数产ESBL的分离株拥有不止一个ESBL基因。
本研究构成了关于产ESBL的大肠杆菌和肺炎克雷伯菌分离株中blaTEM和blaCTX-M基因高流行率的初步报告，并表明需要对这些抗生素基因进行更广泛的研究，以确定该地区存在的抗生素耐药问题的严重程度。
