Rao Sridhar Pn, Rama Prasad Subba, Gurushanthappa Vishwanath, Manipura Radhakrishna, Srinivasan Krishna
Department of Microbiology, JJM Medical College, Davangere, Karnataka, India.
Department of Microbiology, Sri Devaraj Urs Medical College, Kolar, Karnataka, India.
J Lab Physicians. 2014 Jan;6(1):7-13. doi: 10.4103/0974-2727.129083.
There are sporadic reports on detection of extended-spectrum beta-lactamases (ESBL) producers from Karnataka; hence, this is a first multicentric study across Karnataka state to determine the prevalence of ESBL production among clinical isolates of Escherichia coli and Klebsiella pneumoniae.
To determine the prevalence of ESBL producing clinical isolates of E. coli and K. pneumoniae from five geographically distributed centers across Karnataka, to study the susceptibility of ESBL producing isolates to other beta-lactam and beta-lactam-beta-lactamase inhibitors and to demonstrate transferability of plasmids coding for ESBL phenotype.
Two hundred isolates of E. coli and K. pneumoniae each were collected from each of the five centers (Bellary, Dharwad, Davangere, Kolar and Mangalore). They were screened for resistance to screening agents (ceftazidime, cefotaxime, ceftriaxone, aztreonam) and positive isolates were confirmed for ESBL production by test described by Clinical and Laboratory Standards Institute. Co-production of ESBL and AmpC beta-lactamase was identified by using amino-phenylboronic acid disk method. Susceptibility of ESBL producers to beta-lactam antibiotics and beta-lactamase inhibitors was performed. Transferability of plasmids was performed by conjugation experiment.
Overall prevalence of ESBL production among E. coli and K. pneumoniae across five centers of the state was 57.5%. ESBL production was found to be 61.4% among E. coli and 46.2% among K. pneumoniae. ESBL production was significantly more among E. coli than K. pneumoniae. Significant variations in distribution of ESBL across the state was observed among E. coli isolates, but not among K. pneumoniae isolates. All ESBL producers demonstrated minimum inhibitory concentration levels ≥2 μg/ml towards cefotaxime, ceftazidime and ceftriaxone.
Overall prevalence of ESBL production among clinical isolates of E. coli and K. pneumoniae across Karnataka state was high. The prevalence of ESBL production was significantly higher with E. coli than K. pneumoniae isolates. Higher rates of resistance to ceftriaxone and cefotaxime than to ceftazidime suggests the possibility of presence of CTX-M type ESBLs. Of all the beta-lactam/beta-lactamase inhibitor combinations tested, cefepime-tazobactam demonstrated highest in-vitro activity against ESBL producers. There was no statistical difference in the transferability of plasmids among E. coli and K. pneumoniae.
关于在卡纳塔克邦检测出产超广谱β-内酰胺酶（ESBL）菌株的报道较为零散；因此，这是卡纳塔克邦首次开展的一项多中心研究，旨在确定大肠杆菌和肺炎克雷伯菌临床分离株中ESBL的产生情况。
确定来自卡纳塔克邦五个地理分布中心的产ESBL的大肠杆菌和肺炎克雷伯菌临床分离株的流行情况，研究产ESBL分离株对其他β-内酰胺类和β-内酰胺-β-内酰胺酶抑制剂的敏感性，并证明编码ESBL表型的质粒的可转移性。
从五个中心（贝拉里、达尔瓦德、达万盖雷、科拉尔和芒格洛尔）各收集200株大肠杆菌和肺炎克雷伯菌分离株。对它们进行筛选剂（头孢他啶、头孢噻肟、头孢曲松、氨曲南）耐药性检测，阳性分离株通过临床和实验室标准协会描述的试验确认产ESBL。采用氨基苯硼酸纸片法鉴定ESBL和AmpCβ-内酰胺酶的共产生情况。检测产ESBL菌株对β-内酰胺类抗生素和β-内酰胺酶抑制剂的敏感性。通过接合试验检测质粒的可转移性。
该邦五个中心的大肠杆菌和肺炎克雷伯菌中ESBL产生的总体流行率为57.5%。大肠杆菌中ESBL产生率为61.4%，肺炎克雷伯菌中为46.2%。大肠杆菌中ESBL产生率显著高于肺炎克雷伯菌。在大肠杆菌分离株中观察到该邦ESBL分布存在显著差异，但在肺炎克雷伯菌分离株中未观察到。所有产ESBL菌株对头孢噻肟、头孢他啶和头孢曲松的最低抑菌浓度水平≥2μg/ml。
卡纳塔克邦大肠杆菌和肺炎克雷伯菌临床分离株中ESBL产生的总体流行率较高。大肠杆菌中产ESBL的流行率显著高于肺炎克雷伯菌分离株。对头孢曲松和头孢噻肟的耐药率高于头孢他啶，提示可能存在CTX-M型ESBLs。在所有测试的β-内酰胺/β-内酰胺酶抑制剂组合中，头孢吡肟-他唑巴坦对产ESBL菌株表现出最高的体外活性。大肠杆菌和肺炎克雷伯菌之间质粒的可转移性没有统计学差异。
