Kiratisin Pattarachai, Apisarnthanarak Anucha, Laesripa Chaitat, Saifon Piyawan
Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, 2 Prannok Rd., Bangkok-Noi, Bangkok 10700, Thailand.
Antimicrob Agents Chemother. 2008 Aug;52(8):2818-24. doi: 10.1128/AAC.00171-08. Epub 2008 May 27.
Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae have rapidly spread worldwide and pose a serious threat for health care-associated (HA) infection. We conducted molecular detection and characterization of ESBL-related bla genes, including bla(TEM), bla(SHV), bla(CTX-M), bla(VEB), bla(OXA), bla(PER), and bla(GES), among 362 isolates of ESBL-producing E. coli (n = 235) and ESBL-producing K. pneumoniae (n = 127) collected from patients who met the definition of HA infection at two major university hospitals in Thailand from December 2004 to May 2005. The prevalence of ESBL-producing E. coli and ESBL-producing K. pneumoniae, patient demographics and the susceptibilities of these bacteria to various antimicrobial agents were described. A total of 87.3% of isolates carried several bla genes. The prevalence of bla(CTX-M) was strikingly high: 99.6% for ESBL-producing E. coli (CTX-M-14, -15, -27, -40, and -55) and 99.2% for ESBL-producing K. pneumoniae (CTX-M-3, -14, -15, -27, and -55). ISEcp1 was found in the upstream region of bla(CTX-M) in most isolates. Up to 77.0% and 71.7% of ESBL-producing E. coli and ESBL-producing K. pneumoniae, respectively, carried bla(TEM); all of them encoded TEM-1. ESBL-producing K. pneumoniae carried bla(SHV) at 87.4% (SHV-1, -2a, -11, -12, -27, -71, and -75) but only at 3.8% for ESBL-producing E. coli (SHV-11 and -12). bla genes encoding VEB-1 and OXA-10 were found in both ESBL-producing E. coli (8.5% and 8.1%, respectively) and ESBL-producing K. pneumoniae (10.2% and 11.8%, respectively). None of the isolates were positive for bla(PER) and bla(GES). Pulsed-field gel electrophoresis analysis demonstrated that there was no major clonal relationship among these ESBL producers. This is the first study to report CTX-M-3, CTX-M-27, CTX-M-40, SHV-27, SHV-71, and SHV-75 in Thailand and to show that CTX-M ESBL is highly endemic in the country.
产超广谱β-内酰胺酶（ESBL）的大肠埃希菌和肺炎克雷伯菌已在全球迅速传播，对医疗保健相关（HA）感染构成严重威胁。我们对从2004年12月至2005年5月在泰国两家主要大学医院符合HA感染定义的患者中分离出的362株产ESBL的大肠埃希菌（n = 235）和产ESBL的肺炎克雷伯菌（n = 127）进行了与ESBL相关的bla基因的分子检测和特征分析，这些bla基因包括bla(TEM)、bla(SHV)、bla(CTX-M)、bla(VEB)、bla(OXA)、bla(PER)和bla(GES)。描述了产ESBL的大肠埃希菌和产ESBL的肺炎克雷伯菌的流行情况、患者人口统计学特征以及这些细菌对各种抗菌药物的敏感性。总共87.3%的分离株携带几种bla基因。bla(CTX-M)的流行率极高：产ESBL的大肠埃希菌中为99.6%（CTX-M-14、-15、-27、-40和-55），产ESBL的肺炎克雷伯菌中为99.2%（CTX-M-3、-14、-15、-27和-55）。在大多数分离株中，ISEcp1存在于bla(CTX-M)的上游区域。分别高达77.0%的产ESBL的大肠埃希菌和71.7%的产ESBL的肺炎克雷伯菌携带bla(TEM)；它们均编码TEM-1。产ESBL的肺炎克雷伯菌携带bla(SHV)的比例为87.4%（SHV-1、-2a、-11、-12、-27、-71和-75），而产ESBL的大肠埃希菌中仅为3.8%（SHV-11和-12）。在产ESBL的大肠埃希菌（分别为8.5%和8.1%）和产ESBL的肺炎克雷伯菌（分别为10.2%和11.8%）中均发现了编码VEB-1和OXA-10的bla基因。所有分离株均未检测到bla(PER)和bla(GES)呈阳性。脉冲场凝胶电泳分析表明，这些产ESBL菌之间没有主要的克隆关系。这是泰国首次报告CTX-M-3、CTX-M-27、CTX-M-40、SHV-27、SHV-71和SHV-75，并表明CTX-M型ESBL在该国高度流行。
