造成肝膿瘍大腸桿菌的菌株分析

近幾年，許多報導可從大腸桿菌的質體發現 AmpC βlactamase﹐而且與腸內菌一樣對大多數 β-lactam 有抗藥性，甚至對 cephamycin 和 β-lactam inhibitor 有抗藥性，故與 Extended-Spectrum Beta-Lactamases (ESBLs)可做區分。 本研究菌株來自國立成功大學醫學院附設醫院細菌室所分離出來的大腸桿菌，收集時間為 2002 年 ~ 2010 年，來自於肝膿瘍病人所分離培養出之大腸桿菌共計 24 株，分別進行以下之檢測：藉由 Double disk synergy test 和 Disk diffusion confirmatory test 傳統 phenotype 篩選有 ESBL 的大腸桿菌比率為 8.3 % (2/24)。 以Polymerase chain reaction(PCR)分析大腸桿菌相關抗藥基因：TEM type 比率45.8% (11/24)，CMY-2 type 比率為 20.8 % (5/24)，CXM type 比率為 12.5% (3/24)。 利用核酸序列定序發現 blaCTX-M 基因存在 3 種 subtypes，blaCTX-M-3、blaCTX-M-14、blaCTX-M-15 基因，其中以 blaCTX-M-3 和 blaCTX-M-14 最為常見。Determination of the Escherichia coli Phylogenetic Group 可將大腸桿菌分為 4 型：A、B1、B2、D。 並使用脈衝式電泳分析法 Pulsed-field gel electrophoresis(PFGE)及多重基因座序列分型法 Multilocus sequence typing(MLST)於大腸桿菌菌株基因的分型，24 株大腸桿菌可被分為 23 脈衝式電泳分析法，但僅可分為 16 MLST 型。本研究結果顯示在肝膿瘍大腸桿菌中發現具有 ESBL、TEM type、CTX-M type 及 CMY-2 的 AmpC β-lactamase 的菌株。

Recently, many research indicate that the plasmids isolated from Escherichia coli include AmpC β-lactamase gene. The function of AmpC is resistant against the β-lactam antibiotics, just the same as the other enterobacteriaceae. Because β-lactam resistant Escherichia coli also resistant against cephamycin and β-lactam inhibitor antibiotics. Thus, it can different from Extended-Spectrum Beta-Lactamases ( ESBLs ). In this study, the Escherichia coli strains collected from the bacteria lab department of pathology National Cheng- Kung university hospital. The collect interval is AD 2002-2010. Total 24 Escherichia coli strains isolated from liver abscess patients. Testing by Double disk synergy test and Disk diffusion confirmatory test. The result is Escherichia coli ( ESBL ) phenotype ratio is 8.3% (2/24). Then analyze genes associated Escherichia coli metabolic enzymes by Polymerase chain reaction ( PCR ). Result: The ratio of TEM type is 45.8% (11/24). The ratio of CMY-2 type is 20.8% (5/24). The ratio of CXM type is 12.5% (3/24). By sequnecing﹐blaCTX-M have 3 subtypes including blaCTX-M-3、blaCTX-M-14、blaCTX-M-15. The most common is blaCTX-M-3 and blaCTX-M-14. The phylogenetic typing of 24 strains can divided into four types: A, B1, B2 and D. Farther, typing by Pulsed-field gel electrophoresis ( PFGE ) and Multilocus sequence typing ( MLST ), the 24 strains can divided into 23 PFGE types and 16 MLST types. In this study indicate that Escherichia coli with AmpC β-lactamase isolated from liver abscess could type into ESBL、TEM typing、CTX-M typing and CMY-2 typing.