| 食品动物源产CTX-M-14大肠杆菌传播分子机制的演变 |
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| 引用本文： | 甄盼盼,汤电,任艳娜,郭玉芳,王丽华,裘宗平,蒋红霞.食品动物源产CTX-M-14大肠杆菌传播分子机制的演变[J].中国畜牧兽医,2012,39(9):195-202. |
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| 作者姓名： | 甄盼盼 汤电 任艳娜 郭玉芳 王丽华 裘宗平 蒋红霞 |
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| 作者单位： | 华南农业大学兽医学院,广东省兽药研制与安全评价重点实验室,广东广州 510642 |
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| 基金项目： | 国家自然科学基金—广东省自然科学基金联合基金重点项目 |
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| 摘 要： | 从保存的2002-2009年分离的食品动物源大肠杆菌中,挑选16株blaCTX-M-14阳性菌,用PCR方法检测超广谱β-内酰胺酶(ESBLs)编码基因、PMQR耐药基因及其他重要抗生素耐药基因(rmtB和floR);通过脉冲场凝胶电泳(PFGE)及种族进化关系分析16株细菌的亲缘关系;通过接合转移试验、复制子分型和blaCTX-M-14上下游插入元件的检测,分析产CTX-M-14大肠杆菌的传播分子机制。PCR检测结果表明,16株食品动物源产CTX-M-14大肠杆菌大多属于系统发育组A组,其次为B1和D组,没有B2组;PFGE分型结果表明,同一时间内不同动物间存在产CTX-M-14共生型大肠杆菌克隆的扩散传播,但养殖场内CTX-M-14主要是随质粒或其他元件进行水平传播;质粒复制子分型结果表明,携带blaCTX-M-14的质粒属于IncK(3/14)、 IncF(5/14)、 IncHI2(1/14)、IncFIB 和 IncF(1/14)、IncHI1和IncN(2/14)、 IncI1(2/14)等,且随着时间推移,复制子的种类呈增多趋势。2002-2007年的菌株blaCTX-M基因的上下游均检测到ISEcp1和IS903;但2009年菌株除了部分在上下游都可以检测到ISEcp1和IS903外,还有的只检测到上游的ISEcp1或下游的IS903;2002-2009年的菌均未检测到ISCR1。16株产CTX-M-14大肠杆菌除了携带其他ESBLs编码基因,如blaCTX-M79和blaTEM-135外,还携带其他重要抗生素耐药基因,如oqxA、floR、aac(6')-1b-cr及rmtB,而且2002-2009年大肠杆菌携带耐药基因的种类和数量逐年增多;接合转移试验发现,2002-2005年的菌株,blaCTX-M-14往往发生单独转移,而2009年分离菌blaCTX-M-14往往和floR或rmtB位于同一质粒上发生共同转移。这说明养殖场使用氨基糖苷类或氟苯尼考等任何一种抗生素,都可以筛选出产CTX-M-14大肠杆菌并促进其扩散,所以动物养殖过程中要慎用这些抗生素。
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| 关 键 词： | CTX-M-14 传播分子机制 复制子分型 水平传播 |
| 收稿时间： | 2011-03-13 |
Evolutionally Dissemination of CTX-M-14 Producing Escherichia coli among Food-producing Animals |
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| ZHEN Pan-pan
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TANG Dian
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REN Yan-na
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GUO Yu-fang
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WANG Li-hua
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QIU Zong-ping
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JIANG Hong-xia.Evolutionally Dissemination of CTX-M-14 Producing Escherichia coli among Food-producing Animals[J].China Animal Husbandry & Veterinary Medicine,2012,39(9):195-202. |
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| Authors: | ZHEN Pan-pan TANG Dian REN Yan-na GUO Yu-fang WANG Li-hua QIU Zong-ping JIANG Hong-xia |
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| Institution: | Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine,South China Agricultural University,Guangzhou 510642,China |
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| Abstract: | Sixteen CTX-M-14 producing Escherichia coli isolates from food animal recovered from 2002 to 2009 were subjected to detection of extended spectrum beta-lactamases (ESBLs) encoding genes,plasmid mediated quinolone resistance determinants,and other relevant resistant genes (rmtB and floR); strains typing using PFGE and phylogrouping; blaCTX-M-14 plasmid replicon typing,transferring of blaCTX-M-14 by conjugation,and detection of context of blaCTX-M-14 gene. Majority of 16 isolates were clonally unrelated by PFGE,suggesting horizontally transfer of blaCTX-M-14 among food animals,and corresponded to phylogenetic groups A (50%),D (21.5%) and B1 (28.5%). Plasmids containing blaCTX-M-14a were belonging to IncK (n=3),IncHI2 (n=1),IncHI1 and IncN (n=2),IncFIB and IncF (n=1),IncF (n=5),or IncI1 (n=1),with insertion sequence of ISEcp1 upstream blaCTX-M-14a,and apparently increased in numbers of replicon and diversity from 2002 to 2009. The increasing dissemination of blaCTX-M-14 among different food-producing animals is mostly mediated by IncK,IncF,IncHI2,IncI1 plasmids carried by commensal E.coli. Some of CTX-M-14-producing E.coli harbored simultaneously blaCTX-M-79 or blaTEM-135, as well other relevant resistant genes,such as oqxA, floR, aac(6')-1b-cr or rmtB. BlaCTX-M-14 could be transferred separately in isolates of 2002,while co-transferred with other relevant resistant genes on the same plasmid via conjugation or transformation,suggesting co-selection and spread of CTX-M-14 producing isolates when use of any of the relevant antibiotics in animal farms. |
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| Keywords: | CTX-M-14 molecular mechanism of transmission replicon typing horizontal transmission |
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