Characterization of CTX-M-14-producing Escherichia coli from food-producing animals.
Characterization of CTX-M-14-producing Escherichia coli from food-producing animals.
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DOI：
10.3389/fmicb.2015.01136
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发表时间：
2015
影响因子：
5.2
通讯作者：
Jiang HX
中科院分区：
文献类型：
--
作者：
Liao XP;Xia J;Yang L;Li L;Sun J;Liu YH;Jiang HX
细菌对第三代头孢菌素类抗生素的耐药性已成为公共卫生的主要问题。目的研究广东省大肠埃希菌中编码超广谱β-内酰胺酶的blaCTX-M-14的特性和分布。共获得979株E.对分离自猪、禽等健康或患病食用动物的大肠埃希菌进行blaCTX-M-14检测，并对阳性菌株进行其他耐药决定因素（超广谱β-内酰胺酶基因、质粒介导的喹诺酮类耐药、rmtB和floR）检测，并进行系统发育聚类分析、基于PCR的质粒复制子分型、多位点序列分型和质粒分析。PCR检测blaCTX-M-14的遗传环境。结果表明，14株产CTX-M-14的E.大肠埃希菌属A群（7/14）、B1群（4/14）和D群（3/14）。最主要的抗性基因是blaTEM（n = 8），其次是floR（n = 7）、oqxA（n = 3）、aac（6′）-1b-cr（n = 2）和rmtB（n = 1）。携带blaCTX-M-14的质粒被分类为IncK、IncHI 2、IncHI 1、IncN、IncFIB、IncF或IncI 1，范围为约30至200 kb，并且具有位于blaCTX-M-14上游的ISEcp 1、IS 26或ORF 513和位于blaCTX-M-14下游的IS 903的插入序列。多位点序列分型结果表明，14个分离株共11个ST，分属于5个群。据报道，许多已鉴定的序列类型在E.大肠杆菌分离株与人类肠外感染相关，表明blaCTX-M-14可能在动物和人类之间传播。2009年分离株和早期分离株之间blaCTX-M-14侧翼序列的差异表明，耐药基因背景在大肠杆菌中继续进化。食用动物的大肠杆菌。
Bacterial resistance to the third-generation cephalosporin antibiotics has become a major concern for public health. This study was aimed to determine the characteristics and distribution of blaCTX-M-14, which encodes an extended-spectrum β-lactamase, in Escherichia coli isolated from Guangdong Province, China. A total of 979 E. coli isolates isolated from healthy or diseased food-producing animals including swine and avian were examined for blaCTX-M-14 and then the blaCTX-M-14 -positive isolates were detected by other resistance determinants [extended-spectrum β-lactamase genes, plasmid-mediated quinolone resistance, rmtB, and floR] and analyzed by phylogenetic grouping analysis, PCR-based plasmid replicon typing, multilocus sequence typing, and plasmid analysis. The genetic environments of blaCTX-M-14 were also determined by PCR. The results showed that fourteen CTX-M-14-producing E. coli were identified, belonging to groups A (7/14), B1 (4/14), and D (3/14). The most predominant resistance gene was blaTEM (n = 8), followed by floR (n = 7), oqxA (n = 3), aac(6′)-1b-cr (n = 2), and rmtB (n = 1). Plasmids carrying blaCTX-M-14 were classified to IncK, IncHI2, IncHI1, IncN, IncFIB, IncF or IncI1, ranged from about 30 to 200 kb, and with insertion sequence of ISEcp1, IS26, or ORF513 located upstream and IS903 downstream of blaCTX-M-14. The result of multilocus sequence typing showed that 14 isolates had 11 STs, and the 11 STs belonged to five groups. Many of the identified sequence types are reported to be common in E. coli isolates associated with extraintestinal infections in humans, suggesting possible transmission of blaCTX-M-14 between animals and humans. The difference in the flanking sequences of blaCTX-M-14 between the 2009 isolates and the early ones suggests that the resistance gene context continues to evolve in E. coli of food producing animals.