β-lactamase characterization in Escherichia coli isolates with diminished susceptibility or resistance to extended-spectrum cephalosporins recovered from sick animals in Spain
β-lactamase characterization in Escherichia coli isolates with diminished susceptibility or resistance to extended-spectrum cephalosporins recovered from sick animals in Spain
复制标题
DOI：
10.1089/107662903765826804
复制
发表时间：
2003-06-01
期刊：
影响因子：
--
通讯作者：
Torres, C
中科院分区：
文献类型：
--
作者：
Briñas, L;Moren, MA;Torres, C
从1997年至2001年，从西班牙兽医抗菌素耐药性监测网络（VAV）共收到1439株病畜大肠杆菌分离株。进行了抗菌药敏试验，分别有2.5%和2.8%的分离株对头孢噻肟和头孢他啶的敏感性降低。对具有这两种特征的20株大肠杆菌进行了β -内酰胺酶鉴定。这20株分离株的不同β -内酰胺类药物的MIC范围（单位：马克杯/毫升）为：氨苄西林（64- >56）、阿莫西林-克拉维酸（4-64）、替卡西林（8- >28）、头孢唑林（32- >56）、头孢西丁（4- >28）、头孢噻肟（1-64）、头孢他啶（2->64）、头孢曲松（0.5-64）、亚胺培南（小于等于0.06-0.25）、氨曲南（2->32）。对TEM、SHV、CMY和FOX β -内酰胺酶基因进行PCR和测序分析。检测到的β -内酰胺酶基因为：bla(TEM-1b)(3)、bla(TEM-1a)(1)、bla(TEM-30f)(2)、bla(TEM-1b) + bla(CMY-2)(2)、bla(SHV-12)(1)。研究了20株ampC基因启动子和/或衰减子区的序列。在16株分离株中检测到-42或-32位点突变，这些突变与6株分离株中TEM型β -内酰胺酶的存在有关。此外，还检测到多种质粒β -内酰胺酶，包括TEM-30和CMY-2。据我们所知，这是首次在动物源性大肠杆菌分离株中检测到TEM-30 β -内酰胺酶。
A total of 1439 Escherichia coli isolates from sick animals were received from the Spanish Network of Veterinary Antimicrobial Resistance Surveillance (VAV) from 1997 to 2001. Antimicrobial susceptibility tests were performed and diminished susceptibility to cefotaxime and ceftazidime was identified in 2.5% and 2.8% of the isolates, respectively. beta-lactamase characterization was carried out in the group of 20 E. coli isolates with both characteristics. The MIC ranges of different beta-lactams showed by these 20 isolates were as follows (in mug/ml): ampicillin (64->256), amoxicillin-clavulanic acid (4-64), ticarcillin (8->128), cefazolin (32->256), cefoxitin (4->128), cefotaxime (1-64), ceftazidime (2->64), ceftriaxone (0.5-64), imipenem (less than or equal to0.06-0.25), and aztreonam (2->32). TEM, SHV, CMY, and FOX beta-lactamase genes were analyzed by PCR and sequencing. The beta-lactamase genes detected were the following ones (number of isolates): bla(TEM-1b) (3), bla(TEM-1a) (1), bla(TEM-30f) (2), bla(TEM-1b) + bla(CMY-2) (2), and bla(SHV-12) (1). Sequences of the promoter and/or attenuator region of the chromosomal ampC gene were studied in all the 20 isolates. Mutations at position -42 or -32 were detected in 16 isolates and these mutations were associated with the presence of a TEM type beta-lactamase in 6 isolates. Besides, a high variety of plasmidic beta-lactamases was detected including TEM-30 and CMY-2. To our knowledge, this is the first time that TEM-30 beta-lactamase has been detected in E. coli isolates of animal origin.