Antimicrobial susceptibility and mechanism of quinolone resistance in Campylobacter jejuni strains isolated from diarrheal patients in a hospital in Tokyo
Antimicrobial susceptibility and mechanism of quinolone resistance in Campylobacter jejuni strains isolated from diarrheal patients in a hospital in Tokyo
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DOI：
10.1007/s10156-008-0631-2
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发表时间：
2008-10-01
影响因子：
2.2
通讯作者：
Okamura, Noboru
中科院分区：
文献类型：
--
作者：
Bakeli, Gulibahaer;Sato, Kenya;Okamura, Noboru
我们确定了6种类型的抗菌药物的最低抑菌浓度为523株空肠弯曲菌，分离自2003年至2005年期间在东京的综合医院的腹泻患者。结果表明，在所有的C.测试的空肠菌株分别对环丙沙星（CPFX）、萘啶酸、氨苄青霉素和磷霉素具有抗性。所有菌株均对克拉霉素和红霉素敏感。为阐明喹诺酮类药物耐药机制，对随机抽取的55株大肠埃希菌gyrA和gyrB基因的喹诺酮类药物耐药决定区（QRDRs）进行了序列测定和分析。37株CPFX耐药株均存在GyrA基因第86位密码子的氨基酸替换（Thr → IIe）。gyrB基因的QRDR中没有氨基酸替换。这55个菌株的基因组DNA都显示出不同的脉冲场凝胶电泳图谱。综合以上结果，提示C.空肠弯曲菌GyrA基因QRDR区第86位密码子突变（Thr → IIe）是导致该突变的主要原因，该突变及其它沉默突变不仅存在于空肠弯曲菌的某个克隆中，也存在于空肠弯曲菌的其它克隆中。空肠，但也普遍存在于各种菌株中。
We determined the minimum inhibitory concentrations of six types of antimicrobial agents for 523 strains of Campylobacter jejuni that were isolated from diarrheal patients in a general hospital in Tokyo during the period between 2003 and 2005. It was revealed that 20.2%, 22.9%, 6.7%, and 0.6% of all the C. jejuni strains tested were resistant to ciprofloxacin (CPFX), nalidixic acid, ampicillin, and fosfomycin, respectively. All the strains were susceptible to clarithromycin and erythromycin. To elucidate the mechanism of quinolone resistance, in a total of 55 strains selected randomly, we carried out sequence determination and analysis of the quinolone-resistance determining regions (QRDRs) of their gyrA and gyrB genes. Amino-acid substitution at codon 86 (Thr -> IIe) of GyrA was found in all the 37 CPFX- resistant strains. There was no amino-acid substitution in the QRDR of the gyrB gene. All of the genomic DNAs of these 55 strains showed distinct pulsed-field gel electrophoresis patterns. Taken together, these results suggested that the quinolone resistance of C. jejuni was attributable mainly to the mutation at codon 86 (Thr -> IIe) in the QRDR of GyrA, and that this particular mutation and other silent mutations could be found not only in a certain clone of C. jejuni but also universally in a wide variety of strains.