EVIDENCE FOR AN EFFLUX PUMP IN MULTIDRUG-RESISTANT CAMPYLOBACTER-JEJUNI
EVIDENCE FOR AN EFFLUX PUMP IN MULTIDRUG-RESISTANT CAMPYLOBACTER-JEJUNI
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DOI：
10.1128/aac.39.9.2019
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发表时间：
1995-09-01
影响因子：
4.9
通讯作者：
PECHERE, JC
中科院分区：
文献类型：
--
作者：
CHARVALOS, E;TSELENTIS, Y;PECHERE, JC
探讨空肠弯曲菌的耐药机制。通过在培氟沙星和头孢噻肟梯度平板上连续传代，分别获得了对培氟沙星耐药的突变株34 PEF（r）（细菌数增加128倍）和对头孢噻肟耐药的突变株34 CTX（r）（细菌数增加32倍）。这两种突变株对红霉素、氯霉素、四环素、β-内酰胺类和喹诺酮类抗生素具有交叉耐药性。虽然菌株PEF（r）的喹诺酮类耐药可以通过gyrA基因第86位密码子的突变来解释，但进一步研究了两种菌株的多药耐药表型。培氟沙星，环丙沙星和米诺环素的积累，通过荧光测定法测定，并发现在突变株低于在亲本菌株。预孵育的细胞与羰基氰间氯苯腙，但是，完全消除了这种差异。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳的外膜制剂从两个突变株的分析表明，两个蛋白质的55和39 kDa的野生型菌株的外膜是不存在的过表达。这些结果表明，在C.空肠34 PEF（r）和34 CTX（r）的多药耐药与具有广泛特异性的外排系统相关。
Mechanisms of drug resistance in Campylobacter jejuni were investigated. Mutant strains 34PEF(r), which was resistant to pefloxacin (128-fold increase in the MIG), and 34CTX(r), which was resistant to cefotaxime (32-fold increase in the MIG) and which was derived from the susceptible parent 34(s), were obtained by serial passages on pefloxacin and cefotaxime gradient plates, respectively. Both mutants showed cross-resistance to erythromycin, chloramphenicol, tetracycline, beta-lactams, and quinolones. While the quinolone resistance of strain PEF(r) could be explained by a mutation at codon 86 of the gyrA gene, the multidrug resistance phenotype of both strains was further investigated. Accumulation of pefloxacin, ciprofloxacin, and minocycline was measured by fluorometry and was found to be lower in the mutant strains than in the parent strain. Preincubation of the cells with carbonyl cyanide m-chlorophenylhydrazone, however, completely abolished this difference. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane preparations from both mutant strains showed overexpression of two proteins of 55 and 39 kDa which were absent from the outer membranes of the wild-type strain. These results indicate that in C. jejuni 34PEF(r) and 34CTX(r), multidrug resistance is associated with an efflux system with a broad specificity.