Efflux pumps expression and its association with porin down-regulation and beta-lactamase production among Pseudomonas aeruginosa causing bloodstream infections in Brazil.
Efflux pumps expression and its association with porin down-regulation and beta-lactamase production among Pseudomonas aeruginosa causing bloodstream infections in Brazil.
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DOI：
10.1186/1471-2180-10-217
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发表时间：
2010-08-12
期刊：
影响因子：
4.2
通讯作者：
Gales AC
中科院分区：
文献类型：
--
作者：
Xavier DE;Picão RC;Girardello R;Fehlberg LC;Gales AC
多药外排泵越来越被认为是铜绿假单胞菌耐药的主要组成部分。我们研究了铜绿假单胞菌临床分离株中外排系统的表达水平，而不考虑其抗菌敏感性。氨曲南对铜绿假单胞菌的敏感性最高（64.4%），而亚胺培南和美罗培南的敏感性均为47.5%。MexXY-OprM和MexAB-OprM外排系统分别在50.8%和27.1%的分离株中过表达。未观察到MexEF-OprN和mexd - oprj系统的过表达。AmpC β-内酰胺酶在11.9%的铜绿假单胞菌中过表达。此外，69.5%的标本和87.1%的亚胺培南不敏感铜绿假单胞菌临床分离株的oprD表达均下降。在铜绿假单胞菌分离株中分别检测到23.7%和1.7%的mbl编码基因blaSPM-1和blaIMP-1。在5.1%的分离株中检出blaGES-1, 1.7%的分离株中检出blaGES-5和blaCTX-M-2。在目前的研究中，我们观察到外排系统代表了抗菌素耐药性的辅助机制。在铜绿假单胞菌临床分离株的多重耐药表型中，与不同机制相关的外排系统（如孔蛋白下调、AmpC过量产生和次级β-内酰胺酶）也发挥了重要作用。
Multi-drug efflux pumps have been increasingly recognized as a major component of resistance in P. aeruginosa. We have investigated the expression level of efflux systems among clinical isolates of P. aeruginosa, regardless of their antimicrobial susceptibility profile. Aztreonam exhibited the highest in vitro activity against the P. aeruginosa isolates studied (64.4% susceptibility), whereas susceptibility rates of imipenem and meropenem were both 47.5%. The MexXY-OprM and MexAB-OprM efflux systems were overexpressed in 50.8% and 27.1% of isolates studied, respectively. Overexpression of the MexEF-OprN and MexCD-OprJ systems was not observed. AmpC β-lactamase was overexpressed in 11.9% of P. aeruginosa isolates. In addition, decreased oprD expression was also observed in 69.5% of the whole collection, and in 87.1% of the imipenem non-susceptible P. aeruginosa clinical isolates. The MBL-encoding genes blaSPM-1 and blaIMP-1 were detected in 23.7% and 1.7% P. aeruginosa isolates, respectively. The blaGES-1 was detected in 5.1% of the isolates, while blaGES-5 and blaCTX-M-2 were observed in 1.7% of the isolates evaluated. In the present study, we have observed that efflux systems represent an adjuvant mechanism for antimicrobial resistance. Efflux systems in association of distinct mechanisms such as the porin down-regulation, AmpC overproduction and secondary β-lactamases play also an important role in the multi-drug resistance phenotype among P. aeruginosa clinical isolates.
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影响因子：
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