Aminoglycoside efflux in Pseudomonas aeruginosa:: Involvement of novel outer membrane proteins
Aminoglycoside efflux in Pseudomonas aeruginosa:: Involvement of novel outer membrane proteins
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DOI：
10.1128/aac.47.3.1101-1111.2003
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发表时间：
2003-03-01
影响因子：
4.9
通讯作者：
Hancock, REW
中科院分区：
文献类型：
--
作者：
Jo, JTH;Brinkman, FSL;Hancock, REW
在铜绿假单胞菌中，三方多药外排泵如MexA-MexB-OprM的表达有助于对多种抗菌剂的内在耐药性，包括β-内酰胺类、氯霉素、大环内酯类、喹诺酮类和四环素。MexX-MexY连接体-泵组合已被证明参与对氨基糖苷类的内在耐药性，但同源外膜通道组分的身份仍在争论中。通过评估缺乏相应基因的铜绿假单胞菌菌株PAK敲除突变体中氨基糖苷类的最小抑制浓度（MIC），检查了在铜绿假单胞菌基因组中鉴定的14个未表征的OprM同源物作为该作用的候选物。OpmG、OpmI和OpmH的插入失活导致链霉素、卡那霉素和庆大霉素的MIC不同程度降低。当在多拷贝质粒上重新引入铜绿假单胞菌时，OpmG能够补充opmG：：miniTn 5突变体的易感性;然而，克隆的opmH，根据我们的系统发育分析提出的大肠杆菌tolC的直系同源物，只能部分补充opmH。miniTn 5突变体。微型微阵列杂交分析表明，opmG中断不影响表达的OpmI或OpmH（排除这种间接影响氨基糖苷类耐药），然而，opmH中断确实有可能影响的表达的OpmG和OpmI。基于这些数据，我们提出OpmG是铜绿假单胞菌PAK中参与氨基糖苷类外排的主要外膜外排通道，并且OpmI，其最相关的paraffin，可能具有重叠的功能。
The expression of tripartite multidrug efflux pumps such as MexA-MexB-OprM in Pseudomonas aeruginosa contributes to intrinsic resistance to a wide variety of antimicrobials, including beta-lactams, chloramphenicol, macrolides, quinolones, and tetracycline. The MexX-MexY linker-pump combination has been shown to be involved in intrinsic resistance to aminoglycosides, but the identity of the cognate outer membrane channel component remains under debate. Fourteen uncharacterized OprM homologs identified in the genome of P. aeruginosa were examined as candidates for this role by assessing the minimum inhibitory concentrations (MICs) of aminoglycosides in P. aeruginosa strain PAK knockout mutants lacking the corresponding genes. Insertional inactivation of OpmG, OpmI, and OpmH resulted in decreases of various degrees in the MICs of streptomycin, kanamycin, and gentamicin. When reintroduced into P. aeruginosa on multicopy plasmids, OpmG was able to complement the susceptibility of an opmG::miniTn5 mutant; however, cloned opmH, the proposed ortholog of Escherichia coli tolC according to our phylogenetic analysis, was able to only partially complement the opmH.:miniTn5 mutant. Mini-microarray hybridization analysis demonstrated that opmG disruption does not affect expression of OpmI or OpmH (ruling out such indirect effects on aminoglycoside resistance); however, opmH disruption did have possible effects on expression of OpmG and OpmI. Based on the data, we propose that OpmG is a major outer membrane efflux channel involved in aminoglycoside efflux in P. aeruginosa PAK and that OpmI, its most related paralog, may share an overlapping function.