Multidrug efflux pumps:: Expression patterns and contribution to antibiotic resistance in Pseudomonas aeruginosa biofilms
Multidrug efflux pumps:: Expression patterns and contribution to antibiotic resistance in Pseudomonas aeruginosa biofilms
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DOI：
10.1128/aac.45.6.1761-1770.2001
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发表时间：
2001-06-01
影响因子：
4.9
通讯作者：
Storey, DG
中科院分区：
文献类型：
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作者：
De Kievit, TR;Parkins, MD;Storey, DG
铜绿假单胞菌生物膜对抗菌化疗具有内在抗性。目前，很少有人知道的生理变化，发生在过渡过程中的反硝化生物膜生长模式。铜绿假单胞菌生物膜对许多抗微生物剂（其是经受来自增殖细胞的主动外排的底物）的抗性表明外排栗可能实质上促成生物膜的先天抗性。在这项研究中，我们研究了与两个多药耐药（MDR）外排泵，MexAB-OprM和MexCD-OprJ，在整个生物膜的发展过程中的基因的表达。使用与gfp的融合，我们能够分析mexA和mexC在发育中的生物膜中的空间和时间表达。值得注意的是，在发育中的生物膜中，mexAB-oprM和mexCD-oprJ的表达没有上调，而是随着时间的推移而降低。北方印迹分析证实这些泵在生物膜中没有过表达。此外，观察到mexAB-oprM和mexCD-oprJ表达的空间差异，最大活性发生在生物膜基底处。使用一系列MDR突变体，我们评估了MexAB-OprM、MexCD-OprJ、MexEF-OprN和MexXY外排泵对铜绿假单胞菌生物膜抗性的贡献。这些分析导致了令人惊讶的发现，即四种表征的外排泵在铜绿假单胞菌生物膜的耐药性表型中不起作用。
Pseudomonas aerginosa biofilms are intrinsically resistant to antimicrobial chemotherapies. At present, very little is known about the physiological changes that occur during the transition from the planktonic to biofilm mode of growth. The resistance of P. aeruginosa biofilms to numerous antimicrobial agents that are substrates subject to active efflux from planktonic cells suggests that efflux pumps may substantially contribute to the innate resistance of biofilms. In this study, we investigated the expression of genes associated with two multidrug resistance (MDR) efflux pumps, MexAB-OprM and MexCD-OprJ, throughout the course of biofilm development. Using fusions to gfp, we were able to analyze spatial and temporal expression of mexA and mexC in the developing biofilm. Remarkably, expression of mexAB-oprM and mexCD-oprJ was not upregulated but rather decreased over time in the developing biofilm. Northern blot analysis confirmed that these pumps were not hyperexpressed in the biofilm. Furthermore, spatial differences in mexAB-oprM and mexCD-oprJ expression were observed, with maximal activity occurring at the biofilm substratum. Using a series of MDR mutants, we assessed the contribution of the MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY efflux pumps to P. aeruginosa biofilm resistance. These analyses led to the surprising discovery that the four characterized efflux pumps do not play a role in the antibiotic-resistant phenotype of P. aeruginosa biofilms.