Thai Van Chi, Pham Hoang Vy, Nguyen Duc Nhat Minh, Lambert Peter, Nguyen Thi Thu Hoai
1 School of Biotechnology, International University, VNU-HCMC , Ho Chi Minh City, Vietnam.
2 School of Life and Health Sciences, Aston University , Birmingham, UK.
Acta Microbiol Immunol Hung. 2017 Sep 1;64(3):245-253. doi: 10.1556/030.64.2017.012. Epub 2017 May 31.
The modulation of efflux pump functions under fluoroquinolone (FQ) exposure is of great concern as it could result in occurrence of multidrug-resistant (MDR) bacterial strains. In this study, MDR mechanism in Pseudomonas aeruginosa induced via moxifloxacin (MOX) pressure was investigated. After serial MOX [concentration of 0.5 × the minimum inhibitory concentration (MIC)] exposure, the fully susceptible P. aeruginosa ATCC 9027 strain has increased its MIC not only toward MOX (1→128 mg/L) but also to other antibiotics. Furthermore, this MOX-exposed strain did not revert to antibiotic-sensitive phenotype when being cultured in antibiotic-free medium for 12 days. No mutation was observed for FQ-target (gyrA and parC) or most investigated efflux regulatory genes (mexT, mexR, and nalC) except nfxB in which a 100-bp deletion was found. This associated with the elevated expression of multidrug efflux pump operon (mexCD-oprJ) which could directly result in MDR phenotype.
氟喹诺酮（FQ）暴露下外排泵功能的调节备受关注，因为这可能导致多重耐药（MDR）菌株的出现。在本研究中，对通过莫西沙星（MOX）压力诱导的铜绿假单胞菌中的MDR机制进行了研究。经过连续MOX [浓度为0.5×最低抑菌浓度（MIC）]暴露后，完全敏感的铜绿假单胞菌ATCC 9027菌株不仅对MOX的MIC增加（从1→128 mg/L），而且对其他抗生素的MIC也增加。此外，该MOX暴露菌株在无抗生素培养基中培养12天时未恢复为抗生素敏感表型。除发现有100 bp缺失的nfxB外，未观察到FQ靶点（gyrA和parC）或大多数研究的外排调节基因（mexT、mexR和nalC）发生突变。这与多药外排泵操纵子（mexCD-oprJ）的表达升高有关，这可能直接导致MDR表型。
