Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Poursina street, Enghelab-e-Eslami avenue, PO Box: 14155-6446, Tehran, Iran.
Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Sci Rep. 2021 May 5;11(1):9582. doi: 10.1038/s41598-021-88977-z.
Stenotrophomonas maltophilia exhibits wide spectrum of fluoroquinolone resistance using different mechanisms as multidrug efflux pumps and Smqnr alleles. Here, the role of smeDEF, smeVWX efflux genes and contribution of Smqnr alleles in the development of fluoroquinolone resistance was assessed. Ciprofloxacin, levofloxacin and moxifloxacin resistance were found in 10.9%, 3.5%, and 1.6% of isolates, respectively. More than four-fold differences in ciprofloxacin MICs were detected in the presence of reserpine and smeD, F, V expression was significantly associated with ciprofloxacin resistance (p = 0.017 for smeD, 0.003 for smeF, and 0.001 for smeV). Smqnr gene was found in 52% of the ciprofloxacin-resistant isolates and Smqnr8 was the most common allele detected. Fluoroquinolone resistance in S. maltophilia clinical isolates was significantly associated with active efflux pumps. There was no correlation between the Smqnr alleles and ciprofloxacin resistance; however, contribution of the Smqnr genes in low-level levofloxacin resistance was revealed.
嗜麦芽窄食单胞菌通过多种机制表现出广谱氟喹诺酮耐药性，包括多药外排泵和 Smqnr 等位基因。本研究评估了 smeDEF、smeVWX 外排基因以及 Smqnr 等位基因在氟喹诺酮耐药发展中的作用。结果显示，10.9%、3.5%和 1.6%的分离株分别对环丙沙星、左氧氟沙星和莫西沙星耐药。在利血平和 smeD、F、V 表达的存在下，检测到环丙沙星 MIC 值的差异超过四倍，并且 smeD（p=0.017）、smeF（p=0.003）和 smeV（p=0.001）的表达与环丙沙星耐药显著相关。在 52%的环丙沙星耐药分离株中发现了 Smqnr 基因，Smqnr8 是检测到的最常见等位基因。嗜麦芽窄食单胞菌临床分离株的氟喹诺酮耐药与主动外排泵显著相关。虽然 Smqnr 等位基因与环丙沙星耐药之间没有相关性，但揭示了 Smqnr 基因在左氧氟沙星低水平耐药中的作用。
