Baranova N N, Neyfakh A A
Department of Medicinal Chemistry and Pharmacognosy and Center for Pharmaceutical Biotechnology, University of Illinois, Chicago 60607, USA.
Antimicrob Agents Chemother. 1997 Jun;41(6):1396-8. doi: 10.1128/AAC.41.6.1396.
A Streptococcus pneumoniae strain selected for resistance to ethidium bromide demonstrated enhanced energy-dependent efflux of this toxic dye. Both the ethidium resistance and the ethidium efflux could be inhibited by the plant alkaloid reserpine. The ethidium-selected cells demonstrated cross-resistance to the fluoroquinolones norfloxacin and ciprofloxacin; this resistance could also be completely reversed by reserpine. Furthermore, reserpine potentiated the susceptibility of wild-type S. pneumoniae to fluoroquinolones and ethidium. The most plausible explanation for these results is that S. pneumoniae, like some other gram-positive bacteria, expresses a reserpine-sensitive multidrug transporter, which may play an important role in both intrinsic and acquired resistances of this pathogen to fluoroquinolone therapy.
一株对溴化乙锭具有抗性的肺炎链球菌表现出对这种有毒染料增强的能量依赖性外排。溴化乙锭抗性和溴化乙锭外排均可被植物生物碱利血平抑制。经溴化乙锭筛选的细胞对氟喹诺酮类药物诺氟沙星和环丙沙星表现出交叉抗性；这种抗性也可被利血平完全逆转。此外，利血平增强了野生型肺炎链球菌对氟喹诺酮类药物和溴化乙锭的敏感性。对这些结果最合理的解释是，肺炎链球菌与其他一些革兰氏阳性细菌一样，表达一种对利血平敏感的多药转运蛋白，这可能在该病原体对氟喹诺酮治疗的固有抗性和获得性抗性中都发挥重要作用。
