Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigboejlen 4, DK-1870 Frederiksberg C, Denmark.
Present address: Chr. Hansen, Hørsholm, Denmark.
Microbiology (Reading). 2020 Sep;166(9):849-853. doi: 10.1099/mic.0.000953. Epub 2020 Jul 22.
is a major bacterial foodborne-pathogen. Ciprofloxacin is an important antibiotic for the treatment of , albeit high rates of fluoroquinolone resistance have limited its usefulness. Persister-cells are transiently antibiotic-tolerant fractions of bacterial populations and their occurrence has been associated with recalcitrant and persistent bacterial infections. Here, time-kill assays with ciprofloxacin (200×MIC, 25 µg ml) were performed in strains 81-176 and RM1221 and persister-cells were found. The frequency of survivors after 8 h of ciprofloxacin exposure was approx. 10 for both strains, while after 22 h the frequency was between 10-10, depending on the strain and growth-phase. Interestingly, the stationary-phase cultures did not display more persister-cells compared to exponential-phase cultures, in contrast to what has been observed in other bacterial species. Persister-cells after ampicillin exposure (100×MIC, 200 µg ml) were not detected, implying that persister-cell formation in is antibiotic-specific. In attempts to identify the mechanism of ciprofloxacin persister-cell formation, stringent or SOS responses were not found to play major roles. Overall, this study reports ciprofloxacin persister-cells in and challenges the notion of persister-cells as plainly dormant non-growing cells.
是一种主要的食源性细菌病原体。环丙沙星是治疗的重要抗生素，尽管氟喹诺酮类药物的耐药率很高，但已限制了其用途。持留细胞是细菌种群中暂时具有抗生素耐受性的部分，其存在与难治性和持续性细菌感染有关。在这里，用环丙沙星（200×MIC，25μg/ml）对 81-176 和 RM1221 株进行了时间杀伤试验，并发现了持留细胞。两种菌株在环丙沙星暴露 8 小时后，幸存者的频率约为 10，而在 22 小时后，频率在 10-10 之间，具体取决于菌株和生长阶段。有趣的是，与在其他细菌物种中观察到的情况相反，与指数期培养物相比，静止期培养物并没有显示出更多的持留细胞。未检测到氨苄青霉素暴露（100×MIC，200μg/ml）后的持留细胞，这意味着 中环丙沙星持留细胞的形成是特定于抗生素的。在试图确定环丙沙星持留细胞形成的机制时，未发现严格或 SOS 反应起主要作用。总的来说，这项研究报告了 中环丙沙星持留细胞的存在，并挑战了持留细胞仅仅是休眠的非生长细胞的概念。
