Koide Kentaro, Kongsoi Siriporn, Ouchi Yuki, Yamaguchi Tomoyuki, Nakajima Chie, Suzuki Yasuhiko
1 Division of Bioresources, Hokkaido University Research Center for Zoonosis Control , Sapporo, Japan .
2 Department of Veterinary Public Health, Faculty of Veterinary Medicine, Kasetsart University , Nakhon Pathom, Thailand .
Microb Drug Resist. 2019 Jan/Feb;25(1):14-22. doi: 10.1089/mdr.2018.0078. Epub 2018 Jul 23.
Quinolones show excellent antibacterial activity against Salmonella isolates. Recently, however, quinolone resistance has been increasing in bacteria. This study aimed to examine in vitro, and compare the activity of DC-159a against Salmonella enterica serovar Typhimurium with that of ciprofloxacin and nalidixic acid. Inhibitory effects of quinolones were assessed by the drug concentration needed to inhibit the supercoiling activity of recombinant DNA gyrases by 50% (IC). Dilution methods were used to determine the minimum inhibitory concentration (MIC) of quinolones against two different strains, Salmonella Typhimurium and Salmonella Enteritidis. The ICs of DC-159a against mutant DNA gyrases were much lower than those of nalidixic acid and ciprofloxacin. In particular, the IC of DC-159a against DNA gyrase with double mutation was less than 1/50 that of ciprofloxacin and nalidixic acid. MICs of DC-159a were higher than those of ciprofloxacin but lower than those of nalidixic acid. However, the estimated MICs of DC-159a against Salmonella strains with mutant DNA gyrase were lower than those of ciprofloxacin and nalidixic acid. Therefore, DC-159a can be suggested as an antibiotic candidate for treating salmonellosis caused by quinolone-resistant S. Typhimurium.
喹诺酮类药物对沙门氏菌分离株显示出优异的抗菌活性。然而，近来细菌中的喹诺酮耐药性一直在增加。本研究旨在进行体外检测，并比较DC - 159a与环丙沙星和萘啶酸对肠炎沙门氏菌鼠伤寒血清型的活性。通过抑制重组DNA促旋酶超螺旋活性50%所需的药物浓度（IC）来评估喹诺酮类药物的抑制作用。采用稀释法测定喹诺酮类药物对两种不同菌株——鼠伤寒沙门氏菌和肠炎沙门氏菌的最低抑菌浓度（MIC）。DC - 159a对突变型DNA促旋酶的IC远低于萘啶酸和环丙沙星。特别是，DC - 159a对具有双突变的DNA促旋酶的IC不到环丙沙星和萘啶酸的1/50。DC - 159a的MIC高于环丙沙星但低于萘啶酸。然而，DC - 159a对具有突变型DNA促旋酶的沙门氏菌菌株的估计MIC低于环丙沙星和萘啶酸。因此，DC - 159a可被推荐为治疗由耐喹诺酮的鼠伤寒沙门氏菌引起的沙门氏菌病的抗生素候选药物。
