Li Zhaoxia, Liu Youning, Wang Rui, Li Aimin
Department of Respiratory Diseases, The Second Artillery General Hospital, Beijing, 100088, People's Republic of China.
World J Microbiol Biotechnol. 2014 Nov;30(11):2927-32. doi: 10.1007/s11274-014-1720-2. Epub 2014 Aug 18.
In comparison with ciprofloxacin, levofloxacin and moxifloxacin, antimicrobial activity of nemonoxacin against ciprofloxacin-susceptible/-resistant methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) was determined with the availability to select resistant mutants evaluated. Minimum inhibitory concentrations and mutant prevention concentrations of quinolones were determined by agar dilution method, that concentrated bacterial cells were spread onto Mueller-Hinton agar plates containing antibacterials at different concentrations. Selection index (SI) was calculated. Minimum inhibitory concentration and mutant prevention concentration of nemonoxacin were 0.063 and 0.25 μg/mL for ciprofloxacin-susceptible MSSA and those were 0.5 and 4.0 μg/mL for ciprofloxacin-resistant MSSA, lower than observations of three fluoroquinolones distinctly. SI of nemonoxacin and moxifloxacin were similar, with narrower mutant selective window than levofloxacin and ciprofloxacin. Minimum inhibitory concentration and mutant prevention concentration of nemonoxacin were 0.25 and 2.0 μg/mL for ciprofloxacin-susceptible MRSA, which were 0.5 and 16.0 μg/mL for ciprofloxacin-resistant MRSA. Values were lower than those determined from fluoroquinolones. Nemonoxacin presents good antimicrobial activity against clinical isolates of S. aureus, especially for ciprofloxacin-resistant strains. But stepwise mutant accumulation of ciprofloxacin-resistant MRSA can be hardly inhibited by nemonoxacin with pharmacokinetic parameters considered.
与环丙沙星、左氧氟沙星和莫西沙星相比，测定了奈诺沙星对环丙沙星敏感/耐药的甲氧西林敏感金黄色葡萄球菌（MSSA）和甲氧西林耐药金黄色葡萄球菌（MRSA）的抗菌活性，并评估了其选择耐药突变体的可能性。采用琼脂稀释法测定喹诺酮类药物的最低抑菌浓度（MIC）和突变预防浓度（MPC），即将浓缩的细菌细胞接种到含有不同浓度抗菌药物的穆勒-欣顿琼脂平板上。计算选择指数（SI）。奈诺沙星对环丙沙星敏感MSSA的MIC和MPC分别为0.063和0.25μg/mL，对环丙沙星耐药MSSA的MIC和MPC分别为0.5和4.0μg/mL，明显低于三种氟喹诺酮类药物的测定值。奈诺沙星和莫西沙星的SI相似，其突变选择窗比左氧氟沙星和环丙沙星更窄。奈诺沙星对环丙沙星敏感MRSA的MIC和MPC分别为0.25和2.0μg/mL，对环丙沙星耐药MRSA的MIC和MPC分别为0.5和16.0μg/mL。这些值低于氟喹诺酮类药物的测定值。奈诺沙星对金黄色葡萄球菌临床分离株具有良好的抗菌活性，尤其是对环丙沙星耐药菌株。但考虑到药代动力学参数，奈诺沙星很难抑制环丙沙星耐药MRSA的逐步突变积累。
