左旋氧氟沙星的药效学研究

Pharmacokinetical Studies of Levofloxacin

测定了左旋氧氟沙星对家禽致病菌的抗菌活性和抗菌后效应(PAE),观察了其对人工感染鸡葡萄球菌病的治疗效果。结果表明:左旋氧氟沙星有广谱抗菌作用,对家禽常见致病菌(革兰氏阳性、阴性菌)均有高度的抗菌活性。对鸡大肠杆菌O74等标准菌株的MIC介于0.05-0.20μg/ml之间,而对临床分离菌株的MIC介于0.20-0.80μg/ml之间。左旋氧氟沙星等氟喹诺酮类抗菌药物对革兰氏阳性、阴性菌均产生明显的PAE,并呈浓度依赖性。左旋氧氟沙星对人工感染鸡葡萄球菌病有良好的治疗效果,其分别按每升水25 mg、50 mg、100mg及氧氟沙星按每升水50 mg混饮4 d,治愈率分别为81.3％、90.6％、93.8％、68.8％,感染对照组的死亡率为59.4％。

The in vitro minimum inhibitory concentration (MIC) and postantibiotic effects(PAEs) of levofloxacin and other several fluoroquinolones against some avian pathogens and their efficacy in the control of experimentally induced staphylococcosis in chickens were investigated. The results revealed that levofloxacin possessed an excellently potent activity against a wide microbial spectrum including both gram-negative and gram-positive bacteria. MICs of levofloxacinIn against standard strains were 0. 05-0. 20 μg/ml , and its MICs against clinical isolates were 0. 20-0. 80 μg/ml. Its activity against standard strains was slightly weaker or similar to that of enrofloxacin and ciprofloxacin, but stronger a-gainst clinical isolates. The PAEs induced by levofloxacin and other several fluoroquinolones were determined by means of viable counting procedure after the removal of the antimicrobials. The results demonstrated that PAEs of these drugs against gram-negative and gram-positive bacteria were long, and showed concentration dependent. The treatment experiment suggested that levofloxacin was effective in controlling avian staphylococcosis attributable to S. aureus when administered in drinking water. Following treatment with three doses levofloxacin (high dose 100 mg/L, middle dose 50 mg/L,low dose 25 mg/L), ofloxacin (50 mg/L) via the drinking water for 4 successive days, the cure rate of above drugs against avian staphylococcosis were 81. 3% 、90. 6%、93. 8% 、68. 8% respectively. The mortality of infected and untreated chickens was 59. 4%.