【目的】为合理应用阿莫西林治疗猪金黄色葡萄球菌感染。【方法】采用了体内药动和体外药效联合的方法研究了阿莫西林在血清和组织笼液中抗金黄色葡萄球菌的活性。【结果】体外测定,阿莫西林在血清和组织笼液中对猪金黄色葡萄球菌的MIC均在0.2 μg·mL^-1<MIC<0.4 μg·mL^-1的范围之内。如果在血清和组织液中添加更多的细菌,则需要高于MIC药物浓度才能能持续抑制细菌的生长。猪按10 mg·kg^-1的剂量肌内注射阿莫西林后,在血清中,半效浓度(EC50)为143.63±54.35,即血清药物浓度为2.39 μg·mL^-1时可产生50%最大效应。在组织液中,半效浓度(EC50)为29.61±5.07,即组织液药物浓度为0.49 μg·mL^-1时可产生50%最大效应。【结论】临床上选择阿莫西林治疗猪金黄色葡萄球菌感染时,用药的剂量和间隔应根据实际情况确定,当治疗猪金黄色葡萄球菌轻度感染时,建议给药方案可设定为10 mg·kg^-1体重的剂量进行颈部肌内注射,给药间隔为2次/日。当治疗重度感染时由于体内MIC的升高,体内药物维持抗菌时间减少,必须增加给药次数,可设为3次/日,必要时可增加为4次/日。
[Objective] The research was performed for the rational usage of amoxicillin in treating pigs infected by staphylococcus aureus. [Method] The combined method of pharmacokinetics in vivo and pharmacodynamics in vitro was used to survey and evaluate the pharmacokinetics-pharmacodynamics relationship of amoxicillin against staphylococcus aureus. [ Result] The MICs of amoxicillin against Staphylococcus aureus in serum or tissue cage fluid were 0.2 μg·mL^-1〈MIC〈0.4 μg·mL^-1 in vitro. The concentration of amoxicillin that is more than MIC in serum or tissue fluid will be needed to inhibit the bacteria if lots of staphylococcus aureus was added. EC50 were 143.63±54.35 and 29.61±5.07 respectively in serum and tissue fluid of pigs after intramuscular administration at 10 mg·kg^-1 body weight. Amoxicillin produced 50% of the maximal antibacterial effect when the concentration of amoxicillin was 2.39 μg·mL^-1 and 0.49 μg·mL^-1, respectively, in serum and tissue fluid. [Conclusion] Dosage regime should be designed according to specific case when amoxicillin was employed to treat pigs infected by staphylococcus aureus I.M injections should be administered in the amount of 20mg daily per kilo of body weight, subdivided into injections every 12 hours when pigs are infected by low-grade infection of staphylococcus aureus. When the infection become more serious, dosage regime of 30-40mg daily per kilo body weight should be designed and subdivided into injections every 6-8 hours.