进口注射用克拉霉素与国产注射用乳糖酸红霉素体内外抗菌活性的比较

Comparing the antibacterial activities between Clarithromycin and Erythromycin in vitro and in vivo

目的研究进口注射用克拉霉素与国产注射用乳糖酸红霉素对四川地区临床分离致病菌的体内、外抗菌活性。方法测定260株临床分离致病菌的最低抑菌浓度(MIC)、最低杀菌浓度(MBC),采用活菌计数法绘制杀菌曲线,并观察细菌接种量、培养基pH和血清蛋白含量对体外抗菌活性的影响,采用小鼠100%mLD菌量测定并计算ED50及95%可信限来观察注射用克拉霉素的体内抗菌活性。结果进口注射用克拉霉素MBC的浓度较其MIC的浓度高4～16倍,为抑菌剂;当接种菌量由5×103CFU·mL-1增至5×107CFU·mL-1时,进口注射用克拉霉素的MIC值增加2～4倍。pH偏碱,抗菌作用增强,尤以pH8～9时,抗菌作用明显增强,血清浓度75%时,抗菌作用有所减弱。进口注射用克拉霉素静脉给药,对敏感的金黄色葡萄球菌、化脓性链球菌和流感嗜血杆菌感染的小鼠具有保护作用,优于国产注射用乳糖酸红霉素。结论进口注射用克拉霉素比国产注射用乳糖酸红霉素具有更好的抗菌活性,可供临床参考。

OBJECTIVE To study the antibacterial activities of Clarithromycin for injection against clinically isolated pathogenic bacteria from Siehuan area in vitro and in vivo. METHODS Minimal inhibitory concentrations （MIC） and minimal bactericidal concentrations （MBC） were determined on 260 clinically isolated pathogenic bacteria. Killing curve was drawn by determination of colony forming unit counts at each time interval. The influences of the inoculum size, pH and concentration of serum protein on antibacterial activities were observed. The antibacterial activities of Clarithromyein for injection were observed by using 100% mLD bacteria and calculating ED50 and 95% confidence limit. RESULTS MBC concentration of imported Clarithromycin for injection was 4 - 16 times than its MIC concentration and can be use as baeteriostat. When the inoeulum size increased from 5 ×10^3CFU·mL^-1 to 5 ×10^7CFU·mL^-1 , the MIC value of Clarithromycin for injection was increased 2 - 4 times. In alkali environment （ pH8 - 9） the antibiotic action can be strengthened. Concentration of serum protein in 75% weakened the antibiotic action. Imported Clarithromyein for i. v. injection have protective action to the mice which infected by staphylococcus aureus, streptococcus and haemophilus influenzae. Compare with the imported Clarithromycin for injection they had the same activities, but much better than erythromycin lactobionate for injection. CONCLUSION Imported Clarithromyein for injection much better in vitro and in vivo antibacterial activity than Erythromyein.