大环内酯类抗生素对生物被膜菌产β-内酰胺酶的作用

Effects of macrolides on the β-actamase produced in the biofilm of bacteria

目的探讨不同浓度阿奇霉素、红霉素、罗红霉素对生物被膜肺炎克雷伯杆菌产β-内酰胺酶的影响。方法应用改进的平板培养法建立肺炎克雷伯杆菌生物被膜模型，用扫描电镜观察鉴定。取肺炎克雷伯杆菌30株，经37℃24h孵育，比浊法配制0．5麦氏比浊标准（MCF）菌悬液，分为A组（生物被膜组）、B，组[1最低抑菌浓度（MIc）阿奇霉素生物被膜组]、B2组（1／8MIC阿奇霉素生物被膜组）、C1组（1MIC红霉素生物被膜组）、C2组（1／8MIC红霉素生物被膜组）、D1组（1MIC罗红霉素生物被膜组）、D2组（1／8MIC罗红霉素生物被膜组）七组，每组200斗l。分别检测各组产β-内酰胺酶的活性。结果A组、B1组、B2组、C1组、C2组、D1组、D2组β-内酰胺酶的活性分别为0．6534、0．3196、0．4260、0．5028、0．5108、0．6524、0．6470U／mg，B1组、B2组、C1组、C2组B．内酰胺酶活性均明显低于A组，差异有统计学意义（P〈0．05）；D。组、D：组13．内酰胺酶活性与A组比较差异无统计学意义（P〉0．05）。B。组B．内酰胺酶活性明显低于B：组，差异有统计学意义（P〈0．05）；C1组与C2组比较差异无统计学意义（P〉0．05）。结论高浓度的阿奇霉素对生物被膜有较强的破坏作用。

Objective To investigate the effect of azithromycin,erythromycin and roxithromycin at varying concentration on the β-laetamase produced in the biofilm of Klebsiella pneumoniae. Methods Models of KlebsieUa pneumoniae were built up with the modified flat-board method and identified with the confocal scanning laser microscopy, Thirty Klebsiella pneumoniae were incubated at 37 ℃ for 24 h,and allocated into 7 groups： biofilm （group A）, by 1 MIC azithromycin （group Bl）,by 1/8 MIC azithromycin （group B2）,by 1 MIC erythromyein （group C1）,by 1/8 MIC erythromycin （group C2）,by 1 MIC roxithromycin （group Dl）,and biofilm induced by 1/8 MIC roxithromycin （group D2）,with 200 ILl each. The β-lactamase activity in each group was quantitated. Results The β-lactamase activity in group A, group B1,group B2,group Cl,group C2,group Dl and group D2 was 0.6534, 0.3196, 0.4260, 0.5028, 0.5108,0.6524 and 0.6470 U/rag respectively. The β -lactamase activity in group B,, group B2, group Cz and group C2 was lower than that in group A, and statistically significant difference was observed （P 〈 0.05 ）. The 15 -lactamase activity in group D1 and group D2 was similar to that in group A, and no statistically significant differences was observed between them （P 〉 0.05）. The β-lactamase activity in group B1 was lower than that in group B2,and statistically significant difference was observed （P 〈0.05）. No statistically significant difference was observed between group C1 and group C2 （P 〉 0.05）. Conclusion Azithromycin at higher concentration exerts better effects on biofilm formation than other macrolides.