Effects of macrolides on the β-lactamase produced in the biofilm of bacteria / 中国医师进修杂志

ABSTRACT

Objective To investigate the effect of azithromycin,erythromycin and roxithromyein at varying concentration on the β-lactamase produced in the biofilm of Klebsiella pneumoniae.Methods Models of Klebsiella 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 groupsbiofilm (group A),by 1 MIC azithromycin (group B1),by 1/8 MIC azithromycin (group B2),by 1 MIC erythromycin (group C1),by 1/8 MIC erythromycin (group C2),by 1 MIC roxithromycin (group D1),and biofilm induced by 1/8 MIC roxithromycin (group D2),with 200 μ1 each.The β-lactamase activity in each group was quantitated.Results The β-lactamase activity in group A,group B1,group B2,group C1,group C2,group D1 and group D2 was 0.6534,0.3196,0.4260,0.5028,0.5108,0.6524 and 0.6470 U/mg respectively.The β-lactamase activity in group B1,group B2,group C1 and group C2 was lower than that in group A,and statistically significant difference was observed (P＜0.05).The B-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.