【摘要】 目的探讨壳聚糖季铵盐对肺炎克雷伯菌的体外抑菌作用。方法以梯度稀释涂布平板法检测壳聚糖和壳聚糖季铵盐对肺炎克雷伯菌的直接抑菌作用;采用Real-Time PCR技术检测肺炎克雷伯菌生物膜形成相关的重要基因lsrR、lsrK和gmd的表达;并以结晶紫染色法检测肺炎克雷伯菌的生物膜形成情况。结果干预后6 h时点开始,壳聚糖和壳聚糖季铵盐孔的存活菌计数均显著降低(P<0.05);干预后12 h壳聚糖季铵盐孔的存活菌计数显著低于壳聚糖组,壳聚糖季铵盐和壳聚糖对待检肺炎克雷伯菌的12 h抑菌率分别为(72.6±8.0)%和(50.2±9.3)%(P<0.05)。壳聚糖和壳聚糖季铵盐均能上调lsrR基因表达;壳聚糖季铵盐使lsrK基因表达下调,gmd基因表达也有下调趋势。从干预后6 h开始,壳聚糖和壳聚糖季铵盐对肺炎克雷伯菌的生物膜形成都有显著抑制作用,与对照组比较差异均有统计学意义(P<0.05);但壳聚糖组与壳聚糖季铵盐组之间比较差异并无统计学意义(P>0.05)。结论壳聚糖和壳聚糖季铵盐能够有效抑制肺炎克雷伯菌增殖及生物膜形成。壳聚糖季铵盐的抑菌能力强于壳聚糖,同时可影响肺炎克雷伯菌生物膜形成相关的多个基因的表达。更多还原

【Abstract】 Objective To investigate the in vitro inhibitory effect of quaternized chitosan against Klebsiella pneumoniae.Methods Plating serial dilutions were used to detect the direct inhibitory effects of chitosan and quaternized chitosan against Klebsiella pneumoniae.Real-time PCR was employed to detect the expression of important biofilm formation related genes lsrR,lsrK and gmd.Crystal violet staining was utilized to examine the biofilm formation of Klebsiella pneumoniae.Results There were significant decrease in the live bacteria counts in chitosan and quaternized chitosan wells from 6 h after treatment(P<0.05),and the live bacteria counts in quaternized chitosan wells were significantly lower than those in chitosan wells at 12 h after treatment,with the 12-h inhibitory ratios of chitosan and quaternized chitosan of(50.2±9.3)% and(72.6±8.0)% respectively(P<0.05).Chitosan and quaternized chitosan increased the expression of lsrR gene,quaternized chitosan decreased the expression of lsrK gene,and there was also a downward trend of expression of gmd gene after treatment with quaternized chitosan.Chitosan and quaternized chitosan achieved an inhibition on the biofilm formation of Klebsiella pneumoniae from 6 h after treatment(P<0.05),while there was no significant difference in the biofilm formation inhibition ability between chitosan and quaternized chitosan(P>0.05).Conclusion Chitosan and quaternized chitosan can effectively inhibit the proliferation and biofilm formation of Klebsiella pneumoniae.The antibacterial activity against Klebsiella pneumoniae from quaternized chitosan is better than that of chitosan,and the expression of multiple biofilm formation related genes is influenced by quaternized chitosan.更多还原