亚甲蓝对体外不同细菌培养结果的影响

Impacts of methylene blue on culture results of different bacteria in vitro

[目的]探讨分析染色剂亚甲蓝(methylene blue,MB),一种通常用作关节假体周围感染的示踪剂阳离子染料,对体外不同细菌培养结果的影响。[方法]体外制备8种标准菌株,包括金黄色葡萄球菌(staphylococcus aureus,SAU)、表皮葡萄球菌(staphylococcus epidermidis,SEP)、人葡萄球菌(staphylococcus hominis,SHO)、大肠杆菌(escherichia coli,ECO)、肺炎克雷伯菌(klebsiella pneumoniae,KPN)、鲍曼不动杆菌(acinetobacter baumannii,ABA)、化脓链球菌(streptococcus pyogenes,SPY)和白色念珠菌(candida albicans,CAL)的菌悬液来模拟关节液细菌培养。所有标准菌株的菌悬液均稀释50倍,并分为三组(每组5份),分别添加0.1%MB、0.05%MB和0.45%无菌盐水。接种于琼脂平板培养基培养24 h,比较三组的菌落计数。[结果]SHO和ABA菌落计数由低至高依次为0.1%MB组<0.05%MB组<盐水组,差异有统计学意义(P<0.05)。而SEP、ECO、KPN、SPY和CAL的菌落计数三组间差异均无统计学意义(P>0.05)。Spearman相关分析表明,MB浓度与SHO和ABA菌落计数呈显著负相关(P<0.05),而与SAU、SEP、ECO、KPN、SPY、CAL的菌落计数无相关性(P>0.05)。[结论]MB对SHO和ABA有剂量依赖性抑菌作用,但对其他6个菌株无作用。

[Objective]To explore the impacts of methylene blue(MB),a cationic dyes usually used as tracer agent for periprosthetic joint infection,on the culture results of different bacteria in vitro.[Methods]Eight standard bacterial strains were prepared in vitro,includ⁃ing staphylococcus aureus(SAU),staphylococcus epidermidis(SEP),staphylococcus hominis(SHO),escherichia coli(ECO),klebsiella pneumoniae(KPN),bacterial suspensions of acinetobacter baumannii(ABA),streptococcus pyogenes(SPY)and candida albicans(CAL),for simulation of bacterial culture of synovial fluid.The bacterial suspensions of all the standard bacterial strains were diluted 50 times and divided into three groups with 5 samples in each group,and then treated with 0.1%MB and 0.05%MB and 0.45%sterile saline,respective⁃ly.The colony count was compared among the 3 groups.[Results]The colony counts of SHO and ABA strains were ranked from low to high in sequence of 0.1%MB group<0.05%MB group<saline group,with a statistically significant difference(P<0.05).However,there were no significant differences in colony counts in terms of SEP,ECO,KPN,SPY and CAL among the 3 groups(P>0.05).As results of Spear⁃man correlation analysis,the MB concentration was significantly negatively correlated with SHO and ABA colony counts(P<0.05),whereas which had no correlation with colony counts of SAU,SEP,ECO,KPN,SPY and CAL(P>0.05).[Conclusion]The MB has dose-dependent inhibitory effect on SHO and ABA,but has no effect on the other 6 bacterial strains.