水中产气荚膜梭菌在不同过滤培养体系中的表型特征的研究

Studies on the phenotypic characteristics of Clostridium perfringens in different filtration systems in water

目的比较水中的产气荚膜梭菌在2种不同孔径滤膜和2种培养基上的计数结果,并探讨其机理。方法用0.22μm和0.45μm 2种不同孔径的滤膜过滤添加产气荚膜梭菌的矿泉水后,将滤膜贴在亚硫酸盐-多粘菌素-磺胺嘧啶琼脂培养基(sulfite-polymyxin-sulfadiazine agar,SPS)和胰胨-亚硫酸盐-环丝氨酸琼脂培养基(tryptose sulfite cycloserine agar,TSC)上,36℃±1℃厌氧培养24 h,观察菌落形态并进行菌落计数。用扫描电镜观察0.22μm和0.45μm2种滤膜表面的开口大小。结果水样经过2种不同孔径的滤膜过滤后,产气荚膜梭菌在TSC和SPS上的计数结果无显著性差异(P>0.05)。但与SPS相比,产气荚膜梭菌在TSC上更易形成特征性黑色菌落;与孔径为0.22μm滤膜相比,在孔径为0.45μm滤膜上生长的菌落更大。电镜扫描发现,0.22μm滤膜和0.45μm滤膜的平均表面开口分别为25μm、40μm,后者的表面开口更大。结论水样通过0.45μm孔径滤膜过滤,贴在TSC琼脂上培养,更适用于矿泉水中产气荚膜梭菌的检验。

Objective To compare the counting results of Clostridium perfringens in water on two kinds of filters with different pore sizes and two kinds of culture media,and to explore the mechanism.Methods The mineral water with Clostridium perfringens was filtered by 0.22μm and 0.45μm filters membranes.The filter membranes were attached to sulfite-polymyxin-sulfadiazine agar(SPS)and tryptose sulfite cycloserine agar(TSC),and anaerobic culture was conducted at 36℃±1℃for 24 h.The bacterial colony morphology was observed and the bacterial colony count was performed.The sizes of the openings on membrane surfaces of 0.22μm and 0.45μm filters were observed by scanning electron microscope.Results After the water samples were filtered by two filters with different pore sizes,there was no significant difference in the count results of Clostridium perfringens on TSC and SPS(P>0.05).However,compared with SPS,Clostridium perfringens is more likely to form characteristic black colonies on TSC.Compared with the filtration membrane with an aperture of 0.22μm,the bacterial colonies growing on the filtration membrane with an aperture of 0.45μm were larger.Scanning electron microscopy found that the average surface opening of the 0.22μm filter and the 0.45μm filter were 2.5μm and 4.0μm respectively,the latter had a larger surface opening.Conclusion The water sample was filtered by 0.45μm pore size filter membrane and cultured on TSC agar,which is more suitable for the test of Clostridium perfringens in mineral water.