不同微孔滤膜应用于铜绿假单胞菌检测的质量评价分析

Quality evaluation analysis of different microporous filter membranes applied in the detection of Pseudomonas aeruginosa

目的 对应用于包装饮用水中铜绿假单胞菌检测的微孔滤膜进行质量评价分析。方法 以3株来源和菌落特征均不同的铜绿假单胞菌标准菌株为研究对象,分析比较了亲水性微孔滤膜在5种不同材质、4种不同灭菌方式和4种不同品牌情况下的外观特征、过滤速率、滤膜上铜绿假单胞菌的菌落特征和回收率。结果 同种阳性菌在不同材质滤膜上生长的菌落颜色、大小和形态等特征均有差异。不同材质滤膜对铜绿假单胞菌的综合回收率,由大到小依次为混合纤维素酯膜、聚醚砜膜、尼龙膜、聚四氟乙烯膜和聚碳酸酯滤膜。与辐照灭菌方式相比,干热(160℃,2 h)和直接湿热灭菌(121℃,15 min),会造成滤膜不同程度的变形或变黄;5种滤膜均适宜浸泡在水中进行121℃,15 min灭菌;当不影响滤膜外观特征时,灭菌方式对铜绿假单胞菌菌落特征、回收率等无显著影响。结论 当采用滤膜法检测包装饮用水中的铜绿假单胞菌时,宜采用混合纤维素滤膜,必要时采用浸泡在水中进行121℃,15 min灭菌处理。阳性菌的菌落颜色、大小、形状以及回收率等是对滤膜进行适应性评价的重要考虑因素。

Objective To evaluate the quality of the microporous filter membrane used for the detection of Pseudomonas aeruginosa in packaged drinking water.Methods Three standard strains of Pseudomonas aeruginosa with different sources and colony characteristics were selected as the research objects.The 5 kinds of different materials,4 kinds of different sterilization methods and 4 kinds of different brand sources were compared.The appearance characteristics,filtration rate,colony characteristics and recovery rate of the strains on the filter membranes were analyzed.Results The characteristics of colony color,size and morphology of the strains growing on the filter membranes were different among the different materials.The comprehensive recovery rate of Pseudomonas aeruginosa on the mixed cellulose ester,nylon,polyether sulfone,polytetrafluoroethylene and polycarbonate filter were decreased in succession.Compared with irradiation sterilization methods,dry heat(160℃,2 h) and direct wet heat(121℃,15 min) sterilization could cause different degrees of deformation or yellowing of the filter membrane,5 kinds of different filter membranes were suitable for soaking in water for sterilization at 121℃,15min.When the appearance characteristics of the filter membrane were not affected,the sterilization method had no significant effect on the colony characteristics and recovery rate of Pseudomonas aeruginosa.Conclusion It is advisable to use the mixed cellulose ester filter membrane,soak it in water for sterilization at 121℃,15 minutes.when using the filter membrane to detect Pseudomonas aeruginosa in packaged drinking water.The color,size,shape,and recovery rate of positive bacterial colonies are important considerations for evaluating the adaptability of filter membranes.