Furuhata Katsunori, Kato Yuko, Goto Keiichi, Saitou Keiko, Sugiyama Jun-Ichi, Hara Motonobu, Fukuyama Masahumi
School of Environmental Health, Azabu University, 1-17-71, Fuchinobe, Sagamihara, Kanagawa 229-8501, Japan.
Biocontrol Sci. 2007 Jun;12(2):39-46. doi: 10.4265/bio.12.39.
Twenty-five yellow chromogenic strains isolated from hospital tap water samples collected nationwide were identified by partial 16S rDNA sequencing. In addition, the chlorine resistance of the isolates was experimentally investigated. The results showed that of the strains tested, 12 strains (48.0%) were Sphingomonas ursincola/natatoria, which was most frequently identified, followed by 2 strains (8.0%) of Mycobacterium frederiksbergense and 1 strain (4.0%) each of Sphingomonas adhaesiva, Sphingopyxis witflariensis and Porphyrobacter donghaensis. The other strains were not identified clearly but they belonged to the order of Alphaproteobacteria. On the other hand, the identification results by sequencing and biochemical property testing were not consistent in any of the strains, showing that it was difficult to accurately identify the yellow chromogenic bacteria in tap water based on only their biochemical properties. When the 25 isolates were exposed to 0.1 mg/l residual free chlorine for 1 minute, 22 isolates (88.0%) survived. When the CT (Concentration Time) value killing 99.99% of the bacteria was investigated in 6 of these survivors, M. frederiksbergense (Y-1 strain) was most resistant to chlorine with the CT value of 32 mg x min/l, followed by S. ursincola/natatoria (Y-7 strain) with the CT value of 3.3 mg x min/l. The CT values of Y-5 (Sphingomonas sp.), Y-27 (S. ursincola/natatoria) and Y-21 (Asticacaulis sp.) were within the range of 0.9-0.1 mg x min /l. Of the 6 strains, S. adhaesiva (Y-10) showed the weakest resistance with the CT value of 0.03 mg x min/l. It was clarified that most yellow chromogenic bacteria isolated from hospital tap water were Sphingomonas spp., and these bacteria were experimentally resistant to chlorine.
通过部分16S rDNA测序对从全国范围内收集的医院自来水样本中分离出的25株黄色产色菌株进行了鉴定。此外，还对分离株的耐氯性进行了实验研究。结果显示，在所测试的菌株中，12株（48.0%）为乌氏鞘氨醇单胞菌/游泳鞘氨醇单胞菌，这是最常鉴定出的菌株，其次是2株（8.0%）弗雷德里克斯堡分枝杆菌，以及各1株（4.0%）的黏附鞘氨醇单胞菌、维氏鞘氨醇单胞菌和东海卟啉杆菌。其他菌株未明确鉴定，但它们属于α-变形菌纲。另一方面，测序和生化特性测试的鉴定结果在任何菌株中都不一致，这表明仅根据生化特性很难准确鉴定自来水中的黄色产色细菌。当将这25株分离株暴露于0.1 mg/l的余氯中1分钟时，22株（88.0%）存活。当对其中6株存活菌进行杀灭99.99%细菌的CT（浓度×时间）值研究时，弗雷德里克斯堡分枝杆菌（Y-1株）对氯的耐受性最强，CT值为32 mg·min/l，其次是乌氏鞘氨醇单胞菌/游泳鞘氨醇单胞菌（Y-7株），CT值为3.3 mg·min/l。Y-5（鞘氨醇单胞菌属）、Y-27（乌氏鞘氨醇单胞菌/游泳鞘氨醇单胞菌）和Y-21（束丝藻属）的CT值在0.9 - 0.1 mg·min/l范围内。在这6株菌中，黏附鞘氨醇单胞菌（Y-10）的耐受性最弱，CT值为0.03 mg·min/l。已明确从医院自来水中分离出的大多数黄色产色细菌为鞘氨醇单胞菌属，并且这些细菌经实验证明具有耐氯性。
