Rychert R C, Stephenson G R
Appl Environ Microbiol. 1981 May;41(5):1276-8. doi: 10.1128/aem.41.5.1276-1278.1981.
In the examination of stream waters for fecal coliforms, pale yellow colonies regularly appeared on m-FC broth base medium plates. The yellow colonies may comprise 70% more of the colonies of an m-FC plate. More than 80% of these colonies were identified as Escherichia coli by the API 20E identification system and by serotyping. The atypical yellow E. coli strains were not environmentally stressed E. coli since the atypical colonies continued to be yellow on m-FC medium after growth in a nonselective medium. However, 50% of the atypical E. coli strains were o-nitrophenyl-beta-D-galactopyranoside positive, and 20% produced gas in EC medium at 44.5 degrees C. Failure to consider these atypical E. coli strain in water quality analyses could lead to a significant error in the estimation of water quality in some instances.
在对溪流水进行粪大肠菌群检测时，在m-FC肉汤基础培养基平板上经常出现淡黄色菌落。这些黄色菌落可能占m-FC平板上菌落总数的70%以上。通过API 20E鉴定系统和血清分型，超过80%的这些菌落被鉴定为大肠杆菌。这些非典型黄色大肠杆菌菌株并非处于环境压力下的大肠杆菌，因为这些非典型菌落在非选择性培养基中生长后，在m-FC培养基上仍保持黄色。然而，50%的非典型大肠杆菌菌株对邻硝基苯-β-D-半乳糖苷呈阳性反应，20%的菌株在44.5℃的EC培养基中产生气体。在水质分析中若未考虑这些非典型大肠杆菌菌株，在某些情况下可能会导致水质评估出现重大误差。
