Concept explainers
To analyze:
The presence of Vibrio cholerae in water sample and still tested negative in the multiple tube technique.
Introduction:
Multiple tube technique is used to detect Coliforms in water sample which detect fecal contamination. It is done in three stages, the presumptive test, the confirmation test, and the completion stage.
Explanation of Solution
If the water sample gives negative result for Vibrio cholerae, then it does not means that the sample does not contain this pathogen. V. choleraecan enter inside a viable and nonculturable state and then it will not form colonies on culture plates. In such a state, the cell density of V. choleraebecomes very low in water. So, if a very small amount of water sample is taken then, enough cells of this pathogen may not be present in the sample.
Water with high concentration of Vibrio cholera pathogenic bacterium gives negative test result in Multiple tube technique because of the presence of Vibrio cholerae in its viable and nonculturable state.
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Chapter 52 Solutions
Laboratory Experiments in Microbiology (12th Edition) (What's New in Microbiology)
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