Bathing water and E.Coli. Help!

Gordon West GordonWest at
Wed Aug 21 08:58:40 EST 1996

In article <drice.47.321888BB at>, Doug Rice
<drice at> writes

>As long as your broths and agars are sterile, you are probably isolating the 
>organisms you are looking for.  It is a good idea to run negative controls to 
>assure your media sterility.
>I would recommend that you transfer positive LST tubes to tubes of EC broth 
>(again with an inverted durham).  The EC broth is more selective and will 
>eliminate the coliforms and allow the fecal coliforms to thrive.  Streaking 
>positive EC tubes to EMB is still the best method.  If you have a green sheen 
>colony on EMB you can pick it into a tube of LST containing MUG 
>(4-methyl-B-D-glucuronate).  Within four hours E. coli will have broken the 
>MUG molecule into a flourescent compound that glows blue under UV light (black 
>flourescent light will work).
>E. coli can be fairly common in bathing waters.  Lakes, ponds, and streams 
>will also contain variable numbers of this bug due to geese, ducks, pets and 
>livestock.  To help define the source of fecal contamination a fecal 
>streptococci count should also be completed.  Human tend to have a lower 
>percentage of strep than do most other mammals.
>Good luck
>Douglas A. Rice
>CSU-Environmental Quality Laboratory Director
>Applied microbiology of food, air, water and soil.
>drice at
>voice:  (970) 491-6503
>"Moderation is for Monks, take big bites out of life."

Many thanks for your comments. Perhaps I should explain. I am retired
and run a science group for fellow "Wrinklies". Not many people are
interested in science but lots are interested in the environment. We can
also keep the local authorities on their toes. If anyone knows of other
environment related tests I will be pleased to hear of them.
Gordon West
Isle of Wight, UK

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