[Microbiology] Re: methylene blue milk

JEDilworth bactitech at nospamhortonsbay.com
Sat Aug 12 23:06:34 EST 2006

Group D enterococci are identified in clinical micro labs by either a PYR 
disc, or a combination of bile esculin agar with a 6.5% NaCl broth. I have 
worked in micro for nearly 30 years and have never used or heard of 
methylene blue milk.  What type of laboratory (research? clinical?) are you 
working in? I'm not saying that it doesn't work, it's just that I never 
heard of it.

Group D enterococci are PYR +, BE+, 6.5% NaCl +

Group D nonenterococci are PYR -, BE+, 6.5% NaCl-

PYR can be bought commercially in disc form. You smear some of the colony on 
it, wait two minutes, add reagent. If positive, it turns pink. Bile esculin 
agar turns black if positive. Negative is no change from the yellowish agar 
slant. The 6.5% NaCl broth is either cloudy from growth or clear from no 
growth. You can also buy this broth with an indicator. It turns from 
purplish blue to yellow if positive for growth.

PYR takes 2 minutes; the other two take overnight incubation.

Judy Dilworth, M.T. (ASCP)

"vincent setiawan" <vincedemagna at yahoo.com> wrote in message 
news:mailman.567.1155407777.20007.microbio at net.bio.net...
> hai
> i just want to know what's the formula for making methylene blue milk for 
> detecting Streptococcus Group D and how to determine positive and negative 
> reaction
> thanks

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