[Microbiology] Re: Camp test form primary culture

JEDilworth bactitech at nospamhortonsbay.com
Sun Aug 20 15:52:25 EST 2006

Hippurate is the way to go. We used to use this years ago. I know you can 
buy the Hippurate test commercially.






Hippurate is much better for identification of Group B strep than the CAMP 
test (see first reference). Strep grouping is the best of all, however. If 
you're dealing with identification of pregnant women carrying the organism, 
the grouping is the best way to go. Our lab is using molecular screening now 
for pregant women, which is more sensitive than culture. It depends on what 
you're using the test for. The hippurate test we're using currently requires 
a two hour incubation of a heavy suspension of the organism in a 35 degree 
heat block. Then you add the ninhydrin reagent and incubate another 30 
minutes, checking at 10 minute intervals. It will usually go positive in the 
first ten minutes.

Group B is also resistant to a commercially available "A" disc (bacitracin) 
and sensitive to the antibiotic trimethoprim sulfa (SXT). These discs are 
also available commercially. We used to just streak them onto blood agar and 
drop the two discs, incubate overnight. No zone around "A" and zone around 
SXT = Group B. The organism had to be beta hemolytic on blood to begin with. 
Sometimes, however, we would get a small zone around the A and we would have 
to resort to serogrouping.

These methods are all used upon subculture of the suspect colony, not on 
primary plates.

Judy Dilworth, M.T. (ASCP)

"vincent setiawan" <vincedemagna at yahoo.com> wrote in message 
news:mailman.683.1156100381.20007.microbio at net.bio.net...
> Hai,
>  does anyone know how to make crude Staphylococcal beta toxin, for 
> identification of Streptococcus agalactiae from primery culture, is there 
> any other effective method for identification for Streptococcus agalactiae 
> beside Camp test and Lancefield's serrogrouping test

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