staph/strep

Phil jorge2 at earthlink.net
Fri Jun 26 21:41:21 EST 1998


ying wrote:
> 
> i want to isolate staph and strep.
>                           Sample
>                                 |
>                        Gram stain
>                                 |
>           Colombia nutrient agar
>                                 |
>                          Catalase
>                       |                     |
>                     +                   ( -)
> Mannitol salt agar
>                     |                       |
>                     Heat tolerance
>                    Biochemical test
> Question
> 1.    Will this method worked?
> 2.    If catalase test is (-), can I confirm the sample contain strep?
> 3.    Are there any possible contamination from other gram positive cocci?
> 4.    Any other suggestion or comments?
> 5.    Is it necessary to plate the sample on mannitol salt agar (if catalase
> test is positive) to select staph?
> 6.    Can I substitute Colombia with any seletive media for both staph and
> strep?

The scheme seems confused.  I'd 1st ensure a pure culture (use Columbia
blood agar) and note hemolysis.  Then Gram stain, catalase, coagulase
and some of the API-type systems.
There are other catalse (-) bugs though your sample source may not offer
them.



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