Staph strain on MSA - (Oct/26/2010 )
Does this make any sense?
I have a Staph strain, im testing it against different disinfectants...anyway after exposure to a disinfectant i subculture on MSA. I examined my results and found that some colonies grew WITH MANNITOL FERMENTATION (ie the agar turned yellow) and others grew WITH NO MANNITOL FERMENTATION (agar stayed pink).
Can the same strain sometimes be a fermentor and sometimes not??? Anybody have any idea! 
maryjo on Tue Oct 26 17:24:27 2010 said:
Does this make any sense?
I have a Staph strain, im testing it against different disinfectants...anyway after exposure to a disinfectant i subculture on MSA. I examined my results and found that some colonies grew WITH MANNITOL FERMENTATION (ie the agar turned yellow) and others grew WITH NO MANNITOL FERMENTATION (agar stayed pink).
Can the same strain sometimes be a fermentor and sometimes not??? Anybody have any idea!
Hola Maryjo, Iīm not a microbiology expert, and I donīt know the metabolism of Staph.But I think that before treatments your strain metabolizes mannitol, and the treatment has produce in some of the bacteria mutations with made them unable to fermetate mannitol. Do you think that this is a reasonable explanation?. Good luck
How sure are you that you have only one strain in your bacterial cultures?
Well with respect to if im sure its only one strain, im pretty sure bcz it was identified using an automated identification system. If no other logical explanation exists then, i would have to question the purity of this strain.
Protodler, your hypothesis makes alot of sense! I am gonna go through some literature to see if such a phenemonon is documented (my fingers are crossed 
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If anyone knows of a reference that confirms any of these plz share it 