Very basic microbiology questions - (Nov/17/2008 )
Some real n00b questions. I apologize in advance.
If an organism is said to be capable of fermenting inositol, what sort of indicator is required for this? Can I simply whip up a batch of media that uses inositol as the sole carbon source, and if the organism (Klebsiella) grows, is this considered adequate? Or does there need to be a pH indicator to show growth? I'm trying to tell K. pneumoniae from E. coli, you see, and I have what appears to be both growing on MacConkey.
Motility is considered another factor in which Kp can be discriminated from E. coli. Is this simply a matter of adding some material from a colony to some physiological pH solution and putting it on a slide, and looking for motile organisms? Would 400x be adequate for this?
Any suggestions as to how to tell Kp from E. coli on the cheap and easy (I can formulate or purchase a variety of media, but some simply aren't readily available to the individual) would be welcome. TIA!
Well, if you do a methyl red test, E. coli will be positive and K. pneumoniae will be negative. The protocol is pretty basic, so look online. Should be able to get all reagents easy and cheap. Also, Eosin-methylene blue agar: E. coli will be green with a metallic sheen and K. pneumoniae will be purple colonies with no sheen. Also easy to make and get reagents.
Reference: Koneman's Color Atlas and Textbook of Diagnostic Microbiology.
For motility test just use semisolid agar media, stab the center of the tube around halfway to the bottom with your inoculum and incubate 24-48 hrs. Expected results for motility are cloudiness around the stabbing line (away from it, actually). A negative result will have no visible turbidity in the stabbing line.
And by the way, a simple slang question....
What the hell means n00b? (really, I have no clue) 
What the hell means n00b? (really, I have no clue)
Slang for "newbie."
All right- I have accumulated some EMB agar, as well as citrate and urea tubes. I will re-culture my organisms and run what I find on these media- and maybe make some semi-solid stuff, too. But first- some other basic questions.
In microbiology, does "fermenting" mean that they can use that particular carbon source for energy, i.e.: "glucose fermenting" means if the only carbon source is glucose, they can persist in that fashion? If so, does growth alone mean it can ferment that sugar, or is some pH indicator (or other indicator) required to indicate fermentation (as in the case of MacConkey agar)?
Secondly, if I want to run some fermentation tests on Klebsiella pneumoniae, is there a good basal medium that I can use- a decent medium to which I can add inositol, glucose, maltose, xylose, etc. to see if the strain that I culture can grow using *only* a given carbon source? If this is the case, what indicator (as in the paragraph above) do I need to use, if any?