Expert: Florence M Rollwagen - 3/25/2009

Question
I have an enviromental sample of bacteria from dog saliva.  I have checked the Bergey manaual to help classify the genus of my bacteria but have not been able to based on the information they have tables for and the information I have.

The tests:
Blood agar: alpha hemolysis
Motility agar: Motile
Conitions that allow growth: Candle Jar and Anaerobic
TSI Agar: Yellow, positive for sucrose and/or lactose and dextrose fermentation
Starch Plate: positive
MSA agar: Negative, no growth
MRVP: Negative MR, Positive VP acetoin
SIM: Negative
Gram Staining: Positive
Shape: Cocci

What would be the best way to figure out the classification?  I have tried Bergey manual with no success.  I need to be able to classify down to genus with possible species.

Is there another manual or website, that I can use the information that I have?

I am at a complete loss.

Answer
Hi Angela:  Thanks for your interesting question.  To identify environmental bacteria all the way to genus and species is a big job, and I admire your desire to do this.

When I first read your description, I thought it was Staph aureus, a common environmental bacteria also found in saliva.

But when I examined some more, I found a few questions.

When you did your gram stain did you notice if it's a strep or a staph?  If not, a negative stain will give you that information.

Are you sure about motility?  Staph are generally non-motile, but enterococcus (a strep) is motile.  You might try a motility examination (use a young culture).

Alpha or beta hemolysis?

I also searched "canine oral flora" to narrow down the possibilities (to avoid looking for fish bacteria, for example [grin]).
http://findarticles.com/p/articles/mi_m0689/is_n6_v28/ai_7883557


If you can find out the answers to my questions, write back and we'll work some more.

Good luck!

FM Rollwagen, PhD