Expert: Walter Hintz - 3/31/2007

Question
QUESTION: My son is doing a science fair project on the bacterial content of the human, cat, dog, and snake mouth. There is alot of information relating to the TYPES of bacteria found in all of the above, except the mouth of a snake (specifically a nonpoisonous ball python)We are looking for web sites that would list the types of bacteria commonly found in a snakes mouth (besides the obvious samonella found in all reptiles)Based on the research we have currently acquired,humans/cats & dogs all have "potty mouths",and it's a matter of the types of bacteria that differ in each (cats have Pasteurella, dogs and humans don't) We would appreciate any help that you could give us to answer this question. [We read your reply to Kirk's question and found it very helpful in how to phrase the hypothesis as to which species has more bacteria rather than who's mouth is cleaner] Thankyou, Kim
ANSWER: Hi Kim
It appears that you have done a lot of checking regarding the bacterial content in mouths.  Is this a project using a scientific method or a research project.  Using scientific your son must design an experiment to test things out.  All mouths contain bacteria because the inside of the mouth is still out side the body. Pasteurella is a common bacterial genus and most do not cause any disease.
 As to snakes I have no idea what type of bacteria you would find there but logic tells me that the mouth would contain any bacteria in the snakes environment and any that would be on the prey the snake eats.

---------- FOLLOW-UP ----------

QUESTION: He will be using a scientic method of swabbing the mouths of each species. He will be using sheep agar to grow the bacteria and the petri dishes will be incubated at 37 degrees C, and disposed of in biohazard(thanks to the lab in the hospital where I work as an RN)There will be 3 trials for each species and he's hoping not only to determine which species has the most growth, but also the types of bacteria that grow.
The snake used in this is the family pet and his/her diet(never had it sexed) consists exclusively of feeder rats purchased from the local pet store. So i gues the question would now become what types of bacteria would a rat carry since that is the snakes food source.

Answer
I am glad to see there is a nurse supervising as  I worry when young people grow bacteria on plates.
I do not know the requirements for this project but I think he is introducing too many variables here with all these different mouths.  What is his actual hypothesis? Does he have resources for the qualitative part of the study. He will probably have to Gram Stain  The quantitative part is easy but identifying bacteria is not.I know. I spent time as a diagnostic bacteriologist for the US Army and the VA
As for the rat the only concern is what the rat is carrying on the fur.