Subject: What influences do pathogenic enteric bacteria have on normal behavior?

I am curious if pathogenic enterics can alter normal behavior. 
Furthermore, if they can, is it a neurological pathway or a metabolic 
by-product that is inducing the changes. I know that bacteria 
proliferate in response to catecholamines, which is a neurological 
link. On the other hand, bacteria produce products which enter the 
system and influence the other flora. This question stems from the 
fact that at any given time the outbred population of humans is 
affected by a subclinical asymptomatic infection. I believe our 
behavior is influenced by nontypical gut flora. 

Re: What influences do pathogenic enteric bacteria have on normal behavior?