At what degree can bacteria in other non-gut regions influence our psychiatric well being?

This question is really a spin off this question - http://answers.yahoo.com/question/index?qid=201312...

I realize the direct effect of a brain-gut axis, that's nice and all but I feel that maybe we might be ignoring the full effects of bacteria because the obvious influence directly linked by the ENS and immune system.

With all this hype and excitement about the NIH The Human Microbiome project and all the success of things like feces transplants curing not solely things like clostridium difficile infections, IBS, Chrons disease, and even full blown psychiatric illnesses (1), Is it possible that there could be unknown immune modulation functions that have not yet been discovered that effects the brain with infectious agents on other locations of the body such as the skin?

Take a look at the carpenter ants (2), from a biological stand point I don't see how can we be any different with some unknown pathogens modulating our behaviors. I realize that a lot of the proof and thought is that the modulation is taking place at the vegas nerve which is direct communication with the CNS and therefore it's logical to deduce that for psychiatric illnesses being relieved from some mechanism with some form gut bacteria, immune system, and nervous system interaction, but what about skin bacteria?

Can there be a possibility for mental illness from other locations too, not the psychological aspects of having a rash or something but more directly involved in neurotransmission?

I recently came across a interesting blog post listing case studies from a MD who is using a more than normal aggressive approach for treatment against OCD (3). It's interesting to note that the APA guidelines for treatment of OCD here doesn't outlines these tests. the interesting thing about his post is that he cites other bacteria than typical strep, and secondly he references other locations of the body for the strain to be present influencing the autoimmune response .

A Pubmed search isn't turning up much except some studies showing glutamate/GABA modulation in OCD and if recall correctly some bacteria in the gut produce neuromodulating chemicals on glutamate pathways. I found it interesting that a majority of serotonin is found in the stomach and for some reason OCD also hypothesized to be influenced on serotonin modulation. That is as far as I got in that area.

So what do you think about infectious agents on the skin influencing our brain with antibodies or some other indirect immune function?

What am I getting wrong here? This is a serious question too.

1) http://www.ncbi.nlm.nih.gov/pubmed/23759244 - Note it's kind of new concept - 2013 research

2) http://en.wikipedia.org/wiki/Ophiocordyceps_unilat... - carpenter ants

3) http://beverlyhillsshrink.blogspot.com/2012/03/adu...

Thanks guys