Thanks, I actually searched initially for metronidazole and lyme disease through pubmed (which is the Google of medical literature) and passed over one interesting article that could support its use (fortunately not behind a paywall):

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132871/

However, this study was done on petri dish cultures of borellia and didn't actually look at whether or not it improved symptoms in people (which I imagine is a difficult thing to study in this field).

When I searched for borrellia and metronidazole there was one more article for in vitro use from the 1990s: http://www.ncbi.nlm.nih.gov/pubmed/10379684