I came across this interesting article the other day. It looks at the differences in the gut microbiome between healthy controls and women with IC, using stool samples. It found that there are reduced levels of some gut bacteria in women with IC and that they also had elevated levels of glyceraldehyde compared to the controls.
So given that other studies have also found differences in the urinary microbiome in people with IC, for me, there really does seem to be some sort of link to an infection.
Could an overgrowth of some species of bacteria cause ICBPS? Could a deficiency in some species cause it?
Here is the article if you are interested in reading it.
http://www.nature.com/articles/srep26083
Braundmeier-Fleming, A. et al. Stool-based biomarkers of interstitial cystitis/bladder pain syndrome.Sci. Rep. 6, 26083; doi: 10.1038/srep26083 (2016)
and the one about the urinary microbiome -
http://bmcmicrobiol.biomedcentral.com/articles/10.1186/1471-2180-12-205
Siddiqui, H., Lagesen, K., Nederbragt, A. J., Jeansson, S. L., & Jakobsen, K. S. (2012). Alterations of microbiota in urine from women with interstitial cystitis. BMC Microbiology, 12(1), 1-11. doi: 10.1186/1471-2180-12-205