Do infectious agents cause interstitial cystitis?

The possibility that infectious agents play a role in the etiology of interstitial cystitis (IC) has been investigated for a number of years. Early studies were directed toward attempts to cultivate bacteria and fungi on routine culture media and microscopic examinations of urine or bladder tissue specimens for the presence of microorganisms. In more recent years, this approach has been expanded to include sophisticated culture techniques to search for the presence of fastidious and unusual organisms that would not be detected by routine culture methods. Similarly, the presence of viruses has been sought by incubating specimens from interstitial cystitis patients in mammalian cell cultures to detect cytopathic effects. None of these approaches has provided convincing evidence that micro-organisms or viruses are associated with IC. The latest attempts to search for the presence of bacteria have made use of the polymerase chain reaction (PCR) to amplify bacterial 16S rRNA genes that would be present if bacteria were present in bladder tissue or urine of IC patients. This approach allows bacteria to be detected and even identified without culture. However, the results from the great majority of bladder biopsy samples analyzed by these molecular techniques have been negative. PCR strategies have also been used to search for the presence of certain viruses in IC specimens, again without success. At this time, the results from laboratory culture, light and electron microscopy, and various molecular strategies to detect micro-organisms and viruses in IC specimens all argue against an infectious etiology for IC.