A prospective study of microorganisms in urine and bladder biopsies from interstitial cystitis patients and controls

Interstitial cystitis (IC) is a chronic inflammatory condition of the bladder of unknown etiology. We tested the hypothesis that a microorganism would be found at higher prevalence in urine or bladder tissue from women with IC than from control women.

Urine and bladder tissue were obtained at cystoscopy from 11 IC patients and 7 control subjects. These specimens were cultured for a variety of fastidious and nonfastidious bacteria, mycobacteria, fungi, and viruses. In addition, special staining techniques were used to examine biopsy specimens and cytospun urine, and tissue sections and outgrowths of explanted bladder cells were examined by electron microscopy.

Cultures of urine from 6 of 11 IC patients grew five different bacteria (Corynebacterium sp. Klebsiella pneumoniae, Lactobacillus sp, Streptococcus constellatus, and Streptococcus morbillorum), human cytomegalovirus, or Torulopsis glabrata; one of these organisms (Lactobacillus sp) was found in urine from 2 patients. Although contamination by urethral organisms is possible, the prevalence of microorganisms in urine of IC patients (6 of 11) was significantly greater than in urine of control subjects (0 of 7) (P < 0.05). Acridine orange staining revealed rods with appropriate morphology in urine from 4 of the 5 IC patients who had positive bacterial cultures and yeastlike organisms in urine and bladder tissue specimens that grew Torulopsis. Additionally, rodlike organisms were seen in urine from 2 IC patients with negative bacterial cultures and cocci were seen in the urine of 1 control patient. Biopsy specimens from 2 IC patients grew Torulopsis sp or Lactobacillus sp, in agreement with the results of acridine orange staining and culture of urine from these patients; in contrast, specimens from 3 control subjects grew small numbers of Pseudomonas sp or Staphylococcus epidermidis, but no organisms were cultured from urine or seen in acridine orange-stained tissue smears. All other cultures and stains were negative.

These data do not provide evidence that IC is associated with infection or colonization by a single microorganism. However, they do generate the hypothesis that the prevalence of microorganisms, especially bacteria at low concentrations, is greater in the urine of IC patients than of control subjects. If these results are confirmed by other controlled studies, the question of whether the presence of these organisms is a cause or a result of IC should be addressed.