Mycoplasma hominis and interstitial cystitis.

Antibodies to Mycoplasma hominis were detected by indirect hemagglutination in nine (56%) of 16 patients with chronic interstitial cystitis. In seven patients (44%), titers of greater than or equal to 160 were found. Antibodies to Ureaplasma urealyticum were detected in three (19%) of these patients; in only one patient was a high titer, i.e., greater than or equal to 160, found. M. hominis was isolated from voided urine of two patients, and U. urealyticum was recovered from the urine of three patients. A similar incidence of antibodies to M. hominis was found in 20 age- and sex-matched women treated transurethrally for bladder tumors. The high incidence of indirect hemagglutination antibodies to M. hominis found in these two groups of urologic patients who were subjected to repeated instrumentation of the urinary tract remains unexplained.