Inconsistent localization of gram-positive bacteria to prostate-specific specimens from patients with chronic prostatitis.

OBJECTIVES: To determine the rate of gram-positive localizations and whether repetitive cultures demonstrate consistent localization of gram-positive bacteria in patients with chronic prostatitis symptoms.
METHODS: We repeated localization cultures at different visits for untreated patients with chronic prostatitis symptoms.
RESULTS: A total of 470 patients with chronic prostatitis had lower urinary tract localization cultures done. Ten-fold increases in the concentrations of gram-positive bacteria were noted when the postprostatic massage (VB3) or expressed prostatic secretions cultures were compared with first-void urine (VB1) cultures from 29 patients (6%). This was comparable to the 7% rate of gram-negative chronic bacterial prostatitis. We studied 49 patients who had undergone 130 repeated localization studies (median 2, range 2 to 4). Repeatedly negative studies were found in 20 patients, including 19 who each had undergone two studies and 1 who had undergone four studies. Of 9 patients who each had undergone three or four studies, 9 demonstrated localization of at least one gram-positive species. Of the 29 patients with gram-positive localizations, 27 (94%) did not have consistent localization of the gram-positive species.
CONCLUSIONS: Patients with chronic prostatitis demonstrated localization of gram-positive bacteria, but the results were seldom reproducible in untreated patients. Gram-positive localizations may represent nonpathogens, transient bacterial colonization of the lower urinary tract, or intermittent shedding of prostatic pathogens. The limitations of traditional cultures highlight the need for better diagnostic approaches and improved recommendations for antimicrobial therapy.