BERKELEY, CA (UroToday Inc.) - Chlamydia trachomatis is the most common sexually transmitted disease agent worldwide and is known to be one of the etiological microorganisms of chronic prostatitis. Doxycycline and azithromycin are the most widely prescribed drugs in the treatment of C. trachomatis infections and are often recommended for primary treatment, with the flouroquinolones recommended as alternative drugs. Antibacterial susceptibility against chlamydial organisms isolated from patients has proven variable however. Little is known, for example, about chlamydial survival in the presence of flouroquinolones in patients being treated for bacterial prostatitis.

To clarify this point, activity of four flouroquinolones, as well as azithromycin and doxycycline were investigated and compared in vitro against C. trachomatis isolated from urethral and prostatic fluid culture of patients with chronic prostatitis syndrome (CPS). The study was performed by V. Smelov and colleagues from St. Petersburg, Russia, and published in the November, 2004 issue of European Urology.

A population of 304 men aged 19 to 54 (mean 28 years) with lower urinary tract symptoms (LUTS) compatible with the diagnosis of CPS associated with a positive urethral and prostatic fluid culture of C. trachomatis comprised the study group. The absence of other organisms such as Trichmonas vaginalis, gonococci and genital mycoplasma was confirmed by urethral swab and EPS (expressed prostatic secretion) culture. The in vitro activity against chlamydia was tested for the four flouroquinolones: ofloxacin, ciprofloxacin, pefloxacin and lomefloxacin as well as for doxycycline and azithromycin.

Results showed that the most active agent was azithromycin, followed by ofloxacin, pefloxacin, lomefloxacin and ciprofloxacin. The least active agent among the antibiotics tested was doxycycline. The authors postulate that the widespread use of doxycycline may have contributed to a high level of resistance to this antibiotic within this patient population.

In conclusion, the authors report on the activity of multiple antibiotic agents against Chlamydia trachomatis isolates from men with chronic prostatitis syndrome. The results suggest that azithromycin and ofloxacin show the best in vitro activity against this organism. The authors also suggest that ofloxacin may be the treatment of choice for patients being treated for bacterial prostatitis and chronic prostatitis syndrome because of its activity against other common bacterial isolates as well as against the less common chlamydial agent.

Eur Urol. 2004 Nov; 46(5):647-50