Significance of Ureaplasma urealyticum and Clostridium difficile in Nongonococcal Urethritis

This study was aimed to investigate the pathogenicity of Ureaplasma urealyticum and Clostridium difficile in nongonococcal urethritis (NGU) through isolations of these organisms from men with NGU and without urethritis, and therapeutic study as concerns ureaplasmas. The in vitro antimicrobial susceptibility test of ureaplasmas was also done. U. urealyticum was isolated in significance more frequently from men with NGU than from healthy men, but not significantly than from men with gonococcal urethritis (GU). In quantitative study 105 or more color-changing unit (CCU) per ml of ureaplasmas appeared more frequently in men with NGU (24%) than in healthy men (6%). There was the tendency that number of U. urealyticum in specimens would increase with the progressively more number of polymorphonuclear cells in urethral smear. The antimicrobial susceptibility of 58 clinical isolates of U. urealyticum to 10 antimicrobial agents was measured by microtiter-plate method. Although minocycline (MINO) and doxycycline (DOXY) were the most active against ureaplasmas among an -timicrobial agents tested, 5 strains were not inhibited by 12.5μg per ml of both drugs after 3-day culture for final minimal inhibitory concentration (MIC). These strains were inhibited at concentrations of 6.25μg or less per ml of erythromycin after 3-day culture. The entity for an etiological agent of Ureaplasma in NGU was suggested by the selective therapy using MINO and DOXY being active against Ureaplasma and Chlamydia both, and ampicillin, cephalexin and sulfamethizole being not active against Ureaplasma. U. urealyticum seems to be a characteristically opportunistic pathogen, though it is transmitted sexually. There was no evidence to suggest that C. difficile was associated with NGU or urethral syndrome; that is, from none of 44 men including 19 with NGU and none of 18 women with urethral syndrome C. difficile was not isolated.