P-1162. Colonization Rates and Antimicrobial Susceptibility of <i>Mycoplasma hominis</i> and <i>Ureaplasma urealyticum</i> in Adolescent Girls: Comparison with Young Adults

Abstract Background Sexually transmitted infection rates are increasing among adolescents and young adults and remain a serious health problem worldwide. Mycoplasma hominis and Ureaplasma species are sexually transmitted and considered etiologic agents causing various urogenital diseases. This study aimed to estimate the prevalence and antimicrobial susceptibility of M. hominis and U. urealyticum in adolescent girls and to compare them with young women. Methods We evaluated the results of M. hominis and U. urealyticum isolated from vaginal swab culture between January 2011 and August 2023. The data were selected from young women aged 12-26 and analyzed by dividing the two groups into adolescents (12-18 years) and young adults (19-26 years). Results Among 66 adolescent girls, 58 (87.9%) were positive for mycoplasma culture. Twenty-nine (43.9%) had both M. hominis and U. urealyticum. Compared with the young adult group, colonization rates of M. hominis (45.5% [30/66] vs. 21.7% [64/295], P=0.0002) and U. urealyticum (86.4% [57/66] vs. 79.4% [219/295], P=0.0373) were significantly higher in the adolescent group. As age increased, colonization rates of M. hominis (rho = -0.6703; 95% confidence interval [CI], -0.8840 to -0.2248) and U. urealyticum (rho = -0.5993; 95% CI, -0.8550 to -0.1091) tended to decrease. Macrolides (azithromycin, clarithromycin, and erythromycin) susceptibility rate of M. hominis was less than 10% in both groups. Of M. hominis isolates from adolescents, susceptibility rates to azithromycin, clarithromycin, and erythromycin were 0.0%, 6.7%, and 0.0%, respectively. Ninety percent and 76.7% of M. hominis isolates from adolescents were susceptible to doxycycline and tetracycline. Compared with the young adult group, the macrolides susceptibility rate of U. urealyticum was significantly lower in the adolescent group: azithromycin (36.8% vs. 53.4%, P=0.0368), clarithromycin (47.4% vs. 68.9%, P=0.0031), and erythromycin (38.6% vs. 54.3%, P=0.038). Susceptibility rates of U. urealyticum to doxycycline and tetracycline were 94.7% and 87.7% in the adolescent group. Conclusion Compared with young adults, higher rates of colonization and resistance to macrolides for both M. hominis and U. urealyticum were more frequently observed in adolescent girls. Disclosures All Authors: No reported disclosures