Antimicrobial Susceptibility of Genital Ureaplasma spp. and Mycoplasma hominis

Background/Objectives: Ureaplasma spp. and Mycoplasma hominis may be detected as colonizers or in association with urogenital disease, while antimicrobial resistance and methodological variability complicate interpretation of susceptibility data. This study aimed to characterize local in vitro phenotypic antimicrobial susceptibility patterns of Ureaplasma spp. and M. hominis and to explore organism- and sex-associated differences. Methods: In this retrospective microbiological surveillance study, 242 patients were tested between April 2023 and April 2025 using the Mycoplasma IES commercial culture-based system. Specimens with insufficient growth or mixed Ureaplasma spp./M. hominis growth were excluded, leaving 176 single-organism-positive patients with valid susceptibility results. Eleven antimicrobial agents were evaluated using the assay-defined categorical interpretation. Results: Ureaplasma spp. were detected in 145 patients (82.4%) and M. hominis in 31 (17.6%). Phenotypic resistance was highest for clindamycin (99.4%), ciprofloxacin (91.5%), and ofloxacin (64.2%), whereas susceptibility was high for josamycin (99.4%), minocycline (98.9%), pristinamycin (98.9%), and tetracycline (84.1%). M. hominis showed substantially greater resistance than Ureaplasma spp. to clarithromycin, erythromycin, roxithromycin, and levofloxacin (all p < 0.001). Unadjusted sex differences in macrolide resistance were considered exploratory because M. hominis occurred almost exclusively among women. Conclusions: The findings provide local assay-derived phenotypic surveillance data and demonstrate marked organism- and antimicrobial-specific variation. Because the commercial assay does not distinguish U. urealyticum from U. parvum and reference MIC confirmation was not performed, the results should be interpreted within these methodological limitations and should not be used alone to infer clinical treatment efficacy.