Occurrence and antimicrobial susceptibility of Ureaplasma parvum (Ureaplasma urealyticum biovar 1) and Ureaplasma urealyticum (Ureaplasma urealyticum biovar 2) from patients with adverse pregnancy outcomes and normal pregnant women.

A recent phylogenetic analysis of Ureaplasma urealyticum resulted in the proposal to divide their 2 biovars into species. We used PCR to compare the distribution of species and the presence of the tet(M) and int-Tn resistance determinants in 63 strains of Ureaplasma spp. isolated from the amniotic fluid of patients with an adverse pregnancy outcome and in 22 strains obtained from the lower genital tract of healthy pregnant women. We also determined the antimicrobial susceptibility of the organisms to erythromycin and tetracycline. U. parvum was the most frequent Ureaplasma species detected in our study. Thus, 50/63 (79.4%) invasive isolates and 17/22 (77.3%) lower genital tract isolates corresponded to U. parvum, whereas 12/63 (19%) invasive isolates and 4/22 (18.2%) non-invasive strains corresponded to U. urealyticum. A mixture of species was found in 2 women. We found no significant differences in the antimicrobial susceptibility of isolates according to species or origin of isolation. Sixty-two strains of Ureaplasma spp. (74.7%) were susceptible to erythromycin, and 21 strains (25.3%) were intermediately susceptible. Sixty-eight isolates (81.9%) were susceptible to tetracycline, 2 strains (2.4%) were intermediate and 13 strains (15.7%) were resistant. DNA sequences related to the tet(M) determinant and the int-Tn gene were found in all tetracycline-resistant isolates.