Characterization of Amniotic Fluid Ureaplasma Species from Pregnancies Complicated by Preterm Prelabor Rupture of Membranes.

Abstract

The main aim of this study was to determine expanded sequence types (eSTs) of Ureaplasma species (U. spp.). DNA isolated from the amniotic fluid of pregnancies complicated by preterm prelabor rupture of membranes (PPROM) using an expanded multilocus sequence typing scheme. Additionally, the study sought to examine whether phylogenetic subgroups of U. spp. DNA differ with respect to maternal demographic and clinical parameters and selected aspects of short-term neonatal morbidity. This retrospective cohort study was focused on singleton pregnancies complicated by PPROM occurring between the gestational ages of 24+0 and 36+6 weeks, where amniocentesis was conducted to assess the intra-amniotic environment and the presence of U. spp. DNA in the amniotic fluid samples was confirmed. The stored aliquots of U. spp. DNA were used to assess differences in nucleotide sequences in six U. spp. genes (ftsH, rpL22, valS, thrS,ureG, and mba-np1) using the eMLST scheme. The expanded multilocus sequence typing scheme was performed in 73 samples of U. spp. DNA isolated from pregnancies complicated by PPROM. In total, 33 different U. spp. DNA eSTs were revealed, 21 (#20, 233-244, 248-251, 253, 255, 259, and 262) of which were novel. The most frequently identified eST was #41, identified in 18% (13/73) of the aliquots. Based on their genetic relationships, the U. spp. DNA was divided into two clusters and four subgroups [cluster I (U. parvum): A, 43% (n = 31); B, 15% (n = 11); and C, 26% (n = 19); cluster II (U. urealyticum): 1; 16% (n = 12)]. Cluster II had a higher rate of polymicrobial findings than cluster I (58% vs 16%; p = 0.005), while subgroup A had the highest rate of concomitant Mycoplasma hominis in the amniotic fluid samples (66%; p = 0.04). In conclusion, Ureaplasma spp. DNA obtained from PPROM consisted of 33 different eSTs of U. spp. DNA. No differences in maternal and neonatal characteristics were found among the phylogenetical subgroups of U. spp. DNA, except for a higher rate of polymicrobial amniotic fluid findings in those with U. urealyticumand the concomitant presence of M. hominis in the amniotic fluid in those with the presence of U. parvum.