Cervico-vaginal carriage rate of Escherichia coli in pregnant women receiving antinatal control in a public hospital of Buenos Aires

ADRIANA PEREYRA; SACERDOTI FLAVIA; SCALISE MARÍA LUJÁN; CASALE ROBERTO; IBARRA CRISTINA; LEONINO PATRICIA; FERREIROS JOSÉ A

Buenos Aires

Congreso; Meeting of the International Federation of Placenta Associations (IFPA2019) and Latin American Symposium on Maternal-Fetal Interaction and Placenta (VIII SLIMP).; 2019

International Federation of Placenta Associations

Presence of Escherichia coli in the vaginal microbiome has been associated to pregnancy and neonatal complications. We have previously reported that Shiga toxin (Stx) producing E. coli (STEC) infections during pregnancy may cause maternal or fetal damage mediated by Stx2 in rats. To our knowledge, it has not been reported the presence or colonization of STEC in vagina of pregnant women. We propose that the presence of STEC in human vagina may be a risk factor for pregnancy and neonatal complications. Our objective was to investigate the presence of E. coli in cervico-vaginal cultures from pregnant women and to identify virulence factors related to STEC infection. Methods: Cervico-vaginal swabs from 103 pregnant women with gestational age of 14 to 30 weeks from the National Hospital A. Posadas were enrolled. Samples were enriched in Tryptic Soy Broth and sub-cultivated on sorbitol-MacConkey (SMAC) agar for 24 h in order to detect no sorbitol fermenting colonies, characteristic of STEC. Genomic DNA was purified from colonies and the presence of the uidA gene exclusive for E. coli was analyzed by PCR. Positive colonies for uidA were additionally checked for O157, eae and Stx2 genes currently associated with STEC virulence factors. Results: Of the 103 cervico-vaginal samples analyzed 16 showed colonies in SMAC agar but none sample had sorbitol fermenting negative colonies. PCR studies showed that 15 samples carried out the uidA gene (14.5%, 15/103). In addition, 9 of them (60%, 9/15) expressed stx2 gene. All of them were negative for O157 and eae genes. Conclusions: Our study confirmed the prevalence of E coli in cervico-vaginal fluid of pregnant women in Argentina. Furthermore, we detected for the first time the stx2 gene in several E. coli samples. These results suggest that STEC strains may colonize the vagina. Further studies are needed in order to elucidate if the presence STEC in vagina may be a risk for pregnancy complications.