Dental bacterial DNA are present in the amniotic cavity of healthy pregnant women at term

Aims: To determine if dental bacterial DNA are present in the amniotic cavity of healthy pregnant women undergoing an elective caesarean section at term utilising culture independent techniques. Methods: Pregnant Australian women undergoing an elective caesarean section were recruited. Women completed questionnaires addressing demographics, past and current pregnancies and medical history. One high vaginal swab and three amniotic cavity swabs (amniotic fluid, newborn axilla and placental) were collected under sterile conditions. Samples were analysed using culture-independent techniques to detect the presence of predefined pathogenic bacterial taxa of the oral microbiome. Taxa isolated from the amniotic cavity swabs were compared to those isolated from the vaginal swab. Results: DNA from taxa isolated from the amniotic cavity but not vagina included A. xylosoxidans, A. tumefaciens, B. subtilis, Bartonella sp, Bergeyella sp, C. concisus, C. curvus, C. durum, D. microaerophilus, G. haemolysans, G. morbillorum, G. adiacens, G. elegans, K. pneumoniae, L. casei, L. paracasei, L. fermentum, P. aeruginosa, P. fluorescens, P. pseudoalcaligenes, P. stutzeri, R. microluginosa, S. maltophilia, S. pneumoniae, S. salivarius, S. sanguinis, V. dispar, V. parvula and Xanthomonas sp. Conclusion: The DNA of many pathogenic oral bacteria can be identified in the amniotic cavity of healthy pregnant women at term when utilising culture-independent techniques. Given DNA is not always present in the vagina, the study findings fulfill one criterion necessary for oral haematogenous spread to the amniotic cavity.