New insight into the analysis of amniotic fluid microflora using 16S rRNA gene sequencing
Introduction:
Intra-uterine infection is a major cause of spontaneous pre-term birth before 30 weeks of gestation. In addition, intra-amniotic inflammation is present in approximately 80 % of patients with acute cervical insufficiency. The microbiome is known to cause intra-amniotic infection causing pre-term birth. Recently, surveys of the microbial communities in the vagina or in amniotic fluid using sequencing of the 16s rRNA gene have been carried out. Here, we reported the microbiome compositions in mid-trimester amniotic fluids in two pregnant women with cervical insufficiency identified using 16S rRNA sequencing.
Case presentation:
A 35-year-old primipara and a 37-year-old nullipara were admitted to Hallym University Medical Center, Korea. They were negative for nitrazine and Actim PROM (Medix Biochemica) tests, and their amniotic membranes had prolapsed beyond the external os. A physical examination indicated that cerclage using a uniconcave balloon should be carried out, and amnioreduction was performed. Thereafter, they delivered at very early pre-term birth of below 24 weeks and the birth outcomes were pre-natal death. Analysis of mid-trimester amniotic fluids in these two pregnant women with cervical insufficiency identified Sneathia sanguinegens and Fusobacterium nucleatum. These bacteria were not identified using vaginal or amniotic cultures.
Conclusion:
These results suggest that 16S rRNA gene sequencing can be used to identify the predominant microbiome causing pre-term birth in pregnant women with cervical insufficiency. Further studies are needed in large samples to improve our understanding of microbes causing pre-term birth and to prevent pre-term birth in pregnant women with cervical insufficiency.