150. IN VITRO CHARACTERISATION OF BIOFILM FORMATION IN HUMAN FOLLICULAR FLUID

Abstract

Previous studies have detected bacteria in follicular fluid collected at the time of trans-vaginal oocyte retrieval but this was not shown to adversely affect ART outcomes. The antimicrobial properties of follicular fluid have also been investigated, and follicular fluid was reported to be inhibitory to Gram positive bacteria after four days, but supported the growth of Gram negative bacteria. In this study 36 follicular fluid specimens collected from assisted reproductive technology (ART) patients were tested for the presence of bacteria by culture and 16S rRNA PCR assays. Follicular fluid aliquots (24) were incubated and subcultured for 28 weeks and the ability of these follicular fluids to form biofilms in vitro was assessed. A further 12 follicular fluid specimens were inoculated into broth media with and without the addition of estradiol and progesterone at concentrations reported in follicular fluid of hyperstimulated women. Bacteria in polymicrobial (22%) or singles species populations (78%) were detected in the 24 follicular fluid specimens tested. The most prevalent bacteria detected were Lactobacillus species (18/35 total bacterial isolates, 51%) and Propionibacterium spp. (5/35, 14%). All follicular fluids supported the growth of bacteria in vitro for up to 28 weeks. Bacteria in 18/24 (75%) of follicular fluid specimens, formed biofilms in vitro. The majority of biofilms formed were grade IV 7/18 (39%) or grade III biofilms 7/18 (39%). Lactobacilli were also the most prevalent cultivable species within mature biofilms (51% of total isolates). Whilst high levels of steroid hormones were required for the growth of Bifidobacterium spp. in vitro, the growth of both Streptococcus agalactiae and Escherichia coli was inhibited by these hormones. Follicular fluid is not sterile and is an excellent growth media for bacteria, capable of supporting survival for long periods of time. Bacteria which can survive within follicular fluid over time can form mature biofilms, which enables persistence. Women undergoing ART cycles have elevated concentrations of steroid hormones within their follicular fluid and this can modulate the ability of some bacterial species to proliferate. The impact of these bacteria on the developing oocyte and ART pregnancy outcomes requires further investigation.