Microbial profiling of cpn60 universal target sequences in artificial mixtures of vaginal bacteria sampled by nylon swabs or self-sampling devices under different storage conditions.

ABSTRACT

The vaginal microbiome is increasingly characterized by deep sequencing of universal genes. However, there are relatively few studies of how different specimen collection and sample storage and processing influence these molecular profiles. Here, we evaluate molecular microbial community profiles of samples collected using the HerSwab™ self-sampling device, compared to nylon swabs and under different storage conditions. In order to minimize technical variation, mixtures of 11 common vaginal bacteria in simulated vaginal fluid medium were sampled and DNA extracts prepared for massively parallel sequencing of the cpn60 universal target (UT). Three artificial mixtures imitating commonly observed vaginal microbiome profiles were easily distinguished and proportion of sequence reads correlated with the estimated proportion of the organism added to the artificial mixtures. Our results indicate that cpn60 UT amplicon sequencing quantifies the proportional abundance of member organisms in these artificial communities regardless of swab type or storage conditions, although some significant differences were observed between samples that were stored frozen and thawed prior to DNA extraction, compared to extractions from samples stored at room temperature for up to 7days. Our results indicate that an on-the-market device developed for infectious disease diagnostics may be appropriate for vaginal microbiome profiling, an approach that is increasingly facilitated by rapidly dropping deep sequencing costs.