Introduction Glycogen is both an energy source and metabolic product of lactobacilli. Our objective was to assess the association between free glycogen in the cervicovaginal lavage (CVL) and vaginal microbiota as assessed by Nugent score, quantitative polymerase chain reaction (qPCR) for Lactobacillus crispatus and L.iners, and quantitative culture detection of lactobacilli.

Methods Healthy women (n = 55) aged 18–45 without clinical bacterial vaginosis, gonorrhoea, chlamydia or trichomoniasis were enrolled. A 10 mL CVL sample was collected and tested for glycogen using a fluorometric assay (BioVision) and protein was assessed using the Lowry assay. A vaginal smear was interpreted using the Nugent criteria. Separate vaginal swabs were used for vaginal culture and qPCR. Differences in median levels of glycogen were evaluated using the Kruskal-Wallis test.

Results Glycogen concentrations (ng/ug protein) were significantly higher in women having a Nugent score of 0–3,  compared to those having scores of 4–6, or 7–10 (457 vs 398 vs 128, P = 0.049). Glycogen content was higher among women colonised by L crispatus vs other lactobacilli (L. jensenii, L. gasseri, L. iners) vs no lactobacilli (426 vs 280 vs 36, p = 0.013) based on culture. Similarly, the 38 women having L. crispatus dominant ( >10⁵) flora by qPCR had higher glycogen levels vs the 15 women who had dominant L iners (413 vs 201, P = 0.036).

Conclusion Increased levels of free glycogen in the CVL are associated with flora dominated by L. crispatus. It is unknown whether glycogen enhances L. crispatus colonisation, or whether L. crispatus synthesises glycogen, increasing the glycogen content.

Disclosure of interest statement Nothing to declare.