Investigating Candida species and associated bacteria from vaginal swabs and smears of symptomatic and asymptomatic adult women: A cross-sectional study

• A unique cluster of Candida albicans and Nakaseomyces glabrata from Thailand • Surface modifications observed on budding yeast cells • A unique interaction between bacteria and Candida yeast cells is reported • Differences in microbiome composition by age and in symptomatic and asymptomatic women is reported • Highest prevalence of Candida colonization observed in women 18-25 years age group Vaginal Candida infections are common among women affecting between 75-80% of women in their lifetime, with a higher prevalence in women of childbearing age. This study assessed vaginal carriage of Candida sp ecies and associated bacteria in adult women. A total of 101 vaginal swabs and smears from symptomatic and asymptomatic adult women were analyzed for presence of Candida sp . using culture, Gram stain, and Next Generations Sequencing. Morphology of selected Candida sp . was conducted using Scanning Electron Microscopy. Candida colonization was observed in 39.6% (40/101) of the women. Candida albicans was identified in 75.0% (30/40) of the women, while non albicans species; Nakaseomyces glabrata was observed in 7.5% (3/40), P. kudriavzevii 5% (2/40), and C. tropicalis in 2.5% (1/40). Women18-25years presented the highest prevalence of colonization among all age groups 47.5% (19/40). A significant difference in vaginal bacteria composition was observed among age groups, 18-25- and 26-35-years (α 0.05 <0.038*, 95% CI -0.16 – 0.99); 26 -35year Candida positive women and 46-55year group (α 0.05 <0.016*, 95% CI -0.28 – -0.03), and between Candida positive and Candida negative women (α 0.05 <0.016*, 95% CI 0.17 – -0.40). Among the Candida positive women, symptomatic individuals had predominantly Gram positive bacteria species 92.6% (23/25) compared to 46% (19/42) in asymptomatic individuals. Five bacteria species were shared between the symptomatic and asymptomatic samples. Unique budding patterns, surface modifications and phylogenetic clusters are reported. Vaginal Candida colonization including differences in microbiome compositions according to age, disease status, and colonizing Candida species are reported. This study opens areas of study in vaginal Candida colonization, pathogen-pathogen interaction, as well as microbiome analysis in more specific age brackets away from the traditional pre-menopausal and menopausal women.