Prevalence of participants with oral yeasts.

Overgrowth of Candida yeasts in the oral cavity may result in the development of oral thrush in immunocompromised individuals. This study analyzed the diversity and richness of the oral mycobiota of patients clinically diagnosed with oral thrush (OT), follow-up of oral thrush patients after antifungal therapy (AT), and healthy controls (HC). Oral rinse and oral swab samples were collected from 38 OT patients, 21 AT patients, and 41 healthy individuals (HC). Pellet from the oral rinse and oral swab were used for the isolation of oral Candida yeasts on Brilliance Candida Agar followed by molecular speciation. ITS1 amplicon sequencing using Illumina MiSeq was performed on DNA extracted from the oral rinse pellet of 16 OT, 7 AT, and 7 HC oral rinse samples. Trimmed sequence data were taxonomically grouped and analyzed using the CLC Microbial Genomics Module workflow. Candida yeasts were isolated at significantly higher rates from oral rinse and swab samples of OT (68.4%, p Candida albicans specifically, was noted in OT (60.5%, p albicans Candida species was dominant in HC. Analysis of oral mycobiota from OT patients showed the presence of 8 phyla, 222 genera, and 309 fungal species. Low alpha diversity (Shannon index, p = 0.006; Chao-1 biased corrected index, p = 0.01), varied beta diversity (Bray-Curtis, p = 0.01986; Jaccard, p = 0.02766; Weighted UniFrac, p = 0.00528), and increased relative abundance of C. albicans (p = 3.18E-02) was significantly associated with the oral mycobiota of OT vs. HC. This study supported that C. albicans is the main etiological agent in oral thrush and highlights the association of fungal biodiversity with the pathophysiology of oral thrush.</div

Prevalence and relative abundance of significant oral fungal species in AT vs. OT groups (arranged from most to least significant relative abundance).

Prevalence and relative abundance of significant oral fungal species in AT vs. OT groups (arranged from most to least significant relative abundance).</p

Demographical information of OT, HC and AT participants for ITS1 amplicon analysis.

Demographical information of OT, HC and AT participants for ITS1 amplicon analysis.</p

Significant underabundance of the top 25 strains in OT vs. HC oral rinse samples.

Significant underabundance of the top 25 strains in OT vs. HC oral rinse samples.</p

Relative abundance of oral fungi at species level (top 10 most abundant in each study group; arranged from highest to lowest species relative abundance in OT patients).

Relative abundance of oral fungi at species level (top 10 most abundant in each study group; arranged from highest to lowest species relative abundance in OT patients).</p

Significant differential abundance (p < 0.05) of fungal taxa within group pairs.

a) OT vs. HC (Top 25 strains that showed significant downregulation in OT patients), b) AT vs. HC (A total of 20 strains showed significant upregulation in AT patients, while 1 species showed significant downregulation), c) AT vs. OT (Top 25 strains that showed significant upregulation in AT patients, while only 2 strains showed significant downregulation).</p

Chao-1 bias-corrected and Shannon alpha diversity index raw values.

Chao-1 bias-corrected and Shannon alpha diversity index raw values.</p

Bray-Curtis, Jaccard, Euclidean, Unweighted UniFrac, Weighted UniFrac beta diversity raw values for OT, HC and AT groups.

Bray-Curtis, Jaccard, Euclidean, Unweighted UniFrac, Weighted UniFrac beta diversity raw values for OT, HC and AT groups.</p

Prevalence and relative abundance of significant oral fungal species in OT vs. HC groups (arranged from most to least significant relative abundance).

Prevalence and relative abundance of significant oral fungal species in OT vs. HC groups (arranged from most to least significant relative abundance).</p

Box plots depicting alpha diversity measures for each study group (AT, HC, and OT).

(a) Shannon entropy and (b) Chao-1 biased corrected analysis. The different colors represent the oral thrush status of participants.</p