Candida species and oral mycobiota of patients clinically diagnosed with oral thrush

Abstract

Overgrowth ofCandidayeasts 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 oralCandidayeasts 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.Candidayeasts were isolated at significantly higher rates from oral rinse and swab samples of OT (68.4%, p < 0.001) and AT (61.9%, p = 0.012) patients, as compared to HC (26.8%). Predominance ofCandida albicansspecifically, was noted in OT (60.5%, p < 0.001) and AT (42.9%, p = 0.006) vs. HC (9.8%), while non-albicans Candidaspecies 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 ofC.albicans(p = 3.18E-02) was significantly associated with the oral mycobiota of OT vs. HC. This study supported thatC.albicansis the main etiological agent in oral thrush and highlights the association of fungal biodiversity with the pathophysiology of oral thrush.