Molecular Analysis of Fungal Populations in Patients with Oral Candidiasis Using Internal Transcribed Spacer Region

Abstract

Oral candidiasis is closely associated with changes in the oral fungal flora and is caused primarily by Candida albicans. Conventional methods of fungal culture are time-consuming and not always conclusive. However, molecular genetic analysis of internal transcribed spacer (ITS) regions of fungal rRNA is rapid, reproducible and simple to perform. In this study we examined the fungal flora in patients with oral candidiasis and investigated changes in the flora after antifungal treatment using length heterogeneity-polymerization chain reaction (LH-PCR) analysis of ITS regions. Fifty-two patients with pseudomembranous oral candidiasis (POC) and 30 healthy controls were included in the study. Fungal DNA from oral rinse was examined for fungal species diversity by LH-PCR. Fungal populations were quantified by real-time PCR and previously-unidentified signals were confirmed by nucleotide sequencing. Relationships between the oral fungal flora and treatment-resistant factors were also examined. POC patients showed significantly more fungal species and a greater density of fungi than control individuals. Sixteen fungi were newly identified. The fungal populations from both groups were composed predominantly of C. albicans, though the ratio of C. dubliniensis was significantly higher in POC patients than in controls. The diversity and density of fungi were significantly reduced after treatment. Furthermore, fungal diversity and the proportion of C. dubliniensis were positively correlated with treatment duration. These results suggest that C. dubliniensis and high fungal flora diversity might be involved in the pathogenesis of oral candidiasis. We therefore conclude that LH-PCR is a useful technique for diagnosing and assessing the severity of oral candidal infection.

Oral mycobiome in community‐dwelling elderly and its relation to oral and general health conditions

“…However, most studies found C. albicans in the hyphal form as the cause of oral candidiasis (Coco et al, 2008;Deepa, Nair, Sivakumar, & Joseph, 2014;Samaranayake, 2009). In contrast, a previous report indicated that non-albicans Candida species were important in the pathogenesis of oral candidiasis (Ieda et al, 2014).…”

“…Candida dubliniensis isolated from HIV patients with recurrent oral candidiasis showed either low susceptibility or high resistance to fluconazole (Moran et al., ). Although C. glabrata and C. dubliniensis are considered to be less susceptible to antifungal agents, a recent study showed that the detection ratio of C. glabrata and C. dubliniensis was decreased, while C. albican s persisted, after antifungal therapy using miconazole in oral candidiasis patients (Ieda et al., ). This suggests that C. glabrata and C. dubliniensis do not necessarily have low susceptibility to antifungal agents when properly selected.…”

Molecular analysis of fungal populations in patients with oral candidiasis using next-generation sequencing

“…Candida species, especially C. albicans is the most commonly identified fungus in the oral cavity and is considered a major pathogen of oral candidiasis1415. However, several studies indicated that non- Candida species could also be pathogenic, causing altered diversity of the oral fungal flora with an increase in resistant species against antifungal agents1617.…”

Comparison of Switching and Biofilm Formation between MTL -Homozygous Strains of Candida albicans and Candida dubliniensis

“…First, C. dubliniensis is more often recovered from oropharyngeal samples (11). Second, C. dubliniensis is isolated in a majority of cases in combination with C. albicans (65)(66)(67)(68), which could explain why opaque cells of C. albicans are more stimulatory than opaque cells of C. dubliniensis in the growth of a C. dubliniensis biofilm. This evolutionary puzzle, therefore, warrants further exploration.…”