Distribution of Pathogenic Yeasts in Different Clinical Samples: Their Identification, Antifungal Susceptibility Pattern, and Cell Invasion Assays

• Published in: Infection and drug resistance Vol. 13; pp. 1133 - 1145
• Main Authors: Pote, Satish T, Sonawane, Mahesh S, Rahi, Praveen, Shah, Sunil R, Shouche, Yogesh S, Patole, Milind S, Thakar, Madhuri R, Sharma, Rohit
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2020; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Antifungal agents; antifungal drug resistance; Automation; Azoles; Base sequence; Biofilms; Candida; Candida albicans; Cells (Biology); Characterization; chromogenic media; Clotrimazole; Coloration; Comparative analysis; Deoxyribonucleic acid; DNA; DNA sequencing; Drug resistance; EDTA; Epithelial cells; Fluconazole; Genes; Genetic research; Geographical distribution; Health aspects; Identification; Infection; Introduced species; Invasive species; Isolation; Itraconazole; Ketoconazole; maldi-tof ms; Medical research; Microbiota; Microbiota (Symbiotic organisms); Mortality; Nucleotide sequence; Nystatin; Opportunist infection; Original Research; Pathogenic microorganisms; Pathogens; Phylogenetics; Ribosomal DNA; RNA; rRNA 28S; Sequence analysis; Virulence factors; Yeast; yeast clinical isolates; India; MALDI-TOF MS; antifungal drug resistance; chromogenic media; yeast clinical isolates; DNA sequencing
• ISSN: 1178-6973; 1178-6973
• DOI: 10.2147/IDR.S238002

Species of genus are part of the common microbiota of humans; however, some of the species are known opportunistic pathogens. Formation of biofilms, resistance to antifungal drugs, and increase in asymptomatic infections demands more studies on isolation, identification and characterization of from clinical samples. The present manuscript deals with assessment of authentic yeast identification by three methods viz., DNA sequencing of gene, protein profiles using MALDI-TOF MS, and colony coloration on chromogenic media. Antifungal susceptibility and in vitro cell invasion assays were performed to further characterize these isolates. Comparison of three methods showed that DNA sequence analysis correctly identified more than 99.4% of the isolates up to species level as compared to 89% by MALDI-TOF MS. In this study, we isolated a total of 176 yeasts from clinical samples and preliminary morphological characters indicated that these yeast isolates belong to the genus . The species distribution of isolates was as follows: 75 isolates of (42.61%), 50 of (28.40%), 22 of (12.5%), 14 of (7.95%) and 4 of (2.27%). Other species like sp., and were less than 2%. Antifungal susceptibility assay performed with 157 isolates showed that most of the isolates were resistant to the four azoles viz., clotrimazole, fluconazole, itraconazole, and ketoconazole, and the frequency of resistance was more in non-albicans isolates. The susceptibility to azole drugs ranged from 7% to 48%, while 75% of the tested yeasts were susceptible to nystatin. Moreover, 88 isolates were also tested for their capacity to invade human cells using HeLa cells. In vitro invasion assay showed that most of the isolates showed epithelial cell invasion as compared to isolates belonging to and . The identification of yeasts of clinical origin by sequencing of gene performed better than MALDI-TOF MS. The present study reiterates the world scenario wherein there is a shift from strains to emerging opportunistic pathogens which were earlier regarded as environmental strains. The present study enlightens the current understanding of identification methods for clinical yeast isolates, increased antifungal drug resistance, epithelial cell invasion as a virulence factor, and diversity of yeasts in Indian clinical samples.