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Clinical and tree hollow populations of human pathogenic yeast in Hamilton, Ontario, Canada are different
Chris Carvalho1, Jiaqi Yang, Aaron Vogan
1Department of Biology, McMaster University, Hamilton, ON, Canada.
Abstract:
Yeast are among the most frequent pathogens in humans. The dominant yeast causing human infections belong to the genus Candida and Candida albicans is the most frequently isolated species. However, several non-C. albicans species are becoming increasingly common in patients worldwide. The relationships between yeast in humans and the natural environments remain poorly understood. Furthermore, it is often difficult to identify or exclude the origins of disease-causing yeast from specific environmental reservoirs. In this study, we compared the yeast isolates from tree hollows and from clinics in Hamilton, Ontario, Canada. Our surveys and analyses showed significant differences in yeast species composition, in their temporal dynamics, and in yeast genotypes between isolates from tree hollows and hospitals. Our results are inconsistent with the hypothesis that yeast from trees constitute a significant source of pathogenic yeast in humans in this region. Similarly, the yeast in humans and clinics do not appear to contribute to yeast in tree hollows.
Insights
Yeast in tree hollows and clinics show distinct species and genetic differences. This study suggests trees are not a significant source of human yeast infections in Hamilton, Canada.
Area of Science:
- Medical Mycology
- Environmental Microbiology
- Epidemiology
Background:
- Yeast, particularly Candida species, are common human pathogens.
- Non-albicans Candida species are increasingly prevalent in clinical settings worldwide.
- The environmental origins of pathogenic yeasts remain poorly understood, hindering source identification.
Purpose of the Study:
- To investigate the relationship between yeast populations in natural environments (tree hollows) and clinical settings.
- To compare yeast species composition, temporal dynamics, and genotypes between tree hollow and hospital isolates.
- To assess the potential contribution of tree-associated yeasts to human infections and vice versa.
Main Methods:
- Collection and analysis of yeast isolates from tree hollows and clinics in Hamilton, Ontario, Canada.
- Comparative analysis of yeast species identification.
- Genotyping of yeast isolates to assess genetic relatedness.
- Evaluation of temporal dynamics in yeast populations.
Main Results:
- Significant differences were observed in yeast species composition between tree hollows and clinics.
- Temporal dynamics and genetic profiles of yeast isolates also differed markedly between the two environments.
- No significant overlap or contribution was found between yeast populations in tree hollows and clinical settings.
Conclusions:
- The hypothesis that tree hollows are a significant reservoir for pathogenic yeasts causing human infections in this region is not supported.
- Yeast found in human infections and clinics do not appear to originate from or significantly contribute to yeast populations in local tree hollows.
- Further research is needed to elucidate the complex ecological interactions and transmission routes of pathogenic yeasts.
