The New Zealand human gut mycobiome

Abstract

Recent studies suggest that fungi are a normal part of the human gut microbiome and contribute unique metabolic functions important for health and nutrition. Presence or absence of certain fungal species has been correlated with metabolic diseases such as obesity. The diversity of the healthy human gut mycobiome in an urban New Zealand population has not been previously explored, and few studies have attempted to determine which fungi are likely to be active in the human gut. We aimed to look for fungi likely to play and active role in the healthy human gut mycobiome using culture-dependent methods. We isolated and cultured fungi from faeces volunteered by 21 healthy, non-obese individuals. Culture-dependent techniques were employed, in order to gain an insight into the fungal species likely to survive in the human gut. Faecal samples were cultured under dark, anaerobic and aerobic conditions at body temperature (37oC), using Sabouraud dextrose agar. Twenty different fungal species were identified using Internal Transcribed Spacer -based sequencing. The number of different fungal species successfully cultured from any single individual ranged from zero to six. The most prevalent species were Candida albicans, Candida parapsilosis, and Saccharomyces cerevisiae, which is consistent with previous studies. In addition, six fungal species were identified in this study that do not appear to have been reported previously, signifying the importance of baseline studies from the general population. Our results reinforce the current understanding of the healthy human gut mycobiome and contribute new findings to this growing field. However, very few studies have cultured faecal fungi at body temperature, and we propose that our results are more likely to reflect the active resident human gut mycobiome.