Yeasts isolated from tropical fruit ice creams: diversity, antifungal susceptibility and adherence to buccal epithelial cells

Gabriella Breder Lara Lima,Fátima De Cássia Oliveira Gomes,Mariana De Lourdes Almeida Vieira,Susana Johann,Carlos Augusto Rosa

doi:10.1590/1981-6723.19718

Gabriella Breder Lara Lima, Fátima De Cássia Oliveira Gomes + Show 3 more

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https://doi.org/10.1590/1981-6723.19718

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Abstract

Abstract Fruit-based ice creams are products widely consumed in tropical countries and, because of their composition, can be a good source for microbial growth, including opportunistic pathogens. The aims of this study were to characterize the yeast populations present in Brazilian fruit-based ice creams, and to investigate the antifungal susceptibility to amphotericin B, fluconazole and itraconazole, and the ability of the isolates that were able to grow at 37 ºC to adhere to buccal epithelial cells (BEC). Two hundred and sixty-seven yeast isolates obtained from the ice cream samples were identified as belonging to 29 species, with counts that ranged from 1.5 to 5.2 log CFU/mL. The predominant species were Candida intermedia, Torulaspora delbrueckii, C. parapsilosis, Clavispora lusitaniae, Saccharomyces cerevisiae and Pichia kudriavzevii. At least 16 yeast species isolated in this study have been reported as opportunistic pathogens. Forty-one yeast isolates showed resistance or dose-dependent susceptibility to at least one of the antifungal drugs tested. One isolate of C. parapsilosis was resistant to all the antifungals tested and showed ability to adhere to BEC. The percentage of adhesion to BEC was high mainly for isolates of P. kudriavzevii, Meyerozyma guilliermondii, C. parapsilosis, S. cerevisiae and Debaromyces hansenii. The data suggest that the presence of these opportunistic yeasts as contaminants in ice creams may represent a potential risk to the final consumer, especially to immunocompromised individuals who may consume these products.

Highlights

Ice cream is a major product of the dairy industry and is widely consumed in tropical countries due to the high temperatures in these regions (Farias et al, 2006; Arbuckle, 2013; Lima et al, 2016)
The high content of nutrients like lactose, sugar and proteins, and the final pH, make them an excellent growth medium for yeasts, even though stored at low temperatures (Lee et al, 2009; Ambily & Beena, 2012). These products may represent a specialised ecological environment for the selective occurrence and growth of certain yeast species, such as Debaryomyces hansenii (=Candida famata), Naganishia albida (=Cryptococcus albidus), Saitozyma flava (=Cryptococcus flavus), Rhodosporidium glutinis (=Rhodotorula glutinis) and Rhodotorula mucilaginosa, which have been isolated from ice creams (Fleet & Mian, 1987)
Two hundred and sixty-seven yeast isolates belonging to 29 species were isolated from the fruit-based ice creams

Summary

Introduction

Ice cream is a major product of the dairy industry and is widely consumed in tropical countries due to the high temperatures in these regions (Farias et al, 2006; Arbuckle, 2013; Lima et al, 2016). The high content of nutrients like lactose, sugar and proteins, and the final pH, make them an excellent growth medium for yeasts, even though stored at low temperatures (Lee et al, 2009; Ambily & Beena, 2012) These products may represent a specialised ecological environment for the selective occurrence and growth of certain yeast species, such as Debaryomyces hansenii (=Candida famata), Naganishia albida (=Cryptococcus albidus), Saitozyma flava (=Cryptococcus flavus), Rhodosporidium glutinis (=Rhodotorula glutinis) and Rhodotorula mucilaginosa, which have been isolated from ice creams (Fleet & Mian, 1987)

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