Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis.

Rodnei Dennis Rossoni,Antonio Olavo Cardoso Jorge,Beth Burgwyn Fuchs,Eleftherios Mylonakis,Simone Furgeri Godinho Vilela,Juliana Campos Junqueira,Patrícia Pimentel De Barros,Jéssica Diane Dos Santos,Márcia Cristina De Azevedo Prata,Júnia Oliveira Barbosa,Ana Lia Anbinder

doi:10.1371/journal.pone.0131700

Rodnei Dennis Rossoni, Antonio Olavo Cardoso Jorge + Show 9 more

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https://doi.org/10.1371/journal.pone.0131700

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Abstract

In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis.

Highlights

Candida albicans is the leading cause of fungal infections in the oral cavity, representing 50 to 70% of isolated yeast [1,2,3,4]
In biofilms formed at the bottom of 96-well plates, we observed that C. albicans presented higher CFU/mL in single biofilms compared to mixed biofilms with associations of non-albicans species (Fig 1A and 1B), suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation
Larvae infected with C. albicans presented 100% mortality following a period of 18 h post infection, whilst C. krusei and C. glabrata species were less pathogenic to the G. mellonella caterpillars, with a mortality rate of 34% and 19%, respectively, at the end of the experiment (Fig 3A)

Summary

Introduction

Candida albicans is the leading cause of fungal infections in the oral cavity, representing 50 to 70% of isolated yeast [1,2,3,4]. Alves et al [15] investigated the in vitro co-infection of a reconstituted human vaginal epithelium by C. albicans and C. glabrata and observed higher tissue damage in co-infection compared to single C. albicans infection, suggesting a potential synergism between these species. Since all these studies were performed using in vitro model systems, additional in vivo studies are required to better understand the interaction of Candida species during the colonization and invasion of host tissues in mixed infection

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