Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation

Abstract

is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for pathogenesis is its ability to form biofilm communities. The two most medically important species- and -are often coisolated from infection sites, suggesting the importance of coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of and When using a starting ratio of to of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a monoculture and a/ ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long hyphae and cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the and adhesion genes in the / 1:3 biofilm compared to that in the monoculture biofilm. Additionally, only the 1:3/ biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner. and are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two species in pathogenesis. During the course of an infection, the prevalence of each species may change over time due to differences in metabolism and in the resistance of each species to antifungal therapies. Therefore, it is necessary to understand the dynamics between and in coculture to develop better therapeutic strategies against infections. Existing work has focused on understanding how an equal-part culture of and impacts biofilm formation and pathogenesis. What is not understood, and what is investigated in this work, is how the composition of species in coculture impacts overall biofilm formation, virulence gene expression, and the therapeutic treatment of biofilms.

The role of Lactobacillus species in the control of Candida via biotrophic interactions

“…Interestingly, a positive interaction between C. albicans and C. glabrata for host infection has been suggested. Mixed biofilms consisting of C. glabrata and C. albicans lead to more robust and complex structures and improve antifungal resistance [92]. We observed relatively frequent co-isolation of both fungi.…”

Glucose supplementation effect on the acidogenicity, viability, and extracellular matrix of Candida single‐ and dual‐species biofilms

“…The present study also highlighted the use of a dual‐species biofilm to investigate the influence of glucose on biofilm development and on the production of extracellular polysaccharides. Further studies are needed to understand the mechanisms involved in the virulence and invasion of host tissues, including the analysis of putative virulence genes, with regard to the interaction between Candida albicans and Candida glabrata . Our results demonstrated that there is a greater availability of IEPS in dual‐species biofilm when compared to single‐species biofilm.…”

Divergent Approaches to Virulence in C. albicans and C. glabrata: Two Sides of the Same Coin

“…This co-culture biofilm exhibited a high heterogenicity with C. albicans hyphae and C. glabrata cells clustered together in a 3D-structure. Interestingly, an upregulation of HWP1 and ALS3 genes is observed in this mixed-species biofilm, as well as an increased resistance to caspofungin [3]. C. albicans and C. glabrata are also known to form biofilms with bacteria from different host niches, usually relying on quorum-sensing mechanisms for the establishment of an interaction [20,155].…”

“…Candida species live as commensals on mucosal surfaces where they are constituents of the normal microbiota of the oral cavity and gastrointestinal and vaginal tracts. However, they can opportunistically become pathogenic under suitable conditions, such as host-disrupted microbiota or immunocompromised hosts, being responsible for clinical manifestations from mucocutaneous overgrowth to bloodstream infections [3,4,5]. Of the various Candida species, Candida albicans and Candida glabrata not only account for 60% of Candida species present in the human body, but also constitute the most prevalent of the pathogenic Candida species, being responsible for more than 400,000 life-threatening infections worldwide every year [3,6].…”