Synergistic Interaction between Candida albicans and Commensal Oral Streptococci in a Novel In Vitro Mucosal Model

Abstract

Candida albicans is a commensal colonizer of the gastrointestinal tract of humans, where it coexists with highly diverse bacterial communities. It is not clear whether this interaction limits or promotes the potential of C. albicans to become an opportunistic pathogen. Here we investigate the interaction between C. albicans and three species of streptococci from the viridans group, which are ubiquitous and abundant oral commensal bacteria. The ability of C. albicans to form biofilms with Streptococcus oralis, Streptococcus sanguinis, or Streptococcus gordonii was investigated using flow cell devices that allow abiotic biofilm formation under salivary flow. In addition, we designed a novel flow cell system that allows mucosal biofilm formation under conditions that mimic the environment in the oral and esophageal mucosae. It was observed that C. albicans and streptococci formed a synergistic partnership where C. albicans promoted the ability of streptococci to form biofilms on abiotic surfaces or on the surface of an oral mucosa analogue. The increased ability of streptococci to form biofilms in the presence of C. albicans could not be explained by a growth-stimulatory effect since the streptococci were unaffected in their growth in planktonic coculture with C. albicans. Conversely, the presence of streptococci increased the ability of C. albicans to invade organotypic models of the oral and esophageal mucosae under conditions of salivary flow. Moreover, characterization of mucosal invasion by the biofilm microorganisms suggested that the esophageal mucosa is more permissive to invasion than the oral mucosa. In summary, C. albicans and commensal oral streptococci display a synergistic interaction with implications for the pathogenic potential of C. albicans in the upper gastrointestinal tract.

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“…Cavalcanti et al, 2016 reported that biofilm growth and hyphal filament production by C. albicans is enhanced by S. oralis and there was growth synergy between oral bacteria Actinomyces oris and C. albicans, and between S. oralis and C. albicans, resulting in augmentation of total biofilm biomass in each case. Since S. oralis facilitates invasion of oral mucosal epithelium by C. albicans (Diaz et al, 2012), concurrently S. oralis growth is enhanced by the fungus. In addition, the pathogenic properties and invasive potential of streptococci bacteria could be augmented by C. albicans (Falsetta et al, 2014 andXu et al, 2014).Our results revealed that the highest mortality rate occurred in Nile tilapia fish in the S. iniae+ C. albicans infected group (76.19%) which was maximum during the 1 st week post infection (38.10%), followed by those infected with S. iniae alone (61.9%) and then the C. albicans infected group (57.14%).…”

Cross-feeding and interkingdom communication in dual-species biofilms of Streptococcus mutans and Candida albicans

“…The S. gordonii cell wall-associated polypeptide SspB3 interacts directly with the C. albicans hyphae-specific agglutinin-like sequence 3 . A synergistic partnership between S. oralis, S. sanguinis and C. albicans was observed, where the fungus promoted biofilm formation by the streptococci on abiotic surfaces and on mucosa (Diaz et al, 2012). Thus not only S. mutans, but also C. albicans might have crucial roles for the cariogenic biofilm succession (Metwalli et al, 2013).…”

Candida albicans biofilm heterogeneity does not influence denture stomatitis but strongly influences denture cleansing capacity

“…This is likely influenced by the diverse microbiota in this environment, which we have recently described (22). Indeed, there is increasing evidence that Candida and bacteria form polymicrobial biofilms, and that some bacterial species common to the oral cavity can enhance the pathogenicity of C. albicans (35)(36)(37)(38), and that the presence of specific oral bacteria is enough to transform a C. albicans LBF into a HBF (39). We have also reported a significant association between lactobacilli and yeasts in this context, and this may be more important than C. albicans alone, as is the perceived paradigm for this DS.…”