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

作者：Helena Sztajer, Szymon Piotr Szafrański, Jürgen Tomasch, Michael Reck, Manfred Nimtz, Manfred Rohde, Irene Wagner‐Döbler · 发表于：The ISME Journal · 年份：2014 · DOI：10.1038/ismej.2014.73 · 被引用次数：239 · 研究领域：Antifungal resistance and susceptibility、Oral microbiology and periodontitis research、Bacterial biofilms and quorum sensing

Polymicrobial biofilms are of large medical importance, but relatively little is known about the role of interspecies interactions for their physiology and virulence. Here, we studied two human pathogens co-occuring in the oral cavity, the opportunistic fungus Candida albicans and the caries-promoting bacterium Streptococcus mutans. Dual-species biofilms reached higher biomass and cell numbers than mono-species biofilms, and the production of extracellular polymeric substances (EPSs) by S. mutans was strongly suppressed, which was confirmed by scanning electron microscopy, gas chromatography-mass spectrometry and transcriptome analysis. To detect interkingdom communication, C. albicans was co-cultivated with a strain of S. mutans carrying a transcriptional fusion between a green fluorescent protein-encoding gene and the promoter for sigX, the alternative sigma factor of S. mutans, which is induced by quorum sensing signals. Strong induction of sigX was observed in dual-species biofilms, but not in single-species biofilms. Conditioned media from mixed biofilms but not from C. albicans or S. mutans cultivated alone activated sigX in the reporter strain. Deletion of comS encoding the synthesis of the sigX-inducing peptide precursor abolished this activity, whereas deletion of comC encoding the competence-stimulating peptide precursor had no effect. Transcriptome analysis of S. mutans confirmed induction of comS, sigX, bacteriocins and the downstream late competence genes, includ...