Search

The recently emerged fungal pathogen Candida auris often displays resistance to one or more antifungal drugs. Its infections have been identified in at least 40 countries on six continents to date. Here we report a case of C. auris candidemia in a patient in Xiamen, a city in south China. We also review currently reported cases of C. auris infection in China and compare the genetic and biological features of C. auris strains isolated from this country. Our phylogenetic analysis indicates that there are at least two C. auris genetic clades present in China (the South African clade and the south Asian clade) that display opposite mating type loci (one is MTLa and the other is MTLα). We also found that there are several distinct features among the clinical isolates studied, including the expression of virulence factors, antifungal susceptibilities, and cellular morphologies, and that these features could be associated with the mating-type of the isolate. For example, C. auris MTLa isolates generally secreted higher levels of secreted aspartyl proteases (Saps) at ambient environmental temperatures. Taken together, this study demonstrates that C. auris clinical isolates from China exhibit diversity in both biological and genetic features. [ABSTRACT FROM AUTHOR]

Candida albicansandStreptococcus oralisare ubiquitous oral commensal organisms. Under host-permissive conditions these organisms can form hypervirulent mucosal biofilms.C. albicansbiofilm formation is controlled by 6 master transcriptional regulators: Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1. The objective of this work was to test whether any of these regulators play a role in cross-kingdom interactions betweenC. albicansandS. oralisin oral mucosal biofilms, and identify downstream target gene(s) that promote these interactions. Organotypic mucosal constructs and a mouse model of oropharyngeal infection were used to analyze mucosal biofilm growth and fungal gene expression. By screening 6C. albicanstranscription regulator reporter strains we discovered thatEFG1was strongly activated by interaction withS. oralisin late biofilm growth stages.EFG1gene expression was increased in polymicrobial biofilms on abiotic surfaces, mucosal constructs and tongue tissues of mice infected with both organisms.EFG1was required for robustCandida-streptococcal biofilm growth in organotypic constructs and mouse oral tissues.S. oralisstimulatedC. albicans ALS1gene expression in anEFG1-dependent manner, and Als1 was identified as a downstream effector of the Efg1 pathway which promotedC. albicans-S. oraliscoaggregation interactions in mixed biofilms. We conclude thatS. oralisinduces an increase inEFG1expression inC. albicansin late biofilm stages. This in turn increases expression ofALS1, which promotes coaggregation interactions and mucosal biofilm growth. Our work provides novel insights onC. albicansgenes which play a role in cross-kingdom interactions withS. oralisin mucosal biofilms. [ABSTRACT FROM AUTHOR]

Candida albicans is a commensal microorganism of the human microbiome; it is also the most prevalent fungal pathogen of humans. Many infections caused by C. albicans are a direct consequence of its proclivity to form biofilms-resilient, surface-associated communities of cells where individual cells acquire specialized properties that are distinct from those observed in suspension cultures. We recently identified the transcriptional network that orchestrates the formation of biofilms in C. albicans. These results set the stage for understanding how biofilms are formed and, once formed, how the specialized properties of biofilms are elaborated. This information will provide new insight for understanding biofilms in more detail and may lead to improvements in preventing and treating biofilm-based infections in the future. [ABSTRACT FROM AUTHOR]