Emergence of Antifungal Resistant Subclades in the Global Predominant Phylogenetic Population of Candida albicans.

Candida albicans remains the most common species causing invasive candidiasis. In this study, we present the population structure of 551 global C. albicans strains. Of these, the antifungal susceptibilities of 370 strains were tested. Specifically, 66.6% of the azole-nonsusceptible (NS)/non-wild-type (NWT) strains that were tested belonged to Clade 1. A phylogenetic analysis, a principal components analysis, the population structure, and a loss of heterozygosity events revealed two nested subclades in Clade 1, namely, Clade 1-R and Clade 1-R-α, that exhibited higher azole-NS/NWT rates (75.0% and 100%, respectively). In contrast, 6.4% (21/326) of the non-Clade 1-R isolates were NS/NWT to at least 1 of 4 azoles. Notably, all of the Clade 1-R-α isolates were pan-azole-NS/NWT that carried unique A114S and Y257H double substitutions in Erg11p and had the overexpression of ABC-type efflux pumps introduced by the substitution A736V in transcript factor Tac1p. It is worth noting that the Clade 1-R and Clade 1-R-α isolates were from different cities that are distributed over a large geographic span. Our study demonstrated the presence of specific phylogenetic subclades that are associated with antifungal resistance among C. albicans Clade 1, which calls for public attention on the monitoring of the future spread of these clones. IMPORTANCE Invasive candidiasis is the most common human fungal disease among hospitalized patients, and Candida albicans is the predominant pathogen. Considering the large number of infected cases and the limited alternative therapies, the azole-resistance of C. albicans brings a huge clinical threat. Here, our study suggested that antifungal resistance in C. albicans could also be associated with phylogenetic lineages. Specifically, it was revealed that more than half of the azole-resistant C. albicans strains belonged to the same clade. Furthermore, two nested subclades of the clade exhibited extremely high azole-resistance. It is worth noting that the isolates of two subclades were from different cities that are distributed over a large geographic span in China. This indicates that the azole-resistant C. albicans subclades may develop into serious public health concerns.

Diagnosis, management and prevention of Candida auris in hospitals: position statement of the Australasian Society for Infectious Diseases.

Candida auris is an emerging drug-resistant yeast responsible for hospital outbreaks. This statement reviews the evidence regarding diagnosis, treatment and prevention of this organism and provides consensus recommendations for clinicians and microbiologists in Australia and New Zealand. C. auris has been isolated in over 30 countries (including Australia). Bloodstream infections are the most frequently reported infections. Infections have crude mortality of 30-60%. Acquisition is generally healthcare-associated and risks include underlying chronic disease, immunocompromise and presence of indwelling medical devices. C. auris may be misidentified by conventional phenotypic methods. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry or sequencing of the internal transcribed spacer regions and/or the D1/D2 regions of the 28S ribosomal DNA are therefore required for definitive laboratory identification. Antifungal drug resistance, particularly to fluconazole, is common, with variable resistance to amphotericin B and echinocandins. Echinocandins are currently recommended as first-line therapy for infection in adults and children ≥2 months of age. For neonates and infants <2 months of age, amphotericin B deoxycholate is recommended. Healthcare facilities with C. auris should implement a multimodal control response. Colonised or infected patients should be isolated in single rooms with Standard and Contact Precautions. Close contacts, patients transferred from facilities with endemic C. auris or admitted following stay in overseas healthcare institutions should be pre-emptively isolated and screened for colonisation. Composite swabs of the axilla and groin should be collected. Routine screening of healthcare workers and the environment is not recommended. Detergents and sporicidal disinfectants should be used for environmental decontamination.