Candida auris: Diagnostic Challenges and Emerging Opportunities for the Clinical Microbiology Laboratory

Abstract

Purpose of Review This review summarises the epidemiology of Candida auris infection and describes contemporary and emerging diagnostic methods for detection and identification of C. auris . Recent Findings A fifth C. auris clade has been described. Diagnostic accuracy has improved with development of selective/differential media for C. auris . Advances in spectral databases of matrix-associated laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) systems have reduced misidentification. Direct detection of C. auris in clinical specimens using real time PCR is increasingly used, as is whole genome sequencing (WGS) to track nosocomial spread and to study phylogenetic relationships and drug resistance. Summary C. auris is an important transmissible, nosocomial pathogen. The microbiological laboratory diagnostic capacity has extended beyond culture-based methods to include PCR and WGS. Microbiological techniques on the horizon include the use of MALDI-TOF MS for early echinocandin antifungal susceptibility testing (AST) and expansion of the versatile and information-rich WGS methods for outbreak investigation.

Virulence Factors of Candida spp. and Host Immune Response Important in the Pathogenesis of Vulvovaginal Candidiasis

“…Most often, it causes infections in patients who are artificially ventilated, hospitalized in the intensive care unit, catheterized, HIV-infected, diabetic and immunosuppressed. Other factors predisposing to C. auris infections include parenteral nutrition, previous surgery, or long-term use of antimicrobials [ 19 , 20 , 22 ]. C. auris is currently a global threat, causing severe epidemic outbreaks of invasive infections most often associated with medical care [ 21 ].…”

Candida auris – eine Hefe in Zeiten der Pandemie

“…Im Gegensatz zu phänotypischen Methoden ist die Matrix assisted Laser Desorption Ionisation Time-of-Flight-Massenspektrometrie (MALDI-TOF MS) in der Lage, C. auris verlässlich zu identifizieren. Dabei ist nicht nur die Identifikation von festen Agarplatten, sondern auch direkt aus positiven Blutkulturflaschen möglich [9].…”

“…ITS-Regionen entwickeln sich schneller als kodierende Regionen und zeigen Variationen zwischen verschiedenen Hefearten. Darüber hinaus ist die Ganz-Genom-Sequenzierungsanalyse ein leistungsfähiges Werkzeug, um zwischen den phylogeografischen Kladen zu differenzieren und lokale Krankenhausausbrüche weiter abzugrenzen [9]. Diese recht teuren Methoden sind jedoch nicht in allen mikrobiologischen Laboren ohne Weiteres verfügbar, sodass es wichtig ist, eine einfachere, aber verlässliche Methode für die Routinediagnostik zu wählen.…”

Diagnosis and Treatment of Invasive Candidiasis

“…A novel Candida species— C. auris —has recently emerged as an etiologic agent of invasive candidiasis worldwide [ 34 , 35 ]. The fungus first identified in 2009 in Japan was later found on all continents except Antarctica [ 36 , 37 , 38 ]. This species is closely related to the C. haemulonii complex and has five geographically and genetically distant clades [ 39 , 40 ].…”

“…The rise in cases occurred simultaneously in different regions [ 41 , 42 ]. C. auris easily forms biofilms, persist on different surfaces [ 37 , 43 , 44 ], and has high potential for nosocomial transmission [ 45 , 46 ].…”