Multidrug-resistant Candida auris: an epidemiological review

ABSTRACT

Introduction

Since the emergence of Candida auris infection in 2009, the disease has been reported from multiple countries within a decade. The infection is classified under urgent threat, as it is multi-drug resistant, causes high mortality, spreads easily in hospital setting and is difficult to identify. Whole-genome sequencing has provided insights into this organisms biology and epidemiology. A comprehensive review of those issues would help the clinicians and scientists facing C. auris infection.

Areas covered

We reviewed the epidemiological trends of C. auris infection, including the genomic epidemiology based on an electronic search using Pubmed and Google scholar. We also discuss the biology, virulence attributes of this pathogen, its clinical presentations and associated risk factors. The mechanisms of antifungal resistance known so far are also described in addition to factors involved in the nosocomial transmission, environmental survival and ecology of C. auris.

Expert opinion

Despite the attention of multiple researchers evaluating every aspect of this organism and its epidemiology, there are several gaps in tracing its origin and understanding the dynamics of nosocomial transmission and global spread. Multidisciplinary, coordinated studies are required to understand the biology, ecology, method of survival and spread of the organism in healthcare setup

KEYWORDS:

• Candida auris
• clades
• environmental survival
• epidemiology
• invasive candidiasis
• nosocomial
• resistance
• transmission
• virulence

Article highlights

• Candida auris infection has been reported from multiple countries worldwide, particularly in critically ill patients with long hospital stay, multiple interventions and antifungal exposure. It is associated with high (17-72%) mortality.

• Its origin is unclear with inconclusive speculations like overuse of antifungals, global warming and exposure to ultraviolet radiation. The dynamics of spread and environmental niche are also unknown.

• Colonization in humans is seen in axilla, groin, nares and rectum. Alcohol and chlorine-based disinfectants are effective in clearing C. auris provided the recommended duration of contact is allowed. However, more studies are required for decolonization and environmental cleaning against C. auris.

• Whole genome sequence analysis revealed four distinct geographical phylogenetic clades (Clade I, South Asia; Clade II, East Asia; Clade III, South Africa; Clade IV, South America) and a potential Clade V, Iran and has helped in understanding transmission dynamics in few countries like United States of America and United Kingdom.

• C. auris exhibits fewer virulence attributes compared to C. albicans, which include extracellular hydrolases, thermotolerance, nutrient versatility, adaptation to different host niches, biofilm formation and immune evasion.

• Tentative breakpoints derived from related species have been used to analyze results of antifungal susceptibility testing. High ABC and MFS efflux pumps activity and ERG11 mutations are important for azole resistance; mutations in FKS1 causing echinocandin resistance; and single nucleotide polymorphism at different genomic loci are associated with low sensitivity to polyenes.

Declaration of interest

This paper was not funded. The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.