Biology subjects

Tormo-Palop, N.

Publications and source records attributed to Tormo-Palop, N..

2 recordsLinked to original sources

bioRxiv2024

Short-Term Evolution and Dispersal Patterns of fluconazole-resistance in Candida auris clade III

The rapid increase of infections caused by the emerging fungal pathogen Candida auris is of global concern, and understanding its expansion is a priority. The phylogenetic diversity of the yeast is clustered in five major clades, among which clade III is particularly relevant, as most of its strains exhibit resistance to fluconazole, reducing the therapeutic alternatives and provoking outbreaks that are difficult to control. In this study, we have investigated the phylogenetic structure of clade III by analyzing a global collection of 566 genomes. We have identified three subgroups within clade III, among which two are genetically most closely related. Moreover, we have estimated the evolutionary rate of clade III to be 2.25e-7 s/s/y (2.87 changes per year). We found that one of these subgroups shows intrinsic resistance to fluconazole and is responsible for the majority of cases within this clade globally. We inferred that this subgroup may have originated around December 2010 (95% HPD: April 2010 - June 2011), and since then it has spread across continents, generating multiple large outbreaks, each with a unique pattern of transmission and dissemination. These results highlight the remarkable ability of the pathogen to adapt to its environment and its rapid global spread, underscoring the urgent need to effectively address this epidemiological challenge. IMPORTANCEThe number of cases affected by Candida auris has increased worryingly worldwide. Among the currently recognized clades, clade III has the highest proportion of fluconazole-resistant cases and is spreading very rapidly, causing large nosocomial outbreaks across the globe. By analyzing complete fungal genomes from around the world, we have confirmed the origin of this clade and unraveled its dispersal patterns in the early 2010s. This finding provides knowledge that may be helpful to the public health authorities for the control of the disease.

microbiology↗

bioRxiv2024

Genotypic and phenotypic characterization of a nosocomial outbreak of Candida auris in Spain during five years

ObjectivesThe investigation of Candida auris outbreaks is needed to provide insights into its population structure and transmission dynamics. We genotypically and phenotypically characterized a C. auris nosocomial outbreak occurred at the Consorcio Hospital General Universitario de Valencia (CHGUV), Spain. MethodsData and isolates were collected at CHGUV from September 2017 (first case) until September 2021. Thirty-five isolates, one from an environmental source, were selected for whole genome sequencing (WGS), and the genomes were analyzed along with 335 publicly available genomes, assigning them to one of the five major clades. In order to identify polymorphisms associated with drug resistance, we used the fully susceptible GCA_003014415.1 strain as reference sequence. Known mutations in genes erg11 and fks1 conferring resistance to fluconazole and echinocandins, respectively, were investigated. Isolates were classified into aggregating or non-aggregating. ResultsAll isolates belonged to clade III and were from an outbreak with a single origin. They clustered close to 3 publicly available genomes from a hospital from where the first patient was transferred, being the probable origin. The mutation VF125AL in the ERG11 protein, conferring resistance to fluconazole, was present in all the isolates and one isolate also carried the mutation S639Y in the FKS1 protein. All the isolates had a non-aggregating phenotype. ConclusionsIsolates are genotypically related and phenotypically identical but one with resistance to echinocandins, which seems to indicate that they all belong to an outbreak originated from a single isolate, remaining largely invariable over the years. This result stresses the importance of implementing infection control practices as soon as the first case is detected or when a patient is transferred from a setting with known cases.

microbiology↗