Candida auris is a multidrug-resistant pathogen that represents a serious public health threat due to its rapid global emergence, increasing incidence of healthcare-associated outbreaks, and high rates of antifungal resistance. Whole-genome sequencing and genomic surveillance have the potential to bolster C. auris surveillance networks moving forward. Laboratories conducting genomic surveillance need to be able to compare analyses from various national and international surveillance partners to ensure that results are mutually trusted and understood. Therefore, we established an empirical outbreak benchmark dataset consisting of 23 C. auris genomes to help validate comparisons of genomic analyses and facilitate communication among surveillance networks. Our outbreak benchmark dataset represents a polyclonal phylogeny with three subclades. The genomes in this dataset are from well-vetted studies that are supported by multiple lines of evidence, which demonstrate that the whole-genome sequencing data, phylogenetic tree, and epidemiological data are all in agreement. This C. auris benchmark set allows for standardized comparisons of phylogenomic pipelines, ultimately promoting effective C. auris collaborations.

In our study, mutations associated to azole resistance and echinocandin resistance were detected in Candida glabrata isolates using a whole-genome sequence. C. glabrata is the second most common cause of candidemia in the United States, which rapidly acquires resistance to antifungals, in vitro and in vivo .

Reports of fluconazole-resistant Candida parapsilosis bloodstream infections are increasing. We describe a cluster of fluconazole-resistant C. parapsilosis bloodstream infections identified in 2021 on routine surveillance by the Georgia Emerging Infections Program in conjunction with the Centers for Disease Control and Prevention. Whole-genome sequencing was used to analyze C. parapsilosis bloodstream infections isolates. Epidemiological data were obtained from medical records. A social network analysis was conducted using Georgia Hospital Discharge Data. Twenty fluconazole-resistant isolates were identified in 2021, representing the largest proportion (34%) of fluconazole-resistant C. parapsilosis bloodstream infections identified in Georgia since surveillance began in 2008. All resistant isolates were closely genetically related and contained the Y132F mutation in the ERG11 gene. Patients with fluconazole-resistant isolates were more likely to have resided at long-term acute care hospitals compared with patients with susceptible isolates (p-value 0.01). There was a trend towards increased mechanical ventilation and prior azole use in patients with fluconazole-resistant isolates. Social network analysis revealed that patients with fluconazole-resistant isolates interfaced with a distinct set of healthcare facilities centered around two long-term acute care hospitals compared with patients with susceptible isolates. WGS results showing that fluconazole-resistant C. parapsilosis isolates from Georgia surveillance demonstrated low genetic diversity compared with susceptible isolates and their association with a facility network centered around two long-term acute care hospitals suggests clonal spread of fluconazole-resistant C. parapsilosis. Further studies are needed to better understand the sudden emergence and transmission of fluconazole-resistant C. parapsilosis.

Since 2016, in Colombia, ongoing transmission of Candida auris has been reported in multiple cities. Here, we provide an updated description of C. auris genomic epidemiology and the dynamics of antifungal resistance in Colombia. We sequenced 99 isolates from C. auris cases with collection dates ranging from June 2016 to January 2021; the resulting sequences coupled with 103 previously generated sequences from C. auris cases were described in a phylogenetic analysis. All C. auris cases were clade IV. Of the 182 isolates with antifungal susceptibility data, 67 (37%) were resistant to fluconazole, and 39 (21%) were resistant to amphotericin B. Isolates predominately clustered by country except for 16 isolates from Bogotá, Colombia, which grouped with isolates from Venezuela. The largest cluster ( N = 166 isolates) contained two subgroups. The first subgroup contained 26 isolates, mainly from César; of these, 85% ( N = 22) were resistant to fluconazole. The second subgroup consisted of 47 isolates from the north coast; of these, 81% ( N = 38) were resistant to amphotericin B. Mutations in the ERG11 and TAC1B genes were identified in fluconazole-resistant isolates. This work describes molecular mechanisms associated with C. auris antifungal resistance in Colombia. Overall, C. auris cases from different geographic locations in Colombia exhibited high genetic relatedness, suggesting continued transmission between cities since 2016. These findings also suggest a lack of or minimal introductions of different clades of C. auris into Colombia. IMPORTANCE: Candida auris is an emerging fungus that presents a serious global health threat and has caused multiple outbreaks in Colombia. This work discusses the likelihood of introductions and local transmission of C. auris and provides an updated description of the molecular mechanisms associated with antifungal resistance in Colombia. Efforts like this provide information about the evolving C. auris burden that could help guide public health strategies to control C. auris spread.

Sporothrix brasiliensis is an emerging zoonotic fungal pathogen that can be difficult to treat. Antifungal susceptibility testing was performed on the mold phase of a convenience sample of 61 Sporothrix spp. isolates from human and cat sporotrichosis cases in Brazil using the Clinical and Laboratory Standards Institute standard M38. A bimodal distribution of azole susceptibility was observed with 50% (28/56) of S. brasiliensis isolates showing elevated itraconazole minimum inhibitory concentrations ≥16 µg/mL. Phylogenetic analysis found the in vitro resistant isolates were not clonal and were distributed across three different S. brasiliensis clades. Single nucleotide polymorphism (SNP) analysis was performed to identify potential mechanisms of in vitro resistance. Two of the 28 resistant isolates (MIC ≥16 mg/L) had a polymorphism in the cytochrome P450 gene, cyp51 , corresponding to the well-known G448S substitution inducing azole resistance in Aspergillus fumigatus . SNPs corresponding to other known mechanisms of azole resistance were not identified in the remaining 26 in vitro resistant isolates.

Echinocandins are the recommended antifungal therapy for Candida auris infections in many countries. While echinocandin resistance remains uncommon, recent reports demonstrate an increase in such cases, with the potential for echinocandin-resistant C. auris transmission between persons. The expansion of C. auris whole-genome sequencing capacity in public health laboratories provides a great opportunity to leverage genomic data to detect echinocandin resistance-conferring mutations. However, curated datasets for validating genomic tools for these purposes are lacking. Therefore, we developed a benchmark dataset comprising 100 whole-genome sequenced C. auris isolates categorized as echinocandin-susceptible ( n = 53) and resistant ( n = 47) by antifungal susceptibility testing. We implemented the fungal bioinformatics pipeline, MycoSNP-nf, to perform whole-genome sequencing analysis, including C. auris clade typing and the detection of FKS1 mutations in hotspot (HS) regions. Phylogenetic analysis classified isolates into four major clades (Clades I–IV). Of the 47 isolates considered resistant by AFST, 44 showed HS mutations identified by MycoSNP-nf—with 41 positioned in two well-described HS regions and 3 within a potential third hotspot that was recently reported. This benchmark dataset is designed to be a resource to build sequencing capacity to detect echinocandin resistance-conferring mutations in FKS1 and to help standardize comparisons across other bioinformatics tools. IMPORTANCE: Echinocandins are the recommended first-line treatment for invasive infections caused by Candida auri s, a multi-drug-resistant yeast that has emerged in healthcare facilities globally. Increasing instances of echinocandin-resistant cases highlight the need for rapid detection and response. We developed a benchmark dataset comprising 100 C. auris echinocandin-resistant and -susceptible isolates to demonstrate the utility of the bioinformatics tool, MycoSNP-nf, for detecting echinocandin resistance-related FKS1 mutations and to assess their concordance with antifungal susceptibility testing results. This benchmark may help validate MycoSNP-nf and other bioinformatics tools aimed at detecting these mechanisms using whole-genome sequencing data.