Clonal outbreak of Candida vulturna in a paediatric oncology ward in Maranhão, Brazil

Abstract

Objective: To describe an outbreak due to Candida vulturna, a newly emerging Candida species belonging to the Candida haemulonii species complex in the Metschnikowiaceae family.

Methods: In this retrospective cohort study we genotyped 14 C. vulturna bloodstream isolates, occurring in a 4-month-period in paediatric cancer patients in a Brazilian hospital. To prove an outbreak, ITS sequence analysis and whole genome sequencing (WGS) was done. Antifungal susceptibility was performed with the reference CLSI method and the commercial Sensititre YeastOne (SYO) YO10 plates. A control C. vulturna isolate from another region in Brazil was included in all analyses.

Results: MALDI-TOF-MS identified isolates as C. pseudohaemulonii and C. duobushaemulonii albeit with low scores and therefore molecular methods were required for accurate identification. ITS sequence analyses clearly differentiated C. vulturna from other species in the C. haemulonii species complex. WGS proved the presence of a clonal outbreak with C. vulturna involving 14 paediatric patients. Antifungal susceptibility testing (AFST) with two methods showed the isolates had low MICs of commonly available antifungals.

Conclusion: This study describes an outbreak due to the rare yeast C. vulturna, related to C. auris, during a four-month period in patients admitted to a paediatric oncology ward in a Brazilian hospital. In contrast to previous studies the yeast was susceptible to all antifungals and patient outcome was good.

Keywords: Antifungal susceptibility; Candida haemulonii species complex; Candida vulturna; Fungal outbreak; Genotyping; Rare yeast; Whole genome sequencing.