Sensitivity of S. cerevisiae in haematology patients

Invasive Saccharomyces cerevisiae in a liver transplant patient: case report and review of infection in transplant recipients

Saccharomyces cerevisiae, an ascosporogenous yeast commonly used in the production of food, is an emerging infection in immunocompromised patients. We report the case of a 60-year-old man whose orthotopic liver transplant was complicated by S. cerevisiae fungemia and peritoneal abscess, successfully treated with caspofungin and drainage. We also review the literature of invasive saccharomycoses in recipients of hematologic and solid organ transplants.

Relatedness of medically important strains of Saccharomyces cerevisiae as revealed by phylogenetics and metabolomics

Ten medically important Saccharomyces strains, comprising six clinical isolates of Saccharomyces cerevisiae and four probiotic strains of Saccharomyces boulardii, were characterized at the genetic and metabolic level and compared with non-medical, commercial yeast strains used in baking and wine-making. Strains were compared by genetic fingerprinting using amplified fragment length polymorphism (AFLP) analysis, by ribosomal DNA ITS1 sequencing and by metabolic footprinting using both direct injection mass spectrometry (DIMS) and gas chromatography-time of flight-mass spectrometry (GC-ToF-MS). Overall, the clinical isolates fell into different groupings when compared with the non-medical strains, with good but not perfect correlation amongst strains at both the genetic and metabolic levels. Probiotic strains of S. boulardii that are used therapeutically to treat human gastro-intestinal tract disorders showed tight clustering both genetically and metabolically. Metabolomics was found to be of value both as a taxonomic tool and as a means to investigate anomalous links between genotype and phenotype. Key discriminatory metabolites were identified when comparing the three main groups of clinical, probiotic and non-medical strains and included molecules such as trehalose, myo-inositol, lactic acid, fumaric acid and glycerol 3-phosphate. This study confirmed the link between a subset of clinical isolates and baking or probiotic strains but also highlighted that in general the clinical strains were more diverse at both the genomic and metabolic levels.

Nosocomial transmission of Saccharomyces cerevisiae in bone marrow transplant patients

Saccharomyces cerevisiae is an unusual cause of clinical infection. We describe three bone marrow transplant patients on a haematology unit who developed possible invasive disease with the organism. Two patients died and both these patients appeared to have a related strain of S. cerevisiae. Screening for S. cerevisiae from throat and stool samples revealed four further patients who were carriers. Genotyping of the invasive and carriage strains demonstrated an indistinguishable strain from patients who had been on the unit at the same time, suggesting cross-infection.