Resistant yeast can cause dangerous diseases

The food industry uses drug-resistant yeasts?

A major cause of drug-resistant clinical yeast infections is the same species previously considered non-pathogenic and commonly used in the biotechnology and food industries. This is the drug-resistant yeast strain called Candida krusei.

Researchers from University College Dublin, Ireland, found in their current research that a drug-resistant yeast strain is one of the five most common causes of clinical yeast infection. The physicians published the results of their study in the English-language journal "PLOS Pathogens".

The food industry often uses a drug-resistant yeast strain that can lead to dangerous diseases. (Image: Dr_Kateryna / fotolia.com)

Yeast is responsible for increased morbidity and mortality

Candida krusei is a drug-resistant yeast strain and one of the top five causes of clinical yeast infections. This yeast strain is responsible for significantly increased morbidity and mortality in immunocompromised patients, say the experts. In contrast, another species of yeast called Pichia kudriavzevii has been classified as safe, as it has been used for centuries to produce food products such as cocoa, fermented milk and corn drinks. Also in biotechnology, this yeast plays an increasingly important role in the production of bioethanol and high-quality chemicals. So far, however, relatively few genetic or genomic studies have been performed on strains of C. krusei and P. kudriavzevii, explain the authors of the study.

Two types of yeast almost identical

In their study, scientists sequenced the genomes of 30 clinical and naturally occurring strains of these two species. The results conclusively show that they are the same species, their genomes being 99.6% identical. In addition, the two species show similar levels of resistance to antifungal agents, say the medical profession.

Industrial strains of yeast can cause disease

The results suggest that industrial strains of yeast are capable of causing disease in humans. Care should be taken when using drug-resistant P. kudriavzevii strains for biotechnology and food applications, experts suggest.

Drug resistance limits must be limited

It may be advisable to consider non-pathogenic Pichia species of yeast as possible alternatives for some industrial applications, explains study author Alexander Douglass of University College Dublin. The limit values ​​for the P. kudriavzevii strains, which are used in particular in the food industry, must be limited, the researchers say. If it were suggested that drug-resistant Candida albicans be used to make food, this plan would be rejected immediately. However, the use of Candida krusei does not disturb anyone, because food manufacturers use a different name, explains study author Professor Ken Wolfe from University College Dublin. (As)