Get a (microscopic) room! Deadly fungus multiplies by mating, creating more drug-resistant strains

HAMILTON, Ontario — Candida auris is a fungus capable of causing severe infections and even death, especially among hospital patients with weakened immune systems. Even worse, many strains of C. auris are antibiotic-resistant “superbugs.” Now, scientists from McMaster University report the fungus can reproduce by having sex.

Study authors clarify that while C. auris sex doesn’t happen all that often, when it does occur it may be producing more drug-resistant, more virulent, and faster spreading strains of Candida auris.

Generally speaking, microorganisms like C. auris usually divide and reproduce asexually. One produces two, two create four, and on and on. All of those “births” are genetically identical to each other. This occurs via a “process of very simple division and without the exchange of genetic material.”

“One of the really complex and puzzling questions about this fungal pathogen is its origin and how it reproduces in nature,” says Jianping Xu, a professor in McMaster’s Department of Biology and researcher with Canada’s Global Nexus for Pandemics and Biological Threats, in a university release.

Researchers analyzed close to 1,300 strains of C. auris for this project, all provided by a public database of C. auris genome sequences. More specifically, the research team searched for and confirmed “recombination events” (sex).

The fungus is spreading and is even in food!

Moving forward, this work will greatly assist further relevant research. Scientists can now replicate these sexual behaviors in a lab setting.

“The research tells us that this fungus has recombined in the past and can recombine in nature, which enable it to generate new genetic variants rather quickly,” Prof. Xu explains. “That may sound frightening, but it’s a double-edged sword. Because we learned they could recombine in nature, we could possibly replicate the process in the lab, which could allow us to understand the genetic controls of virulence and drug resistance and potentially other traits that make it such a dangerous pathogen, much faster.”

First discovered in 2009, C. auris has since spread to over 50 countries. Thousands have died due to infections. In Canada alone, there are five known divergent lineages of C. auris, with some being found in the same medical facilities.

Prof. Xu explains that if one drug-resistant strain “mixes” with another strain that is resistant to a different drug, the resulting offspring could conceivably be resistant to both drugs.

“The mixing of strains in the same hospital, potentially in the same patient, creates an opportunity for them to meet and mate,” he concludes. “This study is about sex and the implication of sex to organisms is often very broad. For fungi, it means they can spread genes that are beneficial to them much faster through populations than asexual reproduction alone.”

C. auris isn’t just in hospitals. Previous work conducted by Prof. Xu has discovered drug-resistant strains of C. auris on the skins of two popular apples: Royal Gala and Red Delicious. The apples had been treated with fungicides to produce a longer shelf life.

The study is published in Computational and Structural Biotechnology Journal.

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