Focus on fungi: understanding Candida albicans

18 March 2018
​At the VIB-KU Leuven Center for Microbiology, Patrick Van Dijck and his team study a peculiar type of fungus: Candida albicans. This organism is the cause of several common ailments, like white tongue and vaginal infections. Alarmingly, under specific circumstances, the fungus also becomes a vicious killer.

Patrick: “For most of us, C. albicans is a common fungus in our gut. If introduced into the bloodstream of patients with a weakened immune system, it can turn into a deadly pathogen, killing 40 to 60% of them. We seek to understand the virulence factors of the fungus to develop therapeutic strategies.”

The implants issue
One of those virulence factors is the formation of biofilms: natural protective layers that communities of cells create to protect themselves against adverse environmental factors. These biofilms shelter C. albicans from the patient’s immune system and from specific antifungal drugs. Patrick: “Implants, such as catheters or hip
replacements, are ideal substrates for C. albicans to attach to and form biofilms. As more patients get
implants, this becomes a big problem.”

“Today, when a biofilm is formed, the only solution we have is to replace the implant. For a simple catheter, that’s doable, but for other implants, such as heart valves, the consequences are much bigger.” Over the last few years, Patrick and his team have become leading experts in the study of these films. They have developed an in vivo rodent model system that allows them to investigate the effects of biofilms on the immune system and to test anti-biofilm drugs.

Antifungal drug resistance
Another issue tackled in the lab is antifungal drug resistance. Patrick: “When patients don’t react to a drug, they are given a higher dose. But C. albicans responds by developing new resistance mechanisms, which leads to a vicious circle until the dose can’t be upped anymore, and the patient dies from the fungal infection.”

The team is close to understanding the reason for C. albicans’ tolerance to the most widely used antifungal drug, fluconazole. “Unraveling the molecular mechanisms behind this tolerance allows us to screen for novel compounds that would, together with fluconazole, result in a fungicidal combination.”

More than fungi
Instead of merely focusing on fungi, the team is also looking into the molecular interaction between bacteria and fungi. “Scientists tend to study one or the other,” Patrick says. “But that doesn’t make sense, since bacteria and fungi live together in the human body. Multiple mutual effects are at play between the two, which impacts the influence of these organisms on the patient. I strongly believe that to truly advance in science, we need to bring both worlds together.”

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Patrick Van Dijck