Mycology and Antifungals Overview

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Questions and Answers

What is a notable characteristic of Candida auris clades observed between them?

They all share the same genetic ancestor.

They show a high level of genetic diversity with 40,000 to 200,000 SNPs. (correct)

They have relatedness with less than 600 SNPs intra-clade. (correct)

They are identical with no variation across the globe.

Which environmental factor is most likely contributing to the rise of Candida auris?

Increased levels of humidity.

Decreased use of antifungal treatments.

Global warming enabling tolerance to higher temperatures. (correct)

Reduction in plastic pollution.

What ecological characteristic aids Candida auris in its environment?

Ability to thrive in low-salt environments.

Resistance to high levels of NaCl up to 10%. (correct)

Dependency on freshwater sources.

Vulnerability to antibiotic treatments.

What hypothesis explains the rapid global spread of Candida auris clades?

Multiple strains evolved simultaneously in different locations. Signup and view all the answers

What is one of the main challenges in studying the reservoir for Candida auris?

The intermediate animal reservoir has not yet been established. Signup and view all the answers

What recent emergence has been noted in relation to fungal pathogens?

Trichophyton indotineae as a multidrug-resistant dermatophyte. Signup and view all the answers

What is the primary action of azoles in relation to fungal infections?

They inhibit ergosterol synthesis. Signup and view all the answers

What is a significant consequence of biofilm formation in fungi?

Formation of resistant strains. Signup and view all the answers

What groups of compounds do azoles belong to?

Imidazole and triazole. Signup and view all the answers

What is the maximal recommended dosage of a certain drug mentioned?

1mg/kg/day. Signup and view all the answers

How much can biofilms increase drug resistance in fungi?

1000 fold. Signup and view all the answers

What is a major contributor to the development of resistance to azoles?

Agricultural use of azoles. Signup and view all the answers

What is the role of azoles against yeast infections?

They are generally fungistatic. Signup and view all the answers

What percentage of environmental Aspergillus strains in the UK are resistant to medical azoles?

14% Signup and view all the answers

Which component of fungi is primarily targeted by echinocandins?

Chitin Signup and view all the answers

What is the main therapeutic action of polyenes?

Binding to Ergosterol Signup and view all the answers

What distinguishes echinocandins from other antifungal drugs?

They target the cell wall Signup and view all the answers

What is a notable characteristic of Amphotericin B?

It exhibits broad spectrum activity Signup and view all the answers

What type of infections do echinocandins primarily treat?

Yeast invasive infections Signup and view all the answers

What is the role of ergosterol in fungal cells?

Ensuring plasma membrane fluidity Signup and view all the answers

What is the main mechanism of action for Echinocandins?

Inhibition of β-glucans Signup and view all the answers

What potential issue is associated with the drug Ipflufenoquin?

It causes increased resistance in fungi Signup and view all the answers

Which antifungal drug class was introduced first?

Polyenes Signup and view all the answers

What is a significant concern regarding antifungal drugs?

Resistance is on the rise Signup and view all the answers

Which temperature is currently noted as optimal for only 6% of fungi?

37°C Signup and view all the answers

How do Azoles primarily function in combating fungal infections?

By inhibiting ergosterol synthesis Signup and view all the answers

What has been reported about Candida auris as of 2022?

It has a high rate of pan-resistance Signup and view all the answers

Why is an increase in immunosuppressed individuals a concern regarding fungal infections?

They have a higher risk of developing fungal infections Signup and view all the answers

What type of pathogens are highlighted as a priority concern?

Fungal pathogens Signup and view all the answers

What characteristic of the current fungal landscape raises concerns for the future?

New conditions are promoting fungal dispersion Signup and view all the answers

Study Notes

Mycology in a Warming World

Mycology is the study of fungi
Approximately 35,000 Canadians suffer from cardiac arrest each year
CPR can triple the odds of survival
Survival rates are greater than 50% if defibrillated within the first 5 minutes. Early recognition, calling 911, chest compressions, and using an AED are key elements of the Chain of Survival.

Antifungals

Antifungals are crucial for treating fungal infections, but developing resistance to them is a growing concern.
Finding effective antifungal targets is challenging, as fungi, unlike animals, contain ergosterol in their cell membranes
Three main families of developed antifungals target ergosterol or the fungal cell wall.

Target 1: Fungal Cell Wall

Fungal cell walls are made of complex polysaccharides, primarily chitin.
There are limited approved drugs targeting the fungal cell wall.

Target 2: Ergosterol

Ergosterol is a crucial component of fungal cell membranes, maintaining fluidity and structure.
Two significant antifungal families, polyenes and azoles, target ergosterol; polyenes bind to ergosterol and disrupt the fungal membrane, while azoles inhibit ergosterol synthesis, preventing membrane formation.

Antifungal Summary

Three major groups of antifungal drugs are:
- Echinocandins (2001) targeting β-glucans.
- Polyenes (1950s) targeting ergosterol.
- Azoles (1960s) inhibiting ergosterol synthesis.
Resistance to antifungals is increasing, posing a challenge for treatment.
Mechanisms of resistance include biofilm formation, loss of mitochondrial function, mutations in cell wall biosynthesis genes, increased drug efflux, stress signaling, inhibited pyrimidine salvage pathways, upregulation/mutations in target genes, and lipid metabolism.

Important Limitations

Azoles have a significant rate of resistance development, partly due to agricultural use.
This has direct consequences for medical treatments, with certain fungal strains showing high resistance to multiple azoles.

Unexpected Pathogens

New and unexpected pathogens are emerging.
One example is Chondrostereum purpureum, a fungal infection that is causing paratracheal abscesses.
Another is Megasporoporia setulosa resulting in subcutaneous mycosis.

Valley Fever

Coccidioidomycosis (Valley fever) is a fungal infection caused by Coccidioides immitis and other related Coccidioides species.
It's a significant concern, particularly in the western United States due to climate changes that lead to higher-than-usual temperatures, and lower than usual humidity.
A growing epidemic, it typically involves pulmonary infections, but can disseminate to other parts of the body.

Conclusions

Humans are not fully prepared for fungal pandemics.
Environmental changes, fungal resistance, and emerging pathogens require increased attention and research efforts by healthcare specialists and researchers.

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Description

Explore the vital aspects of mycology in the context of a warming world and the challenges posed by antifungal resistance. Learn about the structure of fungal cells, including the cell wall and ergosterol, as well as treatment strategies for fungal infections. This quiz will deepen your understanding of fungal biology and therapeutic approaches.