The agricultural fungicide tebuconazole is causing the pathogen Candida tropicalis to resist medical antifungals. A study found the fungicide induces chromosome changes (aneuploidy) in the fungus, which, while slowing its growth, boosts its drug resistance and virulence, creating a significant public health threat from environmental contamination.
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A study published in PLoS Biology reveals that the fungicide tebuconazole, commonly used in farming, is driving the evolution of resistance in Candida tropicalis, a fungal pathogen in India and globally.
It is a versatile yeast found in a wide range of environments. It lives in tropical and subtropical marine waters, soil, on the surface of fruits, and is also a common inhabitant of the human gut.
It primarily causes infections in people with weakened or compromised immune systems. This includes:
Types of Infections => It can cause a variety of infections, ranging from skin and gastrointestinal tract issues to severe systemic infections where it enters the bloodstream and spreads to vital organs.
High Mortality Rate => Systemic infections caused by C. tropicalis are particularly dangerous, with a high mortality rate estimated to be between 55% and 60%.
The primary treatment for C. tropicalis infections is a class of antifungal drugs known as azoles, with fluconazole and voriconazole being common examples, however, the emergence of strains that are resistant to these drugs, making infections much harder to treat.
A study published in PLoS Biology has identified a key driver behind this growing resistance.
Researchers have found that the widespread use of tebuconazole, an azole-based fungicide used in agriculture to protect crops, is promoting the evolution of drug-resistant C. tropicalis.
The study establishes a direct link between environmental practices and clinical outcomes, representing the "One Health" concept—that the health of humans, animals, and the environment are fundamentally interconnected.
The study revealed that C. tropicalis uses a rapid method to adapt and resist antifungal drugs by altering its genetic makeup.
Most complex organisms are diploid (having two sets of chromosomes). C. tropicalis was also thought to be diploid. However, when faced with the stress of an antifungal agent, it exhibits ploidy plasticity—the ability to change its chromosome number.
The resistant strains were found to be aneuploid, meaning they had an abnormal number of chromosomes. While aneuploidy is often harmful in humans, for this fungus, it is a powerful survival tool.
The genetic reshuffling makes the fungus grow slower in a normal environment but gives it a decisive survival advantage when antifungal drugs are present.
Stricter Regulation: Implementing better regulations and stewardship over the use of fungicides in agriculture.
Integrated Surveillance: Establishing surveillance systems that monitor for antifungal resistance in both environmental and clinical settings.
Developing Alternatives: Investing in the research and development of new antifungal treatments and alternative, safer crop protection strategies.
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PRACTICE QUESTION Q. In the question given below, there are two statements marked as Assertion (A) and Reason (R). Mark your answer as per the codes provided: Assertion (A): Lichens are excellent bio-indicators of air pollution. Reason (R): Lichens derive most of their mineral nutrients from atmospheric deposition. Which of the options given below is correct? A) Both A and R are true, and R is the correct explanation for A. B) Both A and R are true, but R is not the correct explanation for A. C) A is true, but R is false. D) A is false, but R is true. Answer: A Explanation: Assertion (A) is true: A bio-indicator is a living organism that gives us an idea of the health of an ecosystem. Lichens are particularly famous for their sensitivity to air quality, especially to pollutants like sulfur dioxide (SO₂), heavy metals, and nitrogen compounds. The abundance, diversity, and type of lichens growing in an area can be directly correlated with the level of air pollution. Reason (R) is true: Lichens are composite organisms (a fungus living in symbiosis with an alga or cyanobacterium). They do not have roots like plants to draw nutrients from the soil. They also lack a protective outer layer called a cuticle. Instead, their entire surface absorbs water and mineral nutrients directly from the atmosphere—that is, from rain, fog, dew, and dust particles that settle on them. This process is called atmospheric deposition. Lichens absorb everything directly from the atmosphere (as stated in R) is the reason why they are so sensitive to air pollution. |
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