Deadly human fungus Aspergillus rapidly developing drug resistance

Kathleen Blanchard's picture
Aspergillus, Aspergillosis
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Scientists are concerned about Aspergillus, a fungus that can be deadly to humans that is rapidly becoming drug treatment resistant.

Researchers from University of Manchester, working with scientists in Newark, USA, say certain strains of Aspergillus fungi are becoming resistant to anti-fungal drugs known as azoles at an “extraordinarily high rate”.

Molecular testing shows higher rates of drug resistance Aspergillus than known

The researchers used molecular testing, finding 55 percent of patients with Aspergillosis had typical “markers” showing they had developed resistance to azoles used to treat lung infection that occurs primarily in individuals with weakened immunity.

The fungus grows on leaves and trees and is sometimes found in marijuana and can pose problems from allergy, especially for individuals with asthma from worsening symptoms.

In severe cases, Aspergillosis can lead to meningitis from sinus infection, bloody sputum and endocarditis, an inflammation of the heart muscle.

David Denning, Professor of Medicine and Medical Mycology at The University of Manchester and Director of the National Aspergillosis Centre at the University Hospital of South Manchester NHS Foundation Trust explains, "Aspergillus significantly worsens asthma symptoms and causes life-threatening infections in those with long-term lung infections or damaged immune systems, such as chemotherapy and transplant patients or people with HIV.”

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The researchers discovered the rapidly growing drug resistance of the fungus by testing sputum in patients rather than waiting for typical lab cultures that are grown in a Petri dish.

They also found azole resistant Aspergillosis in patients who had never been given anti-fungal drugs, showing the widespread scope of the problem.

Denning adds, “Not only is molecular testing much more sensitive than conventional culture for diagnosis, but it enables testing for resistance, which until now has been impossible if cultures are negative. Given the rising frequency of resistance in Aspergillus in northern Europe, China and the United States, this study provides key data for doctors to shift antifungal therapy in the face of resistance."

The type of testing used by the scientists is the same as that used to diagnose HIV, MRSA and influenza that the researchers say gives a more accurate picture of the rate the fungus is becoming resistant to triazole therapy. Sputum testing showed twice as many patients had drug resistant Aspergillosis, compared to yields from Petri dish cultures.

Clin Infect Dis. 2011 May;52(9):1123-9.
“High-frequency Triazole Resistance Found In Nonculturable Aspergillus fumigatus from Lungs of Patients with Chronic Fungal Disease”
Denning DW, Park S, Lass-Florl C, Fraczek MG, Kirwan M, Gore R, Smith J, Bueid A, Moore CB, Bowyer P, Perlin DS

Image Credit: Wikimedia Commons
Author: Ninjatacoshell

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