A team of scientists from Ireland and the UK has discovered that a drug-resistant fungus could spread from the environment to patients who are susceptible.
The StudyThis week’s issue of, published in Nature MicrobiologySix patients were infected by azole-resistant strains. Aspergillus fumigatusThese strains were genetically identical to those found in soil and plants in England and Scotland, Wales, Wales, and Ireland. This suggests that they were acquired from the environment. The results also indicated that the strains may have acquired resistance to azoles through the widespread use agricultural fungicides.
“Our findings highlight new routes for resistant infections to people and provide a better understanding of how and where they are transmitted.” Aspergillus fumigatusJohanna Rhodes (PhD), lead author of the study and Imperial College London’s chief researcher, stated that drug resistance was needed. Press release.
Achieving azole resistance
Rhodes and her colleagues used whole genome sequencing (WGS), to analyze 218 A fumigatusTo gain a better understanding about the molecular epidemiology, they collected isolates from patients (153) and from the environment (65). They also performed antifungal susceptibility tests.
A fumigatusThis is an environmental fungus that is widespread and can be found in soil and vegetation. It produces spores which can be inhaled. It can cause severe lung infection in patients at high risk, such as those with cystic Fibrosis, organ transplant recipients and immunocompromised patients. Global estimates suggest that there are around 250,000 cases of invasive septicemia each year.
Over the past two decades, resistance has been steadily increasing to azoles, the first-line treatment for invasive Aspergillosis as well as one of three antifungal medications used in treating invasive fungal infections. A fumigatusWith the increase in azole resistance A fumigatusThe incidence of infections is now between 3% and 40%. A 25% increase in mortality due to resistance to azoles has been observed by day 90 compared to susceptible strains.
Extended azole therapy can lead to resistance, but resistant reactions are rare. A fumigatusIt has also been observed in patients who have not received azoles or in the environment. This has led to an increasing body of research to determine if A fumigatusThe environment is developing resistance to azoles from exposure to azole-fungicides. These fungicides are widely used in agriculture to protect fungal infections.
49% (106 isolates out of 218) were resistant at least one antifungal. 48% were resistant itraconazole, 29% to voriconazole and 21% to propaconazole. 12% were resistant two or more azole drugs.
WGS analysis revealed that the isolates were divided into two clades. Clade A (123 isolateds) contained the majority of the azoleresistant isolates and clade C (95 isolates), contained mostly azole susceptible isolates. The researchers compared resistance A fumigatusSix patients were tested for their genetic differences. Three of the six isolates, one from the environment and one from the patient, were isolated in the same city.
“Since patients are never convincingly shown that they transmit their genes,A. fumigatus“This finding is a result of the environment and shows that at-risk patients were infected in the environment by isolates that have preacquired their immunity to azoles, in the environment,” the authors wrote.
Rhodes and her colleagues also discovered previously unknown resistance mechanisms in the isolates. This finding, they claim, underscores the need to continue research into azole resistant. A fumigatus.
Matthew Fisher, PhD, study co-author, from Imperial College London, said, “Understanding environmental hotspots as well as the genetic basis for evolving fungal drug resistant is urgently needed because resistance is compromising [our] ability to prevent and treat this illness.”
