Azole-resistant Aspergillus fumigatus found on hospital equipment

Conditions caused by Aspergillus fumigatus are becoming more prevalent across the globe. This is of particular concern to the immunocompromised, and those in intensive care unit (ICU) who are admitted for prolonged periods and treated with immunosuppressive agents.

Invasive aspergillosis caused by A. fumigatus is becoming more difficult to treat, as it becomes resistant to tradition azole medications.

Studies of this pathogen tend to focus on the outdoor environment, but a new study from Iran has highlighted the dangers of A. fumigatus in indoor settings. This is especially relevant when the setting is a hospital or healthcare facility, where there will be people with compromised immune systems.

This paper from Ghazanfari et al, shows an alarming occurrence of azole-resistant A. fumigatus within hospital equipment. Across Iran, 23 teaching hospitals participated in the study and samples were collected from the surface of medical equipment and appliances (such as computers, ventilators, anaesthesia machines, and pacemakers) in different wards (including ICU, neonatal ICU (NICU), operating room, general, and oncology wards). Azole containing agar was used for culture.

Of the 89 Aspergillus spp. isolated from almost 700 samples, 33.7%, 31.5%, 22.6%, and 12.3% were identified from ventilators, computers, anaesthesia machines, and pacemakers, respectively. A. fumigatus (41.6%) was the most frequent. Surprisingly, 19 of 37 (51.3%) showed resistance to at least one azole (itraconazole, voriconazole, or posaconazole).

All 19 isolates of voriconazole and/or itraconazole-resistant A. fumigatus showed a wide range of mutations in the CYP51A gene. The TR34/L98H mutation was present in 10 strains indicating an environmental origin of resistance. Other mutations, such as G54E, are more likely related to emergence in patients during therapy.

Aspergillus section Nigri (47.2%) was the most common group isolated, of which A. tubingensis (23.6%) was the most frequent species, followed by A. niger (15.7%). Many of these strains were cultured on voriconazole or itraconazole plates, indicative of resistance.

This work serves as a serious warning to those who are vulnerable to aspergillosis and provides insight for the administrators and managers of healthcare facilities who wish to prevent their immunocompromised patients from acquiring secondary life-threatening infections. Infection control practice may need revision, and these findings also show that environmental surveillance for resistance may require the addition of hospital environments.

Azole-resistant Aspergillus fumigatus found on hospital equipment

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