Pulmonary Aspergillosis in Humboldt Penguins—Susceptibility Patterns and Molecular Epidemiology of Clinical and Environmental Aspergillus fumigatus Isolates from a Belgian Zoo, 2017–2022

Abstract

Aspergillus fumigatus is the main causative agent of avian aspergillosis and results in significant health problems in birds, especially those living in captivity. The fungal contamination by A. fumigatus in the environment of Humboldt penguins (Spheniscus humboldti), located in a Belgian zoo, was assessed through the analysis of air, water, sand and nest samples during four non-consecutive days in 2021–2022. From these samples, potential azole-resistant A. fumigatus (ARAF) isolates were detected using a selective culture medium. A total of 28 veterinary isolates obtained after necropsy of Humboldt penguins and other avian species from the zoo were also included. All veterinary and suspected ARAF isolates from the environment were characterized for their azole-resistance profile by broth microdilution. Isolates displaying phenotypic resistance against at least one medical azole were systematically screened for mutations in the cyp51A gene. A total of 14 (13.6%) ARAF isolates were identified from the environment (n = 8) and from Humboldt penguins (n = 6). The TR34/L98H mutation was observed in all resistant environmental strains, and in two resistant veterinary strains. To the best of our knowledge, this is the first description of this mutation in A. fumigatus isolates from Humboldt penguins. During the period 2017–2022, pulmonary aspergillosis was confirmed in 51 necropsied penguins, which reflects a death rate due to aspergillosis of 68.0%, mostly affecting adults. Microsatellite polymorphism analysis revealed a high level of diversity among environmental and veterinary A. fumigatus isolates. However, a cluster was observed between one veterinary isolate and six environmental strains, all resistant to medical azoles. In conclusion, the environment of the Humboldt penguins is a potential contamination source of ARAF, making their management even more complex.

Emerging Antifungal Resistance in Fungal Pathogens

“…Despite not being drug-resistant, the outbreak still resulted in 21 infections and 9 deaths, in a population of only 211. A known opportunistic pathogen of penguins [ 25 ], azole drug-resistant A. fumigatus has been isolated from a zoo environment and from Humboldt penguins themselves [ 26 ]. However, little research is dedicated to the impact of aspergillosis on wildlife species in terms of clinical outcome and treatment failure, certainly highlighting a gap in our current knowledge.…”

Catching more air: A method to spatially quantify aerial triazole resistance inAspergillus fumigatus

“…Due to their small size and hydrophobic nature, these spores readily disperse through the air when plant waste heaps are disturbed [5, 6]. The plant waste heaps are considered the optimal habitat for A. fumigatus , while this fungus also is an opportunistic pathogen that can infect or colonise the lungs of birds, humans and other mammals [7, 1, 8]. Humans are believed to inhale roughly 100 spores per day on average [9, 1], and although the immune systems of most humans efficiently remove these spores, they can cause symptoms ranging from mild allergies to often-lethal acute invasive aspergillosis infections, depending on the health status of an individual’s lungs and their immune system status [10, 1].…”