Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, CA 92521, USA.
Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
G3 (Bethesda). 2022 May 6;12(5). doi: 10.1093/g3journal/jkac075.
Birds are highly susceptible to aspergillosis, which can manifest as a primary infection in both domestic and wild birds. Aspergillosis in wild birds causes mortalities ranging in scale from single animals to large-scale epizootic events. However, pathogenicity factors associated with aspergillosis in wild birds have not been examined. Specifically, it is unknown whether wild bird-infecting strains are host-adapted (i.e. phylogenetically related). Similarly, it is unknown whether epizootics are driven by contact with clonal strains that possess unique pathogenic or virulence properties, or by distinct and equally pathogenic strains. Here, we use a diverse collection of Aspergillus fumigatus isolates taken from aspergillosis-associated avian carcasses, representing 24 bird species from a wide geographic range, and representing individual bird mortalities as well as epizootic events. These isolates were sequenced and analyzed along with 130 phylogenetically diverse human clinical isolates to investigate the genetic diversity and phylogenetic placement of avian-associated A. fumigatus, the geographic and host distribution of avian isolates, evidence for clonal outbreaks among wild birds, and the frequency of azole resistance in avian isolates. We found that avian isolates were phylogenetically diverse, with no clear distinction from human clinical isolates, and no sign of host or geographic specificity. Avian isolates from the same epizootic events were diverse and phylogenetically distant, suggesting that avian aspergillosis is not contagious among wild birds and that outbreaks are likely driven by environmental spore loads or host comorbidities. Finally, all avian isolates were susceptible to Voriconazole and none contained the canonical azole resistance gene variants.
鸟类极易感染曲霉菌病，无论是家养鸟还是野生鸟都可能发生原发性感染。野生鸟类感染曲霉菌病可导致从单个动物到大规模流行的死亡，规模不等。然而，尚未研究与野生鸟类曲霉菌病相关的致病性因素。具体来说，尚不清楚野生鸟类感染的菌株是否具有宿主适应性（即系统发育上相关）。同样，也不知道流行是否是由具有独特致病性或毒力特性的克隆株引起，还是由不同但同样具有致病性的菌株引起。在这里，我们使用了从与曲霉菌病相关的禽类尸体中采集的各种烟曲霉分离株，这些分离株代表了来自广泛地理范围的 24 种鸟类，代表了单个鸟类的死亡以及流行事件。我们对这些分离株进行了测序和分析，并与 130 种具有系统发育多样性的人类临床分离株一起分析，以研究与禽类相关的烟曲霉的遗传多样性和系统发育位置、禽类分离株的地理和宿主分布、野生鸟类中克隆暴发的证据，以及禽类分离株中唑类药物耐药的频率。我们发现，禽类分离株具有遗传多样性，与人类临床分离株没有明显区别，也没有宿主或地理特异性的迹象。来自同一流行事件的禽类分离株具有多样性和系统发育上的差异，这表明野生鸟类之间的禽曲霉菌病不具有传染性，爆发可能是由环境孢子负荷或宿主合并症引起的。最后，所有禽类分离株对伏立康唑均敏感，且均不含经典唑类耐药基因变异。
