Airborne Aspergillus fumigatus conidia: a risk factor for aspergillosis

O’Gorman, Céline M.

doi:10.1016/j.fbr.2011.07.002

Cited by 67 publications

(54 citation statements)

References 63 publications

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“…The ascospores were heat resistant (57), capable of surviving at 80°C for at least 30 min, as is typical for other members of the genus Neosartorya (56). This might reflect selection in a common ancestor of Neosartorya for survival in ecological niches where high temperatures might be encountered, such as composting vegetation (58). Ascospore progeny from a cross between isolates 78-2 and 78-3 were then assessed for evidence of recombination.…”

Section: Resultsmentioning

confidence: 99%

Discovery of a Sexual Cycle in Aspergillus lentulus, a Close Relative of A. fumigatus

et al. 2013

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Aspergillus lentulus was described in 2005 as a new species within the A. fumigatus sensu lato complex. It is an opportunistic human pathogen causing invasive aspergillosis with high mortality rates, and it has been isolated from clinical and environmental sources. The species is morphologically nearly identical to A. fumigatus sensu stricto, and this similarity has resulted in their frequent misidentification. Comparative studies show that A. lentulus has some distinguishing growth features and decreased in vitro susceptibility to several antifungal agents, including amphotericin B and caspofungin. Similar to the once-presumed-asexual A. fumigatus, it has only been known to reproduce mitotically. However, we now show that A. lentulus has a heterothallic sexual breeding system. A PCR-based mating-type diagnostic detected isolates of either the MAT1-1 or MAT1-2 genotype, and examination of 26 worldwide clinical and environmental isolates revealed similar ratios of the two mating types (38% versus 62%, respectively). MAT1-1 and MAT1-2 idiomorph regions were analyzed, revealing the presence of characteristic alpha and high-mobility-group (HMG) domain genes, together with other more unusual features such as a MAT1-2-4 gene. We then demonstrated that A. lentulus possesses a functional sexual cycle with mature cleistothecia, containing heat-resistant ascospores, being produced after 3 weeks of incubation. Recombination was confirmed using molecular markers. However, isolates of A. lentulus failed to cross with highly fertile strains of A. fumigatus, demonstrating reproductive isolation between these sibling species. The discovery of the A. lentulus sexual stage has significant implications for the management of drug resistance and control of invasive aspergillosis associated with this emerging fungal pathogen.

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Section: Resultsmentioning

confidence: 99%

Discovery of a Sexual Cycle in Aspergillus lentulus, a Close Relative of A. fumigatus

et al. 2013

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“…This dominance of A. fumigatus is likely due to ecological traits, such as the high prevalence and buoyancy of its spores in the environment [85], as well as genetic ones, such as the ability to grow well at 37°C and the coating of its spores with a hydrophobin that renders them immunologically inert [86]. In the aftermath of the decoding of the A. fumigatus genome and its close relatives [17, 18], a number of studies have greatly increased our understanding of its genetic makeup and how it interacts with the human host to produce a wide range of aspergillosis diseases.…”

Section: The Inner Workings Of a Pathogenmentioning

confidence: 99%

The function and evolution of the Aspergillus genome

Gibbons

Rokas

2013

Trends in Microbiology

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Species in the filamentous fungal genus Aspergillus display a wide diversity of lifestyles and are of great importance to humans. The decoding of genome sequences from a dozen species that vary widely in their degree of evolutionary affinity has galvanized studies of the function and evolution of the Aspergillus genome in clinical, industrial, and agricultural environments. Here, we synthesize recent key findings that shed light on the architecture of the Aspergillus genome, on the molecular foundations of the genus’ astounding dexterity and diversity in secondary metabolism, and on the genetic underpinnings of virulence in Aspergillus fumigatus, one of the most lethal fungal pathogens. Many of these insights dramatically expand our knowledge of fungal and microbial eukaryote genome evolution and function and argue that Aspergillus constitutes a superb model clade for the study of functional and comparative genomics.

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“…The principal route of infection is through the inhalation of airborne spores, which due to their small spore size are able to reach the alveoli (Dagenais & Keller, 2009;Ibrahim-Granet et al, 2003;Latgé, 1999;O'Gorman, 2011;Philippe et al, 2003). While other aspergilli can cause opportunistic infections (such as Aspergillus terreus and Aspergillus flavus), A. fumigatus accounts for~90 % of all cases despite airborne spore numbers only accounting for ,1 % of all Aspergillus spores (Rementeria et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus

Alshareef

Robson

2014

Microbiology

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Environmental populations of the opportunistic pathogen Aspergillus fumigatus have been shown to be genotypically diverse and to contain a range of isolates with varying pathogenic potential. In this study, we combined two RAPD primers to investigate the genetic diversity of environmental isolates from Manchester collected monthly over 1 year alongside Dublin environmental isolates and clinical isolates from patients. RAPD analysis revealed a diverse genotype, but with three major clinical isolate clusters. When the pathogenicity of clinical and Dublin isolates was compared with a random selection of Manchester isolates in a Galleria mellonella larvae model, as a group, clinical isolates were significantly more pathogenic than environmental isolates. Moreover, when relative pathogenicity of individual isolates was compared, clinical isolates were the most pathogenic, Dublin isolates were the least pathogenic and Manchester isolates showed a range in pathogenicity. Overall, this suggests that the environmental population is genetically diverse, displaying a range in pathogenicity, and that the most pathogenic strains from the environment are selected during patient infection. INTRODUCTIONAspergillus fumigatus is an opportunistic fungal pathogen that can cause aspergillosis in immunocompromised patients, such as those with neutropenia or on immunosuppressive therapy following solid organ transplantation (Abad et al., 2010;Ben-Ami et al., 2010;Dagenais & Keller, 2009;Latgé, 1999;Rementeria et al., 2005). The principal route of infection is through the inhalation of airborne spores, which due to their small spore size are able to reach the alveoli (Dagenais & Keller, 2009;Ibrahim-Granet et al., 2003;Latgé, 1999;O'Gorman, 2011;Philippe et al., 2003). While other aspergilli can cause opportunistic infections (such as Aspergillus terreus and Aspergillus flavus), A. fumigatus accounts for~90 % of all cases despite airborne spore numbers only accounting for ,1 % of all Aspergillus spores (Rementeria et al., 2005). A number of studies have shown a high degree of genetic variation within the A. fumigatus population, and whilst some studies have indicated potential geographical subgroups, comparisons between clinical isolates and environmental isolates have largely been unable to distinguish these populations (Araujo et al., 2010;Aufauvre-Brown et al., 1992;Balajee et al., 2008;Chazalet et al., 1998;Denning et al., 1990;Duarte-Escalante et al., 2009; Leenders et al., 1999;Menotti et al., 2005). Moreover, epidemiological studies have largely failed to match genotypes in infected patients with genotypes found in hospitals, in part due to the high level of genetic diversity in the environmental populations (Araujo et al., 2010;Bart-Delabesse et al., 1999;Chazalet et al., 1998;Guinea et al., 2011; Leenders et al., 1999;de Valk et al., 2007), and similar findings have been reported in avian populations (Arné et al., 2011;Lair-Fulleringer et al., 2003;Olias et al., 2011). Whilst genotyping of isolates from some individual patient...

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Airborne Aspergillus fumigatus conidia: a risk factor for aspergillosis

Cited by 67 publications

References 63 publications

Discovery of a Sexual Cycle in Aspergillus lentulus, a Close Relative of A. fumigatus

Discovery of a Sexual Cycle in Aspergillus lentulus, a Close Relative of A. fumigatus

The function and evolution of the Aspergillus genome

Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus

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