Azian Harun

Population-based surveillance for scedosporiosis in Australia: epidemiology, disease manifestations and emergence of Scedosporium aurantiacum infection.

Australia-wide population-based surveillance for scedosporiosis identified 180 cases, with 118 (65.6%) cases of colonization and 62 (34.4%) cases of infection. Predisposing factors for isolation of Scedosporium spp. included chronic lung disease in 37.8% and malignancy in 21.7% of cases. Predictors of invasive disease (n=62) included haematological stem cell transplantation (n=7), leukaemia (n=16) and diabetes mellitus (n=8). Of 183 phenotypically-speciated isolates, 75 (41%) were Scedosporium prolificans (risk factors: haematologic cancer (n=17), neutropaenia (n=14)) and 108 (59%) had Scedosporium apiospermum/Pseudallescheria boydii phenotype [risk factor: diabetes (n=15)]. Scedosporium prolificans (p 0.01) and leukaemia (p 0.03) independently predicted death. Epidemiological and antifungal susceptibility profiles of Scedosporium aurantiacum (prevalence>or=15.8%) and S. apiospermum were similar. No patient with S. aurantiacum infection (n=6) died. This is the first description of clinical features associated with S. aurantiacum.

Clinical associations and prevalence of Scedosporium spp. in Australian cystic fibrosis patients: identification of novel risk factors?

Risk factors for the association of Scedosporium in cases of cystic fibrosis (CF) and its clinical implications are poorly understood. Clinical, lung function and laboratory data of adult CF patients in Sydney (April 2008-March 2009) were prospectively analysed for such risk factors. Expectorated sputa were cultured for bacteria and examined for fungi using standard mycological and Scedosporium-selective media, and by an internal transcribed spacer region-targeted multiplex PCR assay. Scedosporium spp. (n = 4 each of Scedosporium prolificans, Scedosporium aurantiacum and Pseudallescheria boydii/ Scedosporium apiospermum complex [non-S. aurantiacum]) were recovered from 12 of 69 (17.4%) patients. Samples of 11 of the patients yielded isolates on Scedosporium- selective media (vs. 6 [8.7%] by non-selective culture) and one additional patient was noted by PCR. Of these patients, 83.3% were co-colonized with other moulds, most frequently Aspergillus fumigatus. Colonization was not associated with best FEV₁/predicted, corticosteroid or antifungal therapies. By univariate analysis, patients with Scedosporium colonization were significantly less likely to be colonized with mucoid Pseudomonas aeruginosa (P = 0.025), while prior therapy with antistaphylococcal penicillins was a risk factor for colonization (P = 0.045). Bacterial colonization and antimicrobial exposure likely influence Scedosporium colonization, which is optimally detected with selective media. Studies are required to confirm independent risk factors for Scedosporium colonization and to determine its impact on lung disease.

Molecular Typing of Australian Scedosporium Isolates Showing Genetic Variability and Numerous S. aurantiacum

Molecular typing showed genetic diversity, dismissed 2 suspected outbreaks of scedosporiosis, and identified multiple strains of the newly described species S. aurantiacum.

Abundance of Pseudallescheria/Scedosporium species in the Australian urban environment suggests a possible source for scedosporiosis including the colonization of airways in cystic fibrosis

Members of the Pseudallescheria/Scedosporium species complex are emerging opportunistic fungal pathogens which have the capacity to colonize patients with damaged airways, including those with cystic fibrosis (CF). Assuming human infection is acquired via inhalation of fungal spores from the environment, we performed a qualitative environmental survey encompassing 25 urban, semirural and rural sites in the greater Sydney region to determine the prevalence of Pseudallescheria/Scedosporium species. Soil sampling revealed an abundance of Pseudallescheria/Scedosporium, particularly in locations associated with high human activity. No variation was noted during repeated sampling at different times of the year. Strains of Scedosporium aurantiacum were most frequently isolated (54.6%), followed by Scedosporium prolificans (43%), P. boydii (2.1%) and S. dehoogii (0.3%). The findings coincide with the relatively high prevalence of Scedosporium infections in Australia and their presence as colonizers in CF patients. They emphasize the importance of environmental studies to assess the clinical risk of infection.

Genotyping of Scedosporium species: a review of molecular approaches.

Scedosporium species are increasingly encountered opportunistic fungal pathogens not only in immunocompromised patients but are also significant primary pathogens in immunocompetent individuals. The environmental reservoir of these fungi is uncertain and the epidemiology and mode of transmission are not well-defined. Conventional phenotypic methods are of limited use for epidemiological purposes since they are insensitive and inadequately discriminatory. Molecular techniques not only enable accurate phylogenetic delineation of species but also provide the means for rapid, reliable genotyping of strains for epidemiological and population genetic studies. This review discusses the methods that have been applied for genotyping of these increasingly important pathogens.

Development and validation of a multiplex PCR for detection of Scedosporium spp. in respiratory tract specimens from patients with cystic fibrosis.

ABSTRACT The emergence of Scedosporium infections in diverse groups of individuals, which are often treatment refractory, warrants timely and accurate laboratory diagnosis. Species- or group-specific primers based on internal transcribed spacer (ITS) sequence polymorphisms were designed for Scedosporium aurantiacum, Scedosporium dehoogii, Scedosporium prolificans, Pseudallescheria boydii species complex (former clade 5)/Pseudallescheria apiosperma (formerly classified as S. apiospermum sensu lato) and Pseudallescheria minutispora. Primers for S. aurantiacum, S. prolificans, and P. boydii species complex/P. apiosperma were incorporated into a multiplex PCR assay for the detection and identification of the three major clinically important Scedosporium species and validated using sputum specimens collected from patients seen at a major Australian cystic fibrosis clinic. The multiplex PCR assay showed 100% specificity in identifying the three major clinically relevant Scedosporium species from pure culture. When evaluated using DNA extracts from sputa, sensitivity and specificity of the multiplex PCR assay were 62.1% and 97.2%, respectively. This highly species-specific multiplex PCR assay offers a rapid and simple method of detection of the most clinically important Scedosporium species in respiratory tract specimens.

Fatal Mycotic Aneurysms Due to Scedosporium and Pseudallescheria Infection

ABSTRACT Angioinvasive complications of Scedosporium infections are rare. We report two cases of mycotic aneurysm, following apparent localized infection, due to Scedosporium apiospermum and Pseudallescheria boydii. The thoracoabdominal aorta was affected in one patient, and cerebral vessels were affected in the other. Despite voriconazole therapy and surgical resection, the patients died. Previously reported cases are reviewed.

Scedosporium aurantiacum is as virulent as S. prolificans, and shows strain-specific virulence differences, in a mouse model

Several Scedosporium species are clinically important emerging pathogens. Scedosporium prolificans is reported to be the most virulent of the species, while the recently described species Scedosporium aurantiacum, which accounts for a substantial proportion of Australian clinical isolates is capable of causing a range of serious infections. In addition, environmental surveys have revealed a high prevalence of S. aurantiacum in the urban Sydney region. This study was conducted to assess the virulence of selected S. aurantiacum strains recovered from patients who are colonized or have invasive disease, as well as those from environmental sources, in comparison with S. prolificans. PCR fingerprinting with the primer M13 revealed high genetic variation among the S. aurantiacum strains. We evaluated the virulence of eight S. aurantiacum and two S. prolificans strains in a murine model using an infectious dose of 2 × 10⁵ conidia. S. aurantiacum was noted to be as virulent as S. prolificans, causing death in 60-100% of mice (P > 0.05). There were significant strain-specific virulence differences (P < 0.005), indicating a possible link between genotype and virulence in S. aurantiacum.

Draft Genome of Australian Environmental Strain WM 09.24 of the Opportunistic Human Pathogen Scedosporium aurantiacum

ABSTRACT We report here the first genome assembly and annotation of the human-pathogenic fungus Scedosporium aurantiacum, with a predicted 10,525 genes, and 11,661 transcripts. The strain WM 09.24 was isolated from the environment at Circular Quay, Sydney, New South Wales, Australia.

Environmental isolation of Scedosporium species from the greater Sydney region: a link to the emergence of infections in Australia?

Scedosporium species are emerging fungal pathogens in Australia and elsewhere. The reason for this increase in infections is unclear. Since it is assumed that the infections are caused by inhalation of fungal spores, we sampled the urban and rural environment of the greater Sydney region for the presence of the human pathogenic species. Our findings indicate that there may be species-specific associations with areas of high human activity, hinting of a possible link between the environment and the emergence of infections.