Selective Isolation of <i>Pseudallescheria</i> and <i>Scedosporium </i>Species from Respiratory Tract Specimens of Cystic Fibrosis Patients

Abstract

Background: Fungi of the Pseudallescheria/Scedosporium complex are known to be colonizers and infectious agents of the respiratory tract of cystic fibrosis (CF) patients. Colonized CF patients are at high risk for the development of disseminated scedosporiosis after lung transplantation. The detection of these fungi may be difficult, because they grow slowly and so will be overgrown by faster-developing microorganisms on the media routinely used in diagnostic laboratories. Objectives: To examine the usefulness of the isolation medium SceSel+ agar as a diagnostic tool for clinical samples from CF patients. Methods: 150 respiratory tract samples from 42 CF patients were inoculated on SceSel+ agar. During the incubation phase, which lasted up to 30 days at 36 ± 1°C, the cultures were inspected every 2 or 3 days. Results: The isolation of Scedosporium species was successful in 3 samples (2%) with standard microbiological media and procedures, while the isolation rate on SceSel+ agar was 5.3% (8 of 150 specimens). Conclusions: Our results suggest that standard microbiological media and procedures are not sufficient to detect colonization of the respiratory tract by Pseudallescheria/Scedosporium in CF patients. By use of SceSel+ agar, fungi belonging to this complex were isolated more frequently. Therefore, this semiselective mycological isolation medium should be used for the detection of these fungi in the respiratory tract of CF patients, especially in patients in whom a fungal infection is assumed or who are scheduled for lung transplantation.

Purification and Characterization of a Mycelial Catalase from Scedosporium boydii, a Useful Tool for Specific Antibody Detection in Patients with Cystic Fibrosis

“…However, these fungi have gained attention during the past 2 decades mainly because of their recognition as common agents of colonization of the airways in patients with cystic fibrosis (CF). When appropriate culture media are used, the S. apiospermum species complex ranks second among the filamentous fungi recovered from respiratory specimens, with a prevalence ranging from 4.5 to 11.6% in patients (8)(9)(10)(11)(12). Although usually asymptomatic, this fungal colonization of the airways may sometimes lead to allergic bronchopulmonary mycoses, sensitization, or respiratory infections (8,13).…”

Isolation of Scedosporium apiospermum (Teleomorph: Pseudallescheria apiosperma) from an Acute Myeloid Leukemia Patient

“…Rutin olarak kullanı-lan mikolojik besiyerlerinde Aspergillus ve Candida türlerinin üremesi sonucunda S.apiospermum varlığı gözden kaçmaktadır. Farklı immünsüpresif hasta gruplarında serolojik ve moleküler yöntemlerle alınan sonuçlar, bu mantarın, kültürle alınan sonuçlardan daha yüksek oranda bulunabileceğini göstermektedir 2,3 . Bu durum skedosporyozun gözden kaçan bir enfeksiyon olduğunu düşündürmektedir.…”

A Multi-Faceted Diagnostic Approach to Lung Infections in Patients with Cystic Fibrosis

“…Some fungi, such as Scediosporim and Pseudallescheria are difficult to identify with these methods (Horré et al, 2009;Williamson et al, 2001). In those cases, molecular analysis using fungal ribosomal rRNA genes and the associated internal spacer regions (ITS) are employed (Bouchara et al, 2009;Hinrikson et al, 2005;Kumeda & Asao, 1996;Schmidt & Rath, 2003;Williamson et al, 2001;Zeng et al, 2007b).…”

“…Species-specific PCR and culturing have identified a few fungi, such as Aspergillus and Candida (Bakare et al, 2003;Cimon et al, 2001;Mearns et al, 1967). There have been reports of Scedosporium apiospermum, Exophilia sp., and Wangiella dermatitidis being cultured from CF sputa (Defontaine et al, 2002;Dixon & Polak-Wyss, 1991;Hennequin et al, 1997;Horré et al, 2004;Horré et al, 2009;Rogers et al, 2003;Williamson et al, 2001). Recent statistics have shown that there is an increase in the prevalence of fungi being detected in the CF patient which may be a consequence of aggressive antibacterial therapy (Nagano et al, 2007).…”