Exophiala (Wangiella) dermatitidis and cystic fibrosis – Prevalence and risk factors

Abstract

The objective of this prospective study was to assess the prevalence of Exophiala dermatitidis in respiratory secretions of patients with cystic fibrosis (CF) and to identify risk factors for its presence. The results of all cultures performed over a 2-year period in non lung-transplant patients in our CF clinic were included in the study. Samples consisted of sputum (whenever possible) or deep pharyngeal aspirate after a session of physiotherapy. Specimens were inoculated onto Sabouraud gentamicin-chloramphenicol agar (SGCA) medium (Becton-Dickinson) and incubated at 35°C for 2 days and then at ambient temperature (15-25°C) for 3 weeks. The whole study group included 154 patients (mean age ± SD: 18.5 y ± 11.69). E. dermatitidis was isolated from 58 specimens (2.8%) of nine patients (5.8%) out of total of 2065 cultures prepared during the study period. All E. dermatitidis culture-positive patients were pancreatic insufficient and ≥12 y of age. Almost all (8/9) were homozygous for the F508 del mutation. Aspergillus fumigatus colonization and genotype seemed to be predisposing factors. No other significant characteristic was identified in this group, either in terms of predominant bacterial pathogen or treatment. A distinct comparative study performed over 3 months in our laboratory revealed that the use of SGCA yielded identical isolation rates of E. dermatitidis as erythritol-chloramphenicol agar (ECA).

Molecular typing and antifungal susceptibility of Exophiala isolates from patients with cystic fibrosis

“…Rare nosocomial outbreaks with fatal neurological involvement have been reported in patients due to the use of medical fluids containing contaminated water (Woollons et al, 1996;CDC, 2002) But more often, the fungus is recovered from the respiratory tract of patients with cystic fibrosis (CF) (Haase et al, 1991;Horré et al, 2004). In these patients, who are prone to colonization by filamentous fungi (Pihet et al, 2009), E. dermatitidis may cause chronic colonization of the airways (Blaschke-Hellmessen et al, 1994;Diemert et al, 2001;Haase et al, 1991;Horré et al, 2004;Kusenbach et al, 1992;Lebecque et al, 2010).…”

Glivne okužbe pri bolnikih s cistično fibrozo

“…Most research indicates that E. dermatitidis has the role of a coloniser in CF and that the isolation from the respiratory tract normally does not indicate an infection. At the moment, the identified risk factors for the colonisation with E. dermatitidis are the age above 12, pancreatic insufficiency and the colonisation with A. fumigatus (40,43). It is interesting that the occurrence of E. dermatitidis drops after the age of 35 (41).…”

“…It is interesting that the occurrence of E. dermatitidis drops after the age of 35 (41). The colonisation is supposedly also dependent on the patient's genotype: it was most common in patients with a mutation of the CFTR gene at position 508 on chromosome 7 (genotype ∆F508/∆F508) (40). It is mostly a chronic colonisation, which can be established only after an extended incubation period on classic and/or specific mycological media with the addition of erythritol and chloramphenicol (40).…”

“…In Europe, E. dermatitidis is isolated from 5 to 19 % of respiratory samples; descriptions of supposed invasive infections are rare (38)(39)(40)(41). None of the documented cases meet the criteria for a confirmed invasive mycosis -the described diagnoses are usually based on the isolation of E. dermatitidis from the sputum.…”

“…The colonisation is supposedly also dependent on the patient's genotype: it was most common in patients with a mutation of the CFTR gene at position 508 on chromosome 7 (genotype ∆F508/∆F508) (40). It is mostly a chronic colonisation, which can be established only after an extended incubation period on classic and/or specific mycological media with the addition of erythritol and chloramphenicol (40). For the isolation of E. dermatitidis, clinical samples have to be incubated for 5 to 7 days on average (43).…”