Isolation of Fungi, Especially <i>Exophiala dermatitidis</i>, in Patients Suffering from Cystic Fibrosis

Abstract

Background: Patients with cystic fibrosis (CF) are at an increased risk of pulmonary colonisation by opportunistic micro-organisms. Using specialised methods, the black yeast Exophiala dermatitidis could consistently be cultured from CF patients. Isolation rates from sputum samples ranged between 1.8 and 15.7%. Occasionally, infection could be recognised. Objectives: This study aimed at investigating the isolation rates of E. dermatitidis in samples taken from CF patients at the University of Bonn, Germany. Methods: Altogether, 439 respiratory specimens taken from 81 CF patients were screened for the occurrence of E. dermatitidis over a period of 18 months. For the selective isolation of this fungus erythritol-chloramphenicol agar (ECA) produced in house was applied. Results: The isolation rate of E. dermatitidis was 1.1% from all specimens, 1.6% from all sputum samples and 6.2% in all patients examined. Conclusions: Prior to the introduction of ECA, E. dermatitidis had never been isolated in our laboratory, either from CF, or from any other patient. During this study, E. dermatitidis was found to colonise the respiratory tract of some CF patients. The use of additional selective culture media is necessary for the recognition of uncommon fungi, e.g. E. dermatitidis, in CF patients.

Spectrum of Clinically RelevantExophialaSpecies in the United States

“…The most frequent deep infections are those of the respiratory system caused by E. dermatitidis, E. oligosperma, E. phaeomuriformis, and E. lecanii-corni. Pulmonary infections are mostly not invasive, but probably subclinical colonization is involved, as observed in patients with cystic fibrosis (18,24). In Europe, this is one of the preponderant clinical pictures by Exophiala species, particularly E. dermatitidis (18,24).…”

“…Pulmonary infections are mostly not invasive, but probably subclinical colonization is involved, as observed in patients with cystic fibrosis (18,24). In Europe, this is one of the preponderant clinical pictures by Exophiala species, particularly E. dermatitidis (18,24). This fungus occurs with a frequency of 2 to 8% in the susceptible patient population (21); similar screening has thus far not been done in the United States.…”

“…At least 11 fatal cases were reported (6,23,26). Primary cerebral infection caused by E. dermatitidis appears to occur nearly only in Asian patients, the possibility of race-dependent virulence has been suggested (24). Strains of E. spinifera were mainly involved in cutaneous and subcutaneous mycoses.…”

High Rate of Exophiala dermatitidis Recovery in the Airways of Patients with Cystic Fibrosis Is Associated with Pancreatic Insufficiency

“…Processed sputum and BAL fluid specimens (20 l) were plated onto horse blood agar, streptococcus agar, haemophilus agar, Sabouraud agar, and erythritol chloramphenicol agar (ECA) (13). The last two media are selective for the isolation of E. dermatitidis, while the others were used to determine bacterial cocolonization.…”

The development of the approaches for fungal pathogens identification directly in respiratory samples of cystic fibrosis patients

“…Раз-витие систематики грибов также влияло на расши-рение спектра выявляемых возбудителей микозов. Например, для эуротиомицета Exophiala dermatitidis со сложной таксономической судьбой было уста-новлено, что им инфицировано от 6,2% [22] до 9% [23] пациентов c МВ в Германии. Наконец, внедре-ние процедуры трансплантации легких для больных МВ также увеличило возможность инфицирования пациентов представителями царства Fungi.…”