A prospective survey of Aspergillus spp. in respiratory tract samples: prevalence, clinical impact and antifungal susceptibility

Abstract

A three-month laboratory-based prospective survey was conducted at four major university hospitals covering one-third of the Danish population in order to determine the prevalence, significance, and susceptibility pattern of aspergilli in airway samples. Samples received in January-March 2007 for routine microbiologic investigation were examined for Aspergillus following routine procedures and with extended incubation (5 days). Identification was done by morphologic criteria and susceptibility testing using EUCAST method for azoles and amphotericin B E-test. Invasive aspergillosis (IA) was evaluated using modified EORTC/MSG criteria. A total of 11,368 airway samples were received. Growth of Aspergillus spp. was found in 129 and 151 patients using routine and extended incubation, respectively. Three patients had proven IA (2%), 11 probable (7%), four had allergic bronchopulmonary aspergillosis (ABPA) (3%), but the majority was colonised (88%). Underlying conditions were cystic fibrosis in 82 patients (55%), chronic obstructive pulmonary disease in 19 (13%) and haematological disorder in 11 (7%). Twenty-six patients (18%) were at intensive care unit and 69 (47%) received steroid treatment. Azole MICs were elevated for five isolates as follows (itraconazole, posaconazole, voriconazole MICs [mg/L]): two A. fumigatus isolates (>4; >4; 2 and >4; 0.125; 1), one A. lentulus isolate (2; 2; 0.5) and two A. terreus isolates (2; 2; 2 and 2; 0.125; 1). For four isolates the amphotericin B MIC was >1 μg/ml (3/112 A. fumigatus, 1/2 A. terreus). In conclusion, Aspergillus appears to be an important pathogen in Denmark. Elevated itraconazole MICs were detected in 4% of the isolates including a multi-azole resistant isolate.

Fungal Infection of Cystic Fibrosis Patients—Single Center Experience

“…However, in the majority of CF patients, isolation of Aspergillus spp. only confirms colonization and/or diagnosis of allergic bronchopulmonary aspergillosis (6−25%) [20]. The Danish research showed 65.5% of colonization cases of the lower airways with Aspergillus spp.…”

“…The literature reports rare cases of invasive aspergillosis in people with CF. Mortensen et al presented two cases of invasive fungal infection of A. fumigatus etiology [20]. However, in the majority of CF patients, isolation of Aspergillus spp.…”

“…The Danish research showed 65.5% of colonization cases of the lower airways with Aspergillus spp. and 2.7% of cases of ABPA [20]. In Poland, due to lack of register of CF patients suspected ABPA, the only available data are 63 cases of suspected ABPA in CF patients > 18 years of age, which were reported in 2007 [14].…”

“…Resistance to azoles is related to the occurrence of mutation in the cyp51A gene, which is responsible for ergosterol reaction in the fungal cell [20]. Mortensen et al showed that 4% of A. fumigatus strains that were isolated from the CF patients, have a lowered susceptibility to azole drugs [20].…”

“…Mortensen et al showed that 4% of A. fumigatus strains that were isolated from the CF patients, have a lowered susceptibility to azole drugs [20]. Fischer et al found resistance to itra-www.pneumonologia.viamedica.pl conazole (MIC > 8mg/l) and cross resistance to the remaining drugs from the azole group such as voriconazole and posaconazole in 3.4% of A. fumigatus strains [24].…”