Culture-positive invasive aspergillosis in a medical center in Taiwan, 2000-2009.

We reviewed 776 patients who were culture positive for Aspergillus species at the hospital from 2000 to 2009. The isolates were collected for species identification by oligonucleotide hybridization and sequence analysis. A total of 96 cases of proven or probable IA were identified according to published criteria. The incidence of IA has increased significantly during the study period. Aspergillus fumigatus and A. flavus (41.7% each) were equally prevalent causative species. IA due to unusual species including A. nidulans (n=2), A. versicolor (n=2), and A. tubingensis (n=1) were also found. Among patients with IA, 55.2% had hematological disorder, 19.8% had underlying lung disorder, and 10.4% had autoimmune disease. The isolates species (P<0.001) and underlying disease (P<0.001) significantly affect the association of a positive culture with invasive disease. The overall mortality at three months was 62.5%, which remained stable throughout the study period. Multivariate analysis identified prior steroid use (P=0.007) as a significant risk factor for death, while surgery (P=0.030) and voriconazole (P=0.012) had protective effects. In conclusion, autoimmune disorders and underlying pulmonary diseases should also be considered as important predisposing factors of IA. Further emphasis on surgery and voriconazole in the management of IA might be beneficial.

Invasive infections caused by non-Aspergillus moulds identified by sequencing analysis at a tertiary care hospital in Taiwan, 2000-2008.

The clinical and microbiological characteristics of 103 patients with cultures positive for non-Aspergillus moulds in the period 2000 to 2008 were described. Among these patients, 27 had proven or probable invasive infections caused by Fusarium (n = 12), Paecilomyces (n = 7), Zygomycetes (n = 5) and Scedopsorium species (n = 3). The incidence of invasive infections caused by these moulds has not increased during the study period. Lung was the most common infection site and disseminated disease was observed in three leukaemic patients. The overall mortality rate was 40.7%, and was highest in cases zygomycosis. Antifungal susceptibility varied considerably among species. Amphotericin B and posaconazole demonstrated greatest activity against these moulds.

Rapid identification of fungal pathogens in positive blood cultures using oligonucleotide array hybridization.

Identification of fungal species in positive blood cultures using conventional methods can be time-consuming, particularly for non-albicans Candida species, non-Candida yeasts, and moulds. An oligonucleotide array system targeting the internal transcribe spacer (ITS) 1 or 2 region of the rRNA genes was used to analyse prospectively 116 fungus-positive blood cultures [BACTEC Myco/F Lytic bottles (Becton-Dickinson Microbiology Systems, Sparks, MD, USA)] from 105 patients, and the results were compared with those obtained using conventional methods. A total of 124 yeast isolates and two mould isolates were identified; these microorganisms (isolate no.) included C. albicans (50), C. tropicalis (26), C. glabrata (18), C. parapsilosis (14), Cryptococcus neoformans (9), Trichosporon asahii (2), Rhodotorula mucilaginosa (2), Penicillium marneffei (2) and three other species. Multiple species fungaemia (MSF) was detected in ten samples as opposed to six detected using conventional methods. In two discrepant samples, antifungal susceptibility testing revealed that the additionally detected isolate had higher MICs of fluconazole. An isolate reported as Rhodotorula glutinis by the Vitek Yeast Biochemical Card (bioMérieux Vitek, Marcy l'Etoile, France) was identified as R. mucilaginosa by the array and the identification by array hybridization was confirmed by sequence analysis of the ITS region. A test sensitivity of 100% was obtained. The test specificity was 100% according to examination of 57 blood samples containing non-target fungal species or bacterium only. From the time at which growth was detected in blood cultures, the entire identification procedure could be completed within 16-24 h.