Molecular typing of clinical and environmental Aspergillus fumigatus isolates with random amplification of polymorphic DNA

E. Sodja, T. Kavcic, T. Matos

Author address: 

Institute of Microbiology and Immunology, LJUBLJANA, Slovenia

Abstract: 

Objectives: Aspergillus fumigatus is an opportunistic fungus responsible for invasive aspergillosis in immunocompromised people. In nature, this fungal species grows on decaying vegetation and releases large amounts of conidia in air. Patient infection is acquired upon inhalation of conidia. Since treatment of invasive aspergillosis is difficult and the outcome is often fatal, identification of infective strains and sources of infection is a major epidemiological concern in many studies of nosocomial aspergillosis. Techniques of molecular biology have been extensively used for typing A. fumigatus isolates. The most popular technique for molecular typing of A. fumigatus isolates is based on random amplification of polymorphic DNA (RAPD). Here we report genotyping analysis of clinical and environmental A. fumigatus strains to find out if cases of aspergillosis in an individual patient were caused by hospital acquired strains of A. fumigatus. Methods: Three clinical and thirty-seven environmental isolates were included in this study. Clinical isolates of A. fumigatus were collected from patients with proven invasive aspergillosis of lung nursed in three departments of University Medical Centre Ljubljana, Slovenia: Department of Intensive Internal Medicine, Department of Anaesthetics and Surgical Intensive Care and Department of Nephrology. Environmental isolates were collected with air sampling method in patients’ rooms and shared areas of the departments. After extraction of DNA with PureLink Genomic DNA Mini Kit (Invitrogen, Carlsbad, USA), each A. fumigatus isolate was genotyped using RAPD analysis. The primer used for RAPD typing was R108. Results: RAPD analysis of environmental and clinical isolates of A. fumigatus allowed identification of thirteen distinct profiles among 40 isolates. All three strains isolated from patients have distinct profiles; two of them were isolated only from patients and not from the environment. One strain isolated from patient nursed in Department of Intensive Internal Medicine was found to be identical to environmental strains collected from air of hallway and room of Department of Nephrology. Some environmental strains with identical RAPD profiles were collected from air of all three departments. Conclusions: Thirteen distinct profiles were identified by RAPD analysis, indicating great genetic diversity of A. fumigatus strains isolated from infected patients and from their hospital environment. In one case, a genetic similarity was noted between isolate obtained from patient and isolates from the hospital environment.
2009

abstract No: 

P221

Full conference title: 

4th Trends in Medical Mycology
    • TIMM 4th (2012)