Molecular epidemiology of Scedosporium apiospermum infection determined byPCR amplification of ribosomal intergenic spacer sequences in patients with chronic lung disease

Respiratory tract colonization with Scedosporium apiospermum in patients wi th chronic suppurative lung disease is a significant concern for lung trans plantation candidates, since Scedosporium infections occurring posttranspla ntation are usually untreatable. Up to 10% of patients with cystic fibrosis attending our respiratory medicine unit have had Scedosporium organisms is olated from sputum samples. We therefore developed a molecular typing metho d to examine these isolates. Typing by PCR amplification of ribosomal inter genic spacer sequences demonstrated 20 different types from 52 isolates col lected from the respiratory medicine unit and elsewhere in Australia. A sin gle common type was isolated from 11 respiratory medicine unit inpatients. Two other types were isolated from more than one source: one from two respi ratory medicine unit inpatients and one from two epidemiologically linked n onhuman sources. Multiple isolates were obtained from nine patients. This m ethod demonstrated persistent carriage of isolates of the same type in one patient for 7 months. Two patients showed carriage of isolates with multipl e typing patterns within a 3-month period. The high rate of isolation and t he predominance of isolates with a single typing pattern from respiratory m edicine unit patients may suggest transmission to patients from a source in the unit. There was no epidemiological evidence of direct patient-to-patie nt spread, and Scedosporium organisms were not isolated from dust, soil, or air samples from the unit. The source and route of transmission have yet t o be determined.