23 Rainer et al. [14] developed a selective SceSel+ medium containing dichloran and benomyl as active compounds, which inhibits a large diversity of filamentous

fungi. The SceSel+ medium prevented growth of Aspergillus in sputum samples; Scedosporium strains are overgrown or outcompeted on full medium by Aspergillus strains, due to faster growth rates of A. fumigatus strains. Blyth et al. [13] shows that benomyl-media are significantly more efficient for selective isolation of Scedosporium species than for routine media such as SGA, with up to 100% see more recovery of Scedosporium from spiked samples when SceSel+ was used. When sputum samples are processed with benomyl-based media, recovery rates

tend to increase significantly: Horréet al. [24] noted 14.3% positive samples and Blyth et al. [13] 14.7%. Although our isolation procedure included the use of DRBC-benomyl agar, our isolation rate (8.5% positive) was somewhat in the lower range. When experimental non-culture methods are used to detect Scedosporium in CF sputum samples, significantly higher recovery rates are obtained. Cimon et al. [15], using counterimmuno-electrophoresis were able to raise the detection rate to 21.1% positive samples, compared to 8.6% with classical JAK inhibitor culture. In the present study, we found 62.7% of the samples positive by PCR-RLB. The phenomenon that PCR-based diagnostic Pazopanib mouse assays detect substantially more positives is an often-encountered problem.

A disadvantage of PCR is the risk of false-positive results, caused by either pre-PCR contamination of samples, non-specific amplification or by amplification of DNA from dead cells. Careful precautions against cross-contamination were taken during sample collection and preparation by using separated rooms and filtered tips. No cross reaction or false positive in tester strains was found. All clinical samples were processed twice and identical results were obtained. Therefore, the chance of false-positivity due to contamination or non-specific amplification is negligible. In 10 samples two or three species were detected. These results suggest the regular inhalation of fungal spores belonging to different species of the P. apiosperma/P. boydii complex and the subsequent colonisation of the respiratory tract or at least their persistence in the airways.10 The prevalence of Scedosporium DNA in the environment and the air presently is unknown, which hampers to ascertain whether or not real colonisation has taken place in patients with positive samples. To clarify this, further study is necessary. In one case, PCR-RLB was negative although the sample was proven to be positive by culture. The single deviating Scedosporium culture-positive sample was repeatedly negative using PCR-RLB and remained so with a 1 : 5 dilution of the DNA extract.