Image: The fungi Malassezia pachydermatis (Photo courtesy of the Pathogenic Fungi Database).
Hundreds of tiny fungal particles have been found in the lungs of asthma sufferers and could offer new clues in the development of new treatments.
There is increasing evidence that microorganisms are present even in healthy lungs and this finding raises the possibility of a potential overlap between pathogenic and commensal microbiota in the respiratory tract.
A team of scientists at Cardiff University (UK) used molecular techniques to identify eukaryote species that were present in induced sputum samples taken from 30 asthma patients and 13 nonatopic controls. Patients had a mean age of 41.6 years and control participants had a mean age of 35.7 years. The patient group was 40% male and the control group was 46% male.
DNA was extracted from the sputum samples and was amplified using a polymerase chain reaction (PCR) protocol for the partial 18S ribosomal ribonucleic acid (rRNA) gene using primer pairs. The two pooled extract amplicons, from asthma patients and from controls, were sequenced using a 454 pyrosequencer by Research and Testing Inc. (Lubbock, TX, USA). A total of 136 fungal species were identified in the induced sputum samples, with 90 species more common in asthma patients and 46 species more common in control subjects, based on the percent of total DNA reads. The fungi Malassezia pachydermatis
, was found in patients with asthma and not the control group. Two of the fungi most commonly found in the sputum of asthma patients were Termitomyces clypeatus
and Psathyrella candolleana,
both represent members of the basidiomycete family.
Hugo Cornelis van Woerden, MBChB, MPH, the senior author said, “Historically, the lungs were thought to be sterile. Our analysis found that there are large numbers of fungi present in healthy human lungs. The study also demonstrates that asthma patients have a large number of fungi in their lungs and that the species of fungi are quite different to those present in the lungs of healthy individuals. In the future it is conceivable that individual patients may have their sputum tested for fungi and their treatment adjusted accordingly.” The study was published on February 5, 2013, in the Biomed Central’s journal BMC Infectious Diseases.
Research and Testing Inc.