My chrysosporium is a scedosporium

Affiliations

Department of Family Medicine, Aurora UW Medical Group, Center for Urban Population Health

Presentation Notes

Presented at 2013 Aurora Scientific Day, Milwaukee, WI

Abstract

Background/significance: A mold which phenotypically resembles and has the same unusual ammonia tolerance as Blastomyces dermatitidis was previously isolated in-vitro from soil. It was tentatively identified as Chrysosporium zonatum.

Purpose: To positively identify and determine the ubiquity of this organism which may be pathogenic and share a microenvironment with B dermatitidis. Methods: The original isolate was identified by expert phenotypic analysis and internal transcribed spacer region rDNA (ITS) sequencing and BLAST search. 10 soil samples were obtained from a yard, park and riverbank in suburban Milwaukee County, November 5, 2012 (5.6 °), diluted two-fold in aqueous 0.5% allantoin, Tween-80 (20 ml/l) and penicillin/streptomycin and incubated at 37º. Three weeks later, samples were spread on low glucose, high (13.2 mM) ammonia basic salts agar plates at pH=7.5 at 37° in gas impermeable bags. New isolates were examined, and compared to the original isolate, on Sabouraud dextrose agar (SDA) at 20° and 37° for colony size, morphology and microscopic appearance.

Results: The original isolate was identified as Scedosporium apiospermum, a fungus associated with opportunistic, traumarelated and other human infections which has been isolated from feces, sewage, soil and other materials. A phenotypically similar strain was isolated from 3/4 samples from the yard (beneath the dryer vent that yielded the original isolate, under a woodpile and next to a sandbox). No colonies formed on plates from the other 7 samples.

Conclusion: Scedosporium apiospermum may compete with Blastomyces in high-ammonia environments, and may be specifically enriched by this 2-step soil isolation technique, suggesting the need for test modification to favor Blastomyces isolation. Ammonia tolerance may explain the finding of Scedosporium in feces and sewage.

Document Type

Abstract

Link to Full Text

 

Share

COinS