Differential diagnosis in bloodstream infection with Trichosporon asahii and Geotrichum capitatum / 中国感染控制杂志

ABSTRACT

Objective To provide reference for establishing diagnosis and differential diagnosis methods of rare yeast-like fungal bloodstream infection for clinical microbiology laboratory.Methods Trichosporon asahii (T.asa-hii)and Geotrichum capitatum (G.capitatum)bloodstream infection was diagnosed and differentially diagnosed through clinical data analysis,morphological examination,biochemical reactions,and molecular biology technology. Results Two types of yeast-like fungal bloodstream infections in case 1 and case 2 both occurred in leukemia agranulocytosis phase after chemotherapy,such infections were serious and highly similar.The cultivated colonies on blood agar plates of case 1 and case 2 were performed gram stain and microscopic examination.Hyphae,arthro-spores and microconidia were visible in the former,thickness of hyphae branches and length of arthrospores were different,most presented rectangular and barrel shape;the latter can be seen hyphae with transparent septum bro-ken up into arthrospores,presented rectangular shape,did not produce blastoconidia.Identification with API 20C AUX showed that they were T.asahii and G.capitatum.The PCR product sequences were compared with NCBI, suggesting that T.asahii and G.capitatum were at sexual stage.Conclusion Comprehensive application of a varie-ty of technical methods is helpful for improving the diagnosis accuracy of bloodstream infection with yeast-like fungi, identifying Trichosporon and Geotrichum to the species level may help physicians to understand such rare fungal in-fection,choose antifungal agents rationally,and improve clinical prognosis.