Modification of potassium nitrate assimilation test for identification of clinically important yeasts

Abstract

The modification of an auxanographic method used in yeast species identification to determine potassium nitrate (KNO3) assimilation resulted in a simple and inexpensive KNO3 assimilation test medium. The medium provided accurate and reliable results in less than 24 h.

Emergence of fluconazole-resistant strains of Blastoschizomyces capitatus causing nosocomial infections in cancer patients

“…Observations of these fungi developing on potato dextrose agar plates (Unipath S.p.A., Garbagnate Milanese, Milan, Italy) and on cornmeal agar (Unipath) slide cultures confirmed this identification. Isolated yeastlike organisms were unable to utilize potassium nitrate as the sole nitrogen source with a nitrate test medium as reported by others (11). With Christensen urea agar (Unipath), the isolates were unable to hydrolyze urea and, moreover, showed resistance to cycloheximide when plated onto Mycosel (BBL Microbiology Systems, Cockeysville, Md.).…”

Endocarditis caused by Blastoschizomyces capitatus and taxonomic review of the genus

“…Conidial morphology and ontogeny were investigated with 7to 10-day old potato dextrose agar (Difco Laboratories, Detroit, Mich.) and cornmeal agar (Difco) slide cultures. The ability of the isolates to utilize potassium nitrate as the sole nitrogen source was determined with a nitrate test medium as described previously (14). Carbohydrate assimilation patterns were assessed through the use of an API 20C yeast identification kit and verified with API 50CH test strips (API Systems, Montalieu Vercieu, France) (7).…”

Onychomycosis Caused by Blastoschizomyces capitatus

“…Conidial morphology and ontogeny were observed by use of 7-to 10-day-old potato dextrose agar (Unipath s.p.a., Garbagnate Milanese, Milan, Italy) plates and cornmeal agar (Unipath) slide cultures. Potassium nitrate assimilation was determined with a nitrate test medium as reported by others (22). Biochemical tests were performed by using ID32 C strips with an ATB reader (API System; BioMerieux Italia, Rome, Italy).…”