Use of chromogenic medium in the isolation of yeasts from clinical specimens

Department of Medicine, Infectious Disease Service 1 and Department of Pathology and Area Laboratory Support 2 , Brooke Army Medical Center, Fort Sam Houston, TX, USA Correspondence D. R. Hospenthal Duane.Hospenthal{at}amedd.army.mil Received October 29, 2004 Accepted June 27, 2005 Over a 1 year period 3296 specimens submitted for fungal culture were plated onto routine mycological media (RM) and CHROMagar Candida (CaC) to evaluate the capability of CaC to improve on RM. With RM, cultures producing single yeast isolates were identified from 802 specimens. CaC produced similar results, with 76 % agreement. Of 761 specimens that yielded a single Candida species by RM, 615 (81 %) produced one or more yeast isolates using CaC. Of concern, 132 negative CaC cultures corresponded to specimens that yielded C. albicans alone on RM. When yeasts were recovered, CaC correctly identified 98 % of C. albicans , 93 % of Candida tropicalis , 96 % of Candida glabrata and 100 % of Candida krusei based on typical colours. CaC did potentially improve on RM by detecting yeasts in 91 specimens that yielded none by routine methods. CaC was noted to recover more yeast isolates than RM when mixed cultures were detected. Overall, the role of CaC in improving RM appears limited. Present address: Department of Clinical Investigation, Brooke Army Medical Center, Fort Sam Houston, TX, USA. Present address: Epidemiological Surveillance Laboratory, Brooks City Base, San Antonio, TX, USA. Abbreviations: CaC, CHROMagar Candida; CSF, cerebrospinal fluid; RM, routine mycological media.