Mycology Comparison of Albicans ID2 agar plate with the germ tube for presumptive identification of Candida albicans C.D. Ca ´rdenes a , A.J. Carrillo b , A. Arias a , C. Rodrı ´guez-Alvarez a , A. Torres-Lana a,c , A. Sierra a,c , M.P. Are ´valo a, * a Preventive Medicine and Public Health Department. University of La Laguna, Tenerife, Canary Islands, Spain b Microbiology Department, ACIA, Barcelona, Spain c Hospital Universitario de Canarias, Tenerife, Canary Islands, Spain Received 30 May 2001; accepted 14 November 2001 Abstract Albicans ID2® (bioMe ´rieux, France) is a commercially available chromogenic medium that allows rapid and specific macroscopic identification of Candida albicans and facilitates the differentiation of species in mixed cultures. We compared it with the standard method for the identification of yeast species, the germ tube test (GT). This study involved 423 clinical isolates, including 163 C. albicans and 260 non-albicans yeasts. Sensitivity of Albicans ID2® agar plates regarding the identification of C. albicans were 98.2% after 48 h of incubation and specificity of 96.6%. This method using rapid enzymatic method shows the same similar sensitivity than the GT test The false negative rate (1.8%) for the GT test is consistent with that previously reported. None tests discriminated between C. albicans and C. dubliniensis isolates. © 2002 Elsevier Science Inc. All rights reserved. Keywords: Yeast; Albicans ID2®; Germ tube test; API ID 32C®; Chromogenic medium; Candida albicans; Yeast differentiation and identification 1. Introduction Candidiasis is increasing as a complication in both im- munocompromised and immunocompetent individuals. Candida albicans is the most frequently isolated yeast pathogen, and its incidence is increasing due to the devel- opment of therapeutic modalities for previously fatal neo- plastic diseases, use of corticosteroids as immunosuppres- sants, and an increase in immunocompromising diseases (Elder & Roberts, 1986; Fraser et al., 1992; Louria, 1971; Taschdjian et al., 1970). It is a frequent secondary invader to bacterial pathogens, and the prolonged use of broad- spectrum antibacterial chemotherapy can lead to over- growth of C. albicans and subsequent tissue invasion and systemic disease (Elder & Roberts, 1986). The presumptive clinical identification of C. albicans is usually made on the basis of its ability to produce short, slender, tubelike structures called germ tubes when incu- bated at 30 to 37°C for 2 to 4 h in pooled human serum (Freydie ´re & Guinet, 1997; Hoppe & Frey, 1999; Macken- zie, 1962). Reports indicate that C. tropicalis, C. parapsi- losis and Cryptococcus gastricus also produce structures, which resemble germ tubes (Campbell et al., 1998; Frey- die ´re & Guinet, 1997; Lipperheide et al., 1993; Perry et al., 1990). Moreover, 5% of routine isolates of C. albicans have recently been shown to be germ tube negative (Lipperheide et al., 1993). With opportunistic yeasts isolated more frequently, there is an obvious need for rapid and cost-effective differentia- tion of C. albicans from other Candida species. C. albicans is the yeast species most often isolated from clinical sam- ples, and most clinical laboratories approach yeast identifi- cation by applying rapid tests (Odds & Bernaerts, 1994). It is therefore important to develop rapid identification meth- ods so that early diagnosis and effective empiric antifungal therapy can be started (Baumgartner et al., 1996). The lengthy incubation necessary for biochemical characteriza- tion of clinical yeast isolates may hinder the therapeutic decisions. Although the germ tube test is rapid (2 to 3 h), problems with GT-negative strains of C. albicans (Perry and Miller, 1987; Salkin et al., 1987), misinterpretation of elon- * Corresponding author. Fax: +1-34-922319378. E-mail address: mpareval@ull.es (M.P. Are ´valo). www.elsevier.com/locate/diagmicrobio Diagnostic Microbiology and Infectious Disease 42 (2002) 181–185 0732-8893/02/$ – see front matter © 2002 Elsevier Science Inc. All rights reserved. PII: S0732-8893(01)00346-7