Prevalence of Candida metapsilosis and Candida orthopsilosis isolates in a Spanish yeast stock collection

Abstract number: P1963

Miranda-Zapico I., Eraso E., Marcos-Arias C., Hernández Almaraz J.L., Carrillo Muñoz A.J., Quindós G.

Objectives: To study the prevalence and antifungal susceptibility of Candida metapsilosis and Candida orthopsilosis among clinical isolates previously identified as Candida parapsilosis.

Methods: One hundred and twenty-one recent clinical isolates from our stock collection yielded during the last years were studied. The isolates included 72 from blood, 22 from genitalia, 19 from mouth and 8 from different clinical specimens. C. parapsilosis ATCC 22019 and ATCC 90018, C. metapsilosis ATCC 96143 and ATCC 96144 and C. orthopsilosis ATCC 96139 and ATCC 96141, were included as reference strains. Isolates were identified as C. parapsilosis by conventional mycological methods. These isolates were differentiated by a two-step DNA-based identification test and AFLP described by Tavanti et al. (Candida orthopsilosis and Candida metapsilosis spp. nov. to replace Candida parapsilosis groups II and III. J Clin Microbiol 2005; 43: 284–292). Briefly, a 716-bp fragment of the SADH (secondary alcohol dehydrogenase) gene was amplified, purified, and digested with BanI. C. parapsilosis, C. metapsilosis, and C. orthopsilosis SADH amplicons contained, respectively, one, three, and zero BanI restriction sites.

Results: One hundred and sixteen isolates were C. parapsilosis sensu lato (95.9%), 3 C. metapsilosis (2.5%) and 2 C. orthopsilosis (1.6%). One isolate each of C. metapsilosis were from blood, genitalia and faeces. C. orthopsilosis was isolated from blood and genitalia. The antifungal susceptibilities to amphotericin B, anidulafungin, fluconazole, micafungin, and voriconazole of both blood isolates of C. metapsilosis and C. orthopsilosis and of 28 randomly-chosen C. parapsilosis blood isolates were tested by the CLSI M27A3 method. These isolates showed the same antifungal susceptibility patterns than C. parapsilosis blood isolates with a non-significant decrease of anidulafungin and micafungin MICs and with a non-significant increase of fluconazole MICs.

Conclusion:C. metapsilosis and C. orthopsilosis were identified as the cause of 2.8% of the invasive candidiasis previously attributed to C. parapsilosis. C. metapsilosis and C. orthopsilosis were also implicated in cases of superficial candidiasis.

Funding: Projects GIC07 123-IT-222–07 (from the Departamento de Educación, Universidades e Investigación, Gobierno Vasco) and PI061895/2006 (from the Fondo de Investigación Sanitaria del Ministerio de Sanidad y Consumo de España).