Species distribution in bloodstream isolates of Candida species in Bulgaria and their susceptibility to antifungal agents

Abstract number: 1733_766

Boyanova L., Kantardjiev T., Kouzmanov A., Ivanova Z., Velinov T., Petrov M.

Objectives: The aim of this study is to evaluate species distribution and antifungal susceptibility of Candida bloodstream isolates in Bulgaria. This is a part of surveillance programme, called BulSTAR, which researches the aetiological structure of microorganisms and their susceptibility to antimicrobial agents from 1997 to 2005.

Methods: In the National Reference Laborarory of Mycology, we collected and investigated 277 Candida blood isolates. Species identification was confirmed with VITEK YBC system or with API 20 C AUX, followed by antifungal susceptibility testing of isolates, performed with E-test and microdilution kit Micronaut-AM (Merlin). The results were confirmed with the referent broth microdilution method NCCLS (currently CLSI) M27-A2.

Results: The data from BulSTAR showed that, for the period of 1997 to 2005 from all bloodstream isolated microorganisms, Candida strains are: 2.6% (1997), 1.9% (1998), 2.7% (1999), 3.3% (2000), 2.8% (2001), 2.1% (2002), 2.8% (2003), 2.9% (2004), 5.1% (2005).

In the current study overall species distribution is: 53% Candida albicans, 21% C. parapsilosis, 10% C. glabrata, 3.2% C. krusei, 3.6% C. tropicalis and other non-albicans species. We report one interesting case of infective prosthetic endocarditis, caused by C. rugosa, isolated only from the mitral valve.

Minimal inhibitory concentrations (MICs) of fluconazole, read at 24–48 h are: 0.75–2 mg/L for C. albicans, 12–32 mg/L for C. glabrata, 1.5–3 mg/L for C. parapsilosis, 48–64 mg/L for C. krusei. MIC of voriconazole is: 0.023–0.032 mg/L for C. albicans, 3–6 mg/L for C. glabrata, 1–2 mg/L for C. parapsilosis, 2–3 mg/L for C. krusei.

Conclusion: These data suggest that, in Bulgaria the species distribution of Candida bloodstream infections and their antifungal susceptibility rate are similar to those reported in Europe and North America. The highest percentage of non-albicans species identified are C. parapsilosis and C. glabrata.