Evaluation of possibilities in identification and susceptibility testing for Candida glabrata clinical isolates with the Integral System Yeast Plus (ISYP)

Abstract

The aim of this study was to evaluate possibilities of correct identification and susceptibility testing of C. glabrata clinical isolates with Integral System Yeast Plus (ISYP). For species identification, as the reference method, API Candida test and species-specific PCR reactions were used. The potential of antifungal susceptibility testing by the ISYP test was compared with the Sensititre Yeast One. Whilst the reference methods confirmed that the received population (n = 65 isolates) represented only C. glabrata, identification with the ISYP system showed correct data only in the case of 18 strains tested (27.7%). Species identification of the other 47 strains with the ISYP test was not possible at all. Significant differences were also observed for drug susceptibility testing carried out by the ISYP and the Sensititre Yeast One. The highest level of disagreement in classifying strains as resistant or susceptible estimated, as 73.9% and 40.0%, was observed for itraconazole and amphotericin B, respectively. Satisfactory results were only obtained for 5-fluorocytosine with 93.8% agreement between both methods. In our opinion the idea of the ISYP system is certainly good. The combination of identification ability and drug susceptibility testing in one test is very important, especially from a clinical point of view. However, the current version of the ISYP has many disadvantages. We would like to encourage the manufacturer to make an effort and develop a new, more accurate version of the test.