FTIR characterization of Candida species:: a study on some reference strains and pathogenic C-albicans isolates from HIV+ patients

ATR-FTIR has been used together with principal components analysis to study some reference strains belonging to five different Candida species and 20 Candida albicans isolates from three HIV+ patients under different fluconazole regimens. The five reference strains were easily differentiated by using first derivative spectra of the carbohydrate region comprising the spectral range 900-1200 cm(-1). For the C. albicans clinical isolates. classification obtained by Fourier-transform infrared (FTIR) spectroscopy was compared with data from the genotypic method, PFGE. Results show a good correlation between the two methods for one patient who presented a partially conserved immune system with no previous fluconazole treatment, where all C. albicans strains isolated were susceptible to this antifungal agent. Divergences in the two methods appear for the two immuno-compromised patients receiving long-term fluconazole treatment. It is very probable that such iterative antifungal treatment can cause strong alterations in the yeast cell wall membrane and that the mismatch of the two techniques highlights the complex situation of strain-level identification and differentiation of clinical isolates originating from patients under prolonged treatment. (C) 2002 Elsevier Science B.V. All rights reserved.