engleski

Possible toxicity of clinical isolates of C. albicans

INTRODUCTION: Opportunistic dimorphic yeast C. albicans (CA) is part of normal harmful commensal human flora but small changes in local or systemic immune system, or other injuries could promote invasiveness of CA. CA may cause a broad spectrum of diseases ranging from mucocutaneous to systemic infection. Except host factors (immune status, protective barriers), CA secreted hydrolytic enzymes: proteases, phospholipases, lipases and hemolysins, and these enzymes contribute pathogenicity. The aim of this research was to isolate and detect lipophilic low-molecular-weight (LMW) metabolites of CA with possible toxicity. MATERIAL AND METHODS: CA (N=60) were collected from patient with vaginitis, urinary-tract infection, and from blood (fungaemia). Non-pathogenic CA (N=30) was isolated from mouth and stool specimens. Production of LMW metabolites were performed using method described by Shah and Larsen (1) in Minimal essential medium (MEM), and influence of dimorphism (monocell yeasts or (pseudo)hyphae formation under influence of CO2 and foetal calf serum) were also investigate. Using HPLC/DAD system (2, 3), LMW metabolites were isolated and separated. Chemical structure of isolated compound(s) was determinate using spectral data, retention time, retention index and mass-spectrometry. Concentration was calculated with HPLC using calibration curve with known concentration of standard vs. peak area. RESULTS: All investigated CA strains produce metabolite which UV spectra have maximum at 224 and 279 nm and minimum at 243 nm. Using library of mycotoxins, this metabolite has similar UV spectra and retention time as indol-compounds. This metabolite was identified as 3-indoleethanol (tryptophol) after comparison of negative mode electron spray (EI) MS spectral data of a reference compound. This metabolite displays a base peak at m/z 160 and MS2 were observed at m/z 130 (100%), 116 (33%), and 142. Concentration of 3-indoleethanol ranged from 8.3 μ g/mL to 124.6 μ g/mL, and its production is similar when CA is in yeast (monocell) shape or (pseudo)hyphae. There were no differences between clinical and commensal CA isolates. Gliotoxin was not detected. CONCLUSION: 3-indoleethanol was confirmed as major LMW metabolite of CA. The investigation of toxicity and antimicrobial activity as possible role of 3-indoleethanol in virulence of CA and other Candida spp. is next step in our research. 1) DT Shah and B Larsen, Mycopatholog. 116 (1991) 203-208. 2) JC Frisvad, J. Chromatogr. 392 (1987) 333-347. 3) KF Nieslen and J Smedsgaard, J. Chromatogr. A 1002 (2003) 111-136. Acknowledgement We wish to thank FEMS for supporting research of I. Kosalec

Candida; C. albicans; virulence; toxicity; tryptophol

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