JAC Advance Access originally published online on June 6, 2007
Journal of Antimicrobial Chemotherapy 2007 60(2):312-316; doi:10.1093/jac/dkm192
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Antifungal susceptibility of Cryptococcus neoformans and Cryptococcus gattii isolates from decayed wood of trunk hollows of Ficus religiosa and Syzygium cumini trees in north-western India
1 Mycology Reference Laboratory, Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait 2 Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India
Received 28 January 2007; returned 17 April 2007; revised 8 April 2007; accepted 4 May 2007
* Corresponding author. Fax: +965-5318454/5332719; E-mail: ziauddin{at}hsc.edu.kw
Background: We present antifungal susceptibility data on environmental isolates of Cryptococcus neoformans (serotype A, n = 117) and Cryptococcus gattii (serotype B, n = 65) cultured from decayed wood of trunk hollows of Ficus religiosa and Syzygium cumini trees.
Methods: Susceptibilities to amphotericin B, fluconazole, ketoconazole, itraconazole and voriconazole were determined by using Etest. The MICs were read after 48 h as per the guidelines provided by the manufacturer.
Results: The MIC90s and susceptibility ranges for C. neoformans isolates were as follows: 0.094 (0.0040.25) mg/L for amphotericin B, 4 (0.03212) mg/L for fluconazole, 0.094 (0.0040.75) mg/L for itraconazole, 0.064 (0.0020.19) mg/L for ketoconazole, and 0.047 (0.0060.125) mg/L for voriconazole, whereas for C. gattii isolates these were 0.125 (0.0230.5) mg/L for amphotericin B, 8 (0.03216) mg/L for fluconazole, 0.75 (0.0062) mg/L for itraconazole, 0.125 (0.0030.19) mg/L for ketoconazole, and 0.094 (0.0040.125) mg/L for voriconazole. A comparison of the geometric means of MICs (mg/L) revealed that C. gattii was less susceptible than C. neoformans to amphotericin B (0.075 versus 0.051, P = 0.0003), fluconazole (2.912 versus 2.316, P = 0.003), itraconazole (0.198 versus 0.0344, P < 0.0001), ketoconazole (0.072 versus 0.037, P < 0.0001), and voriconazole (0.045 versus 0.023, P < 0.0001).
Conclusions: The antifungal susceptibility data obtained in this study indicate that the occurrence of primary resistance among environmental isolates of C. neoformans serotype A and C. gattii serotype B is rare, and serotype B isolates are less susceptible than serotype A isolates.
Keywords: Etest , fluconazole , itraconazole , voriconazole , amphotericin B