Voriconazole susceptibility of yeasts isolated from the mouths of patients with advanced cancer

1 Infection and Immunity Section, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow G2 3JZ, UK 2 Department of Palliative Medicine, Royal Marsden Hospital, Downs Road, Sutton, Surrey SM2 5PT, UK 3 Department of Oral Microbiology, GKT Dental Institute, Floor 28, Guy's Tower, Guy's Hospital, London SE1 9RT, UK Correspondence Jeremy Bagg j.bagg{at}dental.gla.ac.uk Received April 27, 2004 Accepted June 27, 2005 The in vitro activity of voriconazole was compared with those of fluconazole and itraconazole against 270 clinical isolates of yeasts from the mouths of patients receiving palliative care for advanced cancer. A broth micro-dilution assay as described by the National Committee for Clinical Laboratory Standards was employed for determination of MICs. Of the 270 isolates, 206 (76 %) were fluconazole sensitive and 64 were fluconazole resistant. Voriconazole showed more potent activity than either fluconazole or itraconazole, including against some isolates resistant to both fluconazole and itraconazole. However, for fluconazole-resistant isolates, the MICs of itraconazole and voriconazole were proportionally higher than for the fluconazole-susceptible isolates, suggesting cross-resistance. Voriconazole may be a useful additional agent for the management of oral fungal infections caused by strains resistant to fluconazole and itraconazole, but susceptibility cannot be assumed and in vitro MIC determination is recommended prior to its use. Abbreviation: NCCLS, National Committee for Clinical Laboratory Standards.