Analysis by pulsed-field gel electrophoresis of Candida albicans that developed resistance during antifungal therapy.

A patient with myelofibrosis complicated by recurrent candidemia died despite treatment with amphotericin B and fluconazole. Autopsy revealed systemic candidiasis with fungal verrucae in the right ventricle and the root of the pulmonary artery. The strains of Candida albicans isolated from the blood had become resistant to amphotericin B and fluconazole during therapy, as well as to other azole antifungals that had not been used. Pulsed-field gel electrophoresis showed that the resistant isolates had the same genotype as the sensitive strains isolated before treatment, but a chromosomal change in >2.0 Mb-bands was observed after treatment. It was thus proved that these repeatedly isolated C. albicans strains which were causing the continued fungemia in our patient were all the same strain and were acquiring resistance to antifungal agents during the therapy.