First itraconazole resistant Aspergillus fumigatus clinical isolate harbouring a G54E substitution in Cyp51Ap in South America.

ABSTRACT

BACKGROUND: A 27-year-old male rural worker was admitted with a fungal keratitis due to an injury involving plant detritus. MATERIALS AND METHODS: Specimens were collected for microscopy examination and culture. The isolate was identified by morphological and molecular criteria. Susceptibility testing was performed using CLSI methods. CYP51A gene was PCR amplified and sequenced. RESULTS: An Aspergillus fumigatus strain resistant to itraconazole (MIC>8µg/ml) was isolated. The isolate was susceptible to amphotericin B, posaconazole, voriconazole and caspofungin. CYP51A sequencing showed two mutations leading on the G54E substitution. The patient received natamycin as treatment. CONCLUSIONS: This is the first report in South America of a clinical A. fumigatus strain carrying the substitution G54E at Cyp51Ap associated with itraconazole resistance. Considering the patient was azole-naive, this resistant isolate may have been acquired from the environment.