Investigation for azole resistance mediating Aspergillus fumigatus cyp51A gene mutations using improved PCR assays and consecutive DNA sequence analysis in clinical samples of immunocompromised patients

B. Spiess*, W. Seifarth, M. Reinwald, N. Merker, S. Will, W.K. Hofmann, D. Buchheidt

Author address: 

(Mannheim, DE)


Objectives: The incidence of azole resistance in Aspergillus fumigatus, the major fungal pathogen causing invasive aspergillosis (IA) in immunocompromised patients, is rising. As the diagnosis of IA is rarely based on positive culture yield in this group of patients, detection of azole resistance directly from clinical samples isin isolate #3 (S80P). The MLST data suggested isolate #2 and #3 were clonally related since DNA sequences in six housekeeping genes were 100% identical and shared a unique pubMLST sequence type. Conclusion: To our knowledge, this is the first report of a stepwise development in vivo of a heterozygous to homozygous S80P mutation in C. tropicalis after caspofungin treatment and despite 1 month of suppressive fluconazole therapy. Even the heterozygous mutant isolate was classified as echinocandin resistant illustrating the importance of the codon S80 of C. tropicalis. This study may contribute to our understanding of resistance development in vivo as a consequence of antifungal treatment. urgently needed.

abstract No: 


Full conference title: 

22nd European Congress of Clinical Microbiology and Infectious Diseases
    • ECCMID 22nd (2012)