Abstract

Studies of cystic fibrosis (CF) patient exacerbations attributed to Pseudomonas aeruginosa infection have indicated a lack of correlation of outcome with in vitro susceptibility results. One explanation has been that media for testing do not mimic the airway milieu, resulting in incorrect conclusions. Therefore media have been devised to mimic CF sputum. Aspergillus fumigatus is the leading fungal pathogen in CF, and susceptibility testing also is used to decide therapeutic choices. We assessed whether media designed to mimic CF sputa would give different fungal susceptibility results than classical methods, assaying voriconazole, the most utilized anti-Aspergillus drug in this setting, and 30 CF Aspergillus isolates. The frequency of marked resistance (defined as MIC >4 mcg/ml) in our CF unit by classical methods is 7%. Studies with classical methods and with Digested Sputum Medium, Synthetic Sputum Medium, and Artificial Sputum Medium revealed prominent differences in Aspergillus susceptibility results, as well as growth rate, with each medium. Clinical correlative studies are required to determine which results are most useful in predicting outcome. Comparison of MICs with non-CF isolates also indicated the CF isolates were generally more resistant.

View details for DOI 10.1128/AAC.02649-15

View details for PubMedID 26810647