Colistin susceptibility testing: evaluation of reliability for cystic fibrosis isolates of Pseudomonas aeruginosa and Stenotrophomonas maltophilia

Abstract

Compared with agar dilution, other susceptibility testing methods give high rates of apparent false polymyxin susceptibility for cystic fibrosis isolates of P. aeruginosa and S. maltophilia. Prospective study of the correlation between in vitro susceptibility and clinical response is needed to clarify whether these discrepancies reflect oversensitivity of the agar dilution method or insensitivity of the other methods.