Resistance or adaptation? How susceptible is a 'glutaraldehyde-resistant' Pseudomonas aeruginosa isolate in the absence of selection pressure?

The activities of glutaraldehyde solution and an instrument disinfectant based on glutaraldehyde on a Pseudomonas aeruginosa isolate with reduced susceptibility to glutaraldehyde after the first and fifth passages were determined using three concentrations and temperatures. No significant difference was found between the first and fifth passages so phenotypic adaptation is unlikely.