Summary Resistance Nodulation cell Division (RND) efflux pumps are known to contribute to the tolerance of Pseudomonas putida to aromatic hydrocarbons, but their role in antibiotic resistance has not been fully elucidated. In this study, two types of single‐step multidrug‐resistant (MDR) mutants were selected in vitro from reference strain KT2440. Mutants of the first type were more resistant to fluoroquinolones and β‐lactams...

Summary We recently identified a hypervirulent strain of Pseudomonas aeruginosa , differing significantly from the classical strains in that it lacks the type 3 secretion system (T3SS), a major determinant of P. aeruginosa virulence. This new strain secretes a novel toxin, called ExlA, which induces plasma membrane rupture in host cells. For this study, we collected 18 other exlA ‐positive T3SS‐negative strains, analyzed their...