Penicillin binding protein 3 is a common adaptive target among Pseudomonas aeruginosa isolates from adult cystic fibrosis patients treated with β-lactams.

•pbpB is a common adaptive target among β-lactam exposed cystic fibrosis Pseudomonas aeruginosa isolates•Infecting cystic fibrosis Pseudomonas aeruginosa populations typically carry multiple pbpB alleles•Predicted amino acid changes to penicillin-binding protein 3 are associated with elevated minimum inhibitory concentrations for some β-lactams•ampC or mexA overexpression is uncommon of Pseudomonas aeruginosa with nonsynonymous polymorphisms in pbpB