Ticarcillin

β-Lactam antibiotics used were ertapenem (Merck Sharp & Dohme), imipenem (Fresenius Kabi), meropenem (Aurovitas), cefepime (Accord Healthcare), cefoxitin and ceftazidime from Laboratorios Normon (), aztreonam (Bristol-Myers Squibb), as well as doripenem, carbenicillin, piperacillin, ticarcillin, avibactam, relebactam, sulbactam, and tazobactam from MedChem Express. The β-lactam MICs were determined at least in duplicate in strain P. aeruginosa PAO1 following the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method (70 ).

The MIC of β-lactams and β-lactamase inhibitors (BLIs) was determined by the standard Clinical and Laboratory Standards Institute (CLSI) broth microdilution method (43 ). Imipenem was purchased from Fresenius Kabi (Barcelona, Spain); meropenem from Aurovitas (Madrid, Spain); ertapenem from Merck Sharp & Dohme (Haarlem, Netherlands); penicillin G from Laboratorio Reig Jofré SA (Barcelona, Spain); ceftaroline from Pfizer Pharmaceuticals (Ringsend, Ireland); cefotaxime, ceftriaxone, cefoxitin, and ceftazidime from Laboratorios Normon (Madrid, Spain); cefepime from Accord Healthcare (Barcelona, Spain); aztreonam from Bristol-Myers Squibb (Madrid, Spain); and doripenem, cefixime, ceftolozane, amdinocillin, carbenicillin, piperacillin, ticarcillin, avibactam, relebactam, sulbactam, and tazobactam from MedChem Express (Sollentuna, Sweden). ceftazidime-avibactam and ceftolozane-tazobactam MICs were determined by MIC test strip from Liofilchem (Rosetto degli Abruzzi, Italy). MIC values were determined from at least three independent experiments.