Aztreonam

Amoxicillin, ciprofloxacin, ofloxacin, clindamycin, cefotaxime, and piperacillin were purchased from Sigma (St. Gallen, Louis, MO, USA). Monohydrate cefepime dichlorhydrate was supplied from Gerda (Paris, France). Trihydrate meropenem and sodium cefoxitin were supplied from Panpharma (Fougères, France). Pentahydrate ceftazidime and sodium cefazolin were supplied from Mylan (Saint Priest, France). Ertapenem was supplied from MSD (Puteaux, France). Daptomycin was supplied from Medac SAS (Lyon, France). Aztreonam was supplied from Sanofi Aventis (Gentilly, France). Linezolid was supplied from Fresenius Kabi (Sevres, France). Internal standards (Amoxicillin-D₄, cefazolin-¹³C₂¹⁵N, meropenem-D₆, ofloxacin-D₈, ciprofloxacin-D₈, piperacillin-D₅, cefotaxime-D₃, and Linezolid-D₃) were purchased from TRC (Toronto, ON, Canada). Acetonitrile, methanol, formic acid, and water, all LC-MS hypergrade for mobile phase, were obtained from Biosolve (Dieuze, France). Plasma was purchased from the French Blood Bank (“Etablissement Français du Sang”, EFS, Reims, France).

Mecillinam (Karo Pharma, Stockholm, Sweden), ceftazidime/avibactam (Pfizer, Kent, UK), avibactam (MedChemExpress, Monmouth Junction, NJ, USA) and ceftazidime (Fresenius Kabi, Singapore) were dissolved in MilliQ water. The fluorescent penicillin Bocillin FL (Invitrogen, Eugen, OR, USA) was used to label penicillin-binding proteins (PBPs) in the Bocillin FL assay. In addition, cefsulodin (Glentham Life Sciences Ltd., Corsham, UK), aztreonam (Sanofi-aventis, Paris, France) and cefoxitin (Novopharm Limited, Toronto, ON, Canada) were used as control antibiotics in the Bocillin FL assay.