TABLE 4

Antibiotic susceptibilities of K. pneumoniae strains, combination CAZ-AVI, and effect of PMBN

StrainMIC (mg/liter)a
CHLPAβNNORNALCIPPIPAVIPMBNCAZCAZ + AVI 1CAZ + AVI 2CAZ + AVI 4CAZ + PMBNAVI + PMBNCAZ + PMBN + AVI 1CAZ + PMBN +AVI 2CAZ + PMBN + AVI 4CPTIPMMEMATMERT
ATCC 11296440.25160.0616>1282560.250.50.50.1250.251280.50.25ND10.250.030.1250.25
KP45161,0240.2540.0681281,0240.50.1250.060.50.125160.060.060.060.250.1250.030.060.01
KP55161,024161,0242128128>1,024128441480.250.1250.0680.250.06>1281
KP635121,0241320.1256416512512882880.51180.250.06>1281
KP7485120.2540.06>1,024645122,0486416864160.50.250.251280.250.06641
KP801281,02416>1,0248>1,024161,0248420.250.12580.1250.1250.12580.060.0310.5
KP891281,02416>1,0248128321,02420.50.50.250.12580.1250.1250.0610.1250.030.250.06
  • a CHL, chloramphenicol; PAβN, phenylalanine-arginine β-naphthylamide; NOR, norfloxacin; NAL, nalidixic acid; CIP, ciprofloxacin; PIP, piperacillin; AVI, avibactam (1, 2, or 4 mg/liter); PMBN, polymyxin B nonapeptide (used at MIC/10 for combination); CAZ, ceftazidime; CPT, ceftaroline; IPM, imipenem; MEM, meropenem; ATM, aztreonam; ERT, ertapenem; ND, not determined because of intrinsic susceptibility preventing the reading of a reliable endpoint.