Clinical efficacy of temocillin.

tazobactam. The addition of tazobactam was of no benefit in strains producing GES, VEB and PER b-lactamases, which all had CXA-101 MICs .64 mg/L. In the only isolate producing an ESBLM-D b-lactamase (OXA-32), the MIC was reduced from .64 to 8 mg/L. The OXA-32-producing isolate was also susceptible to piperacillin/tazobactam. Susceptibility to piperacillin/ tazobactam was additionally seen in one isolate (producing PER-1), which was resistant to all b-lactams except imipenem and ceftazidime plus clavulanate. The latter combination was found to have activity against four isolates (producing PER-1, BEL-1, SHV-5 and TEM-4). In conclusion, CXA-101 was found to have good in vitro activity against 4/9 ESBLA-producing P. aeruginosa. The addition of tazobactam extended the activity to the one ESBLM-D-producing isolate tested. Hence, CXA-101 plus tazobactam had good in vitro activity against half of the ESBL-producing P. aeruginosa isolates investigated. In comparison, imipenem had activity against 9/10 isolates, ceftazidime plus clavulanate against 4/10 isolates, piperacillin/ tazobactam against 3/10 isolates, cefepime against 2/10 isolates and ceftazidime or ceftazidime plus tazobactam against 1/10 isolates.