1. A 32-year-old m ale heroin addict was adm itted to the hospital w ith a 2-day history of fever, shaking chills, rigors, and night sweats. His vital signs were blood pressure 100/60 m m Hg, pulse...

1. A 32-year-old m ale heroin addict was adm itted to the hospital w ith a 2-day history of fever, shaking chills, rigors, and night sweats. His vital signs were blood pressure 100/60 m m Hg, pulse 120 bpm , respirations 24/m in, temperature 102.2°F (39°C). Two-dim ensional echocardiography revealed three sm all vegetations on the tricuspid valve. Three blood cultures were draw n, and em piric therapy was initiated. The cultures turned out to be positive for Pseudom onas aeruginosa, w ith the follow ing antibiotic susceptibilities: Drug Minimum Inhibitory Concentration Gentamicin 16 µg/mL Tobramycin 2 µg/mL Piperacillin 64 µg/mL Ceftazidime 4 µg/mL Imipenem 2 µg/mL Surgical excision of the infected valve and a 6-week postoperative treatm ent were planned. Which of the follow ing drug com binations would be m ost appropriate for the patient at this tim e? A. Tobramycin and gentam icin B. Ceftazidim e and tobramycin C. Im ipenem and gentam icin D. Ceftazidim e and im ipenem E. Piperacillin and tobramycin