1. A 79-year-old fem ale resident of a nursing facility complained of burning on urination and bladder pain. Microscopic exam ination of urine sedim ent revealed m any gram -positive bacteria, and a...

1. A 79-year-old fem ale resident of a nursing facility complained of burning on urination and bladder pain. Microscopic exam ination of urine sedim ent revealed m any gram -positive bacteria, and a urine culture indicated Enterococcus faecalis as the sole causative agent. Which of the follow ing pairs of drugs would be m ost appropriate for the treatm ent of this patient? A. Cefotetan and netilm icin B. Cefepim e and am ikacin C. Penicillin G and erythromycin D. Am picillin and tobramycin E. Aztreonam and gentam icin 2. A 54-year-old wom an presented to her physician com plaining of vaginal itching and a thick, w hite vaginal discharge. One week earlier, the wom an had started treatm ent w ith am oxicillin because of a skin infection. Subsequent exam s led to the diagnosis of candida vaginitis that the physician thought w as a superinfection related to the am oxicillin treatm ent. Which of the follow ing best explains w hy broad-spectrum penicillins can cause superinfections? A. Im pairm ent of host im m unologic defense B. Selection of viral-resistant m utants C. Masking disease sym ptom s D. Im pairm ent of norm al m icro ora of the host E. Im pairm ent of norm al in am m atory reaction