1. A 22-year-old wom an consulted her physician because of a postpartum breast infection. A Gram stain of the pus revealed gram -positive bacteria, and a susceptibility test showed resistance to all...

1. A 22-year-old wom an consulted her physician because of a postpartum breast infection. A Gram stain of the pus revealed gram -positive bacteria, and a susceptibility test showed resistance to all ß-lactam antibiotics. Which of the follow ing bacteria was m ost likely the o ending pathogen? A. Listeria m onocytogenes B. Methicillin-resistant Staphylococcus aureus C. Escherichia coli D. Streptococcus pyogenes E. Enterococcus faecalis F. Clostridium tetani G. Serratia m arcescens 2. A 4-year-old boy w as brought to the pediatrician by his m other because of respiratory di culties. Medical history of the boy was signi cant for recurrent pulm onary infections. A Gram stain of the sputum revealed gram -positive cocci in grapelike clusters. W hich of the follow ing drugs would be an appropriate em piric treatm ent at this early stage? A. Penicillin G B. Am picillin C. Piperacillin D. Dicloxacillin E. Am oxicillin