The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 36-year-old man undergoes open reduction and internal fixation of a left femur fracture sustained after a motor vehicle collision. Three days after the surgery, he develops fever and redness around the surgical site. His temperature is 39.5°C (103.1°F). Physical examination shows purulent discharge from the wound with erythema of the surrounding skin. Wound culture of the purulent discharge shows gram-positive cocci in clusters. Treatment with oral dicloxacillin is initiated. Four days later, the patient continues to have high-grade fever, pain, and purulent discharge. Which of the following characteristics of the infecting organism best explains the failure to improve with antibiotic therapy?   (A) Presence of an impenetrable outer membrane   (B) Ability to cleave β-lactam rings   (C) Development of efflux pumps   (D) Adaptation in binding proteins
['(D) Adaptation in binding proteins <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Presence of an impenetrable outer membrane \n (B) Ability to cleave β-lactam rings \n (C) Development of efflux pumps \n (D) Adaptation in binding proteins <> possible answers', '  A 36-year-old man undergoes open reduction and internal fixation of a left femur fracture sustained after a motor vehicle collision. Three days after the surgery, he develops fever and redness around the surgical site. His temperature is 39.5°C (103.1°F). Physical examination shows purulent discharge from the wound with erythema of the surrounding skin. Wound culture of the purulent discharge shows gram-positive cocci in clusters. Treatment with oral dicloxacillin is initiated. Four days later, the patient continues to have high-grade fever, pain, and purulent discharge. Which of the following characteristics of the infecting organism best explains the failure to improve with antibiotic therapy? <> context@']