Which cell is responsible for cleaning wounds of microorganisms?

The patient presents to the emergency department (ED) after being bitten by a friend’s dog with two puncture marks and an abrasion. Prior to dressing the wound, the nurse uses which substance to clean the wound?

A nurse is assigned to a 75-year-old patient with head trauma secondary to falling down the stairs at home. The patient is stable initially, complaining of headache and some dizziness, but no focal neurologic signs. That evening, the patient acutely becomes altered and rapidly loses consciousness. Which of the following most likely explains this patient’s condition?