What is the action of ChloraPrep on Gram-positive and Gram-negative bacteria; Residual activity?

• A. Excellent; Good; Little
• B. Excellent; Excellent; Little
• C. Good; Excellent; Little
• D. Good; Good; Little

Answer: (A)

ChloraPrep (chlorhexidine in alcohol) works by rapidly killing bacteria through disruption of the cell membrane after it binds to negatively charged sites on the bacterial cell wall and skin. Gram-positive organisms are highly susceptible because they lack an outer membrane, so chlorhexidine can penetrate quickly and cause rapid membrane disruption, giving excellent immediate activity. Gram-negative bacteria have an outer membrane that hinders access, so the immediate effect is still present but not as strong, described as good. As for residual activity, chlorhexidine can remain bound to skin proteins and keratin after drying, but in this context its persistent effect is described as little, meaning the lasting antimicrobial activity is limited, especially compared with Gram-positive organisms.