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

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

Answer: (A)

When evaluating skin prep agents, two properties matter: how strongly they kill bacteria right away (action) and how long their effect lasts after the prep has dried (residual activity). Betadine (povidone-iodine) and DuraPrep (chlorhexidine-based) are both broad-spectrum, fast-acting antiseptics, but their activity tends to be higher against Gram-positive organisms than against Gram-negative ones because Gram-positive bacteria have simpler cell walls and no outer membrane to hinder antiseptics.

So, the action is excellent against Gram-positive bacteria, while it is still good against Gram-negative bacteria because the outer membrane of Gram-negatives offers some protection. For residual activity, chlorhexidine-based products like DuraPrep tend to leave a persistent effect on skin, and povidone-iodine also provides continued activity after drying, though typically not as long-lasting; overall, the residual activity is rated as good.

That alignment—excellent action on Gram-positive, good on Gram-negative, and good residual activity—matches the correct option.