What is a residual antimicrobial effect of CHG on intact skin?

• A. It can have residual antimicrobial effect on intact skin
• B. It has no residual effect
• C. It only works on open wounds
• D. It causes persistent skin irritation

Answer: (A)

Residual antimicrobial effect is about CHG continuing to work after it’s applied. Chlorhexidine has substantivity on the skin, meaning it binds to keratin and other skin components and remains active for hours after drying. This binding lets CHG continue suppressing microbes on intact skin, not just in wounds, which is why it can have a residual antimicrobial effect even when the skin isn’t injured. The idea that there’s no residual effect isn’t accurate for CHG, since its lasting activity is a key feature. It’s also not limited to open wounds, and while CHG can cause irritation in some people, that side effect isn’t about its antimicrobial persistence.