Why are biofilms clinically important in infections and antibiotic resistance?

• A. Biofilms promote rapid clearance of infections.
• B. Biofilms shield bacteria from antibiotics and immune responses, enabling persistent infections and transfer of resistance genes.
• C. Biofilms form only on medical devices and have no clinical impact.
• D. Biofilms decrease genetic exchange.

Answer: (B)

Biofilms are structured communities of microbes embedded in a self-produced matrix that adheres to surfaces. They’re clinically important because this matrix and the close-knit community protect bacteria from antibiotics and immune defenses, allowing infections to persist and become chronic. Inside a biofilm, there are nutrient and oxygen gradients, and many cells enter slow-growing or dormant states, making antibiotics that target rapidly dividing cells less effective. The dense, protected environment also facilitates horizontal gene transfer, so resistance genes can spread more readily among bacteria in the biofilm. Biofilms commonly form on tissues, medical devices, and implants, which is why infections associated with catheters, prosthetics, and chronic wounds are often difficult to eradicate and prone to recurrence.

Other statements miss the mark because biofilms do not promote rapid clearance, they do have a meaningful clinical impact beyond devices, and they can enhance genetic exchange rather than decrease it.