Question

multiple choice question
bacteria in biofilms are __ antimicrobials that worked against them when they were free living because __.
options:

• susceptible to; the structure of the biofilm does not prevent antimicrobial penetration
• susceptible to; the structure of the biofilm enhances antimicrobial penetration
• unaffected by; they have different antibiotic susceptibilities due to a change in gene expression
• unaffected by; the structure of the biofilm completely blocks antimicrobial penetration

Explanation:

To solve this, we analyze each option:

• Option 1: Biofilm structure does prevent antimicrobial penetration, so this is wrong.
• Option 2: Biofilm structure hinders, not enhances, penetration, so wrong.
• Option 3: Bacteria in biofilms have altered gene expression (e.g., stress responses, altered metabolism) leading to different antibiotic susceptibilities compared to free - living bacteria. This matches the known behavior of biofilm - associated bacteria.
• Option 4: The biofilm structure doesn't completely block penetration (some antimicrobials can still penetrate to some extent), so wrong.

Answer:

The third option (unaffected by; they have different antibiotic susceptibilities due to a change in gene expression)