In the context of susceptibility interpretation, Broad corresponds to which set of patterns?

• A. S/R, I/R, R/R
• B. S/S, S/I, I,I
• C. S/I, I/I, S/S
• D. S/S, R/I, I/R

Answer: (B)

Broad refers to broad-spectrum activity, meaning the antibiotic would be effective against a wide range of organisms. In susceptibility interpretation, that shows up as little or no resistance across the tested agents, with results that are mostly susceptible (S) or intermediate (I) rather than resistant (R). The pattern shown here has no resistant results and includes S or I across the different agents, indicating the agent would cover a broad set of bacteria. That makes this pattern the best match for broad-spectrum activity. Patterns that include any resistant results would imply a narrower or limited effectiveness and don't fit the idea of broad.