A hospital reports that 18% of the 200 Enterococcus faecalis isolates from wound infections are resistant to vancomycin. After introducing a new antibiotic stewardship program, the resistance percentage drops to 9%. Calculate the number of resistant isolates before and after the program.

Step-by-step solution

1. Calculate pre‑program resistance: $200\times 18$ isolates.
2. Calculate post‑program resistance: $200\times 9$ isolates.
3. State the results: 36 isolates before, 18 isolates after.

Concept tested: Calculating antibiotic resistance frequencies

Published 20 September 2026 · How this solution was prepared and checked