Final answer:
In antiviral susceptibility testing, using an overly large inoculum would result in the isolate appearing resistant because an abundance of bacteria could overbear the effects of the antibiotic.
Step-by-step explanation:
When performing antiviral susceptibility testing, a standard inoculum must be used to ensure accurate results. If the inoculum quantity is too large, then the isolate will appear resistant. This is because excess bacteria may overwhelm the antibiotic, making it difficult for the drug to inhibit bacterial growth effectively, which would cause the zone of inhibition to be smaller or nonexistent. A properly standardized inoculum is crucial for reliable susceptibility testing results, as the interpretation of the Kirby-Bauer disk diffusion assay relies on the comparison of zone sizes to a standardized chart to determine if a bacterial pathogen is susceptible or resistant to antibiotics.