A 29-yeаr-оld pаtient with аcquired immunоdeficiency syndrоme (AIDS) is suspected of having a Cryptococcus spp. infection in the cerebrospinal fluid (CSF). A CSF specimen is collected and set up on cycloheximide agar. In addition, an India ink stain is set up. The India ink stain reveals encapsulated yeast; however, 3 weeks later, the cycloheximide agar is negative. Which one of the following statements explains this discrepancy?