Refrigeration of a specimen for several months may enhance the isolation of which organism?

Refrigeration of a specimen for several months can indeed enhance the isolation of Listeria monocytogenes. This organism has a unique ability to survive and even grow at low temperatures, including those typically found in refrigerated environments. The cold preservation allows Listeria to remain viable, and when the specimen is subsequently cultured, the organism can be isolated more effectively.

The other organisms listed do not share the same capacity for enhanced isolation under prolonged refrigeration. Bacillus cereus, for instance, is typically associated with foodborne illness and may not survive well in refrigerated conditions for extended periods. Corynebacterium diphtheriae, while it can survive in cold environments, does not thrive to the same extent as Listeria when refrigerated for long durations. Mycobacterium tuberculosis, known for its slower growth and specific culture requirements, is not enhanced by refrigeration and often requires specialized media and conditions for successful isolation. Thus, Listeria monocytogenes is uniquely suited to benefit from refrigeration over the others.