Final answer:
To isolate Corynebacterium diphtheriae, the causative agent of diphtheria, a throat swab is typically used. Diagnosis may involve staining techniques or enriched culture media and toxin detection through PCR-based assays.
Step-by-step explanation:
The specimen used to isolate Corynebacterium diphtheriae, the causative agent of diphtheria, is a throat swab. Identification is crucial for diagnosing diphtheria, a respiratory disease marked by the presence of a pseudomembrane. A nasopharyngeal specimen can also be used during the first few weeks of infection. Diagnosis may involve using staining methods, like methylene blue stain for metachromatic granules, or culture media such as the enriched Bordet-Gengou medium. Moreover, the diphtheria toxin can be detected through PCR-based techniques and immunological tests like Elek's immunodiffusion test.