Loeffler's medium is used as a primary isolation medium for which organism?

Loeffler's medium is used as a primary isolation medium for which organism?

• A. Corynebacterium diphtheriae
• B. Listeria monocytogenes
• C. Bordetella pertussis
• D. Staphylococcus aureus

Answer: (A)

The main idea is that Loeffler's medium serves as an enrichment step that supports the growth of Corynebacterium diphtheriae and enhances the visualization of its distinctive metachromatic (volutin) granules, which are diagnostic features. In practice, throat specimens are plated onto this medium to allow C. diphtheriae to grow well and form cells containing these characteristic granules, which can be seen with Albert’s stain. This makes it a useful primary isolation medium specifically for C. diphtheriae. Other organisms listed—Bordetella pertussis, Listeria monocytogenes, and Staphylococcus aureus—do not rely on Loeffler’s medium for primary isolation or for showing metachromatic granules, and they are typically identified using different media and approaches.

The main idea is that Loeffler's medium serves as an enrichment step that supports the growth of Corynebacterium diphtheriae and enhances the visualization of its distinctive metachromatic (volutin) granules, which are diagnostic features. In practice, throat specimens are plated onto this medium to allow C. diphtheriae to grow well and form cells containing these characteristic granules, which can be seen with Albert’s stain. This makes it a useful primary isolation medium specifically for C. diphtheriae. Other organisms listed—Bordetella pertussis, Listeria monocytogenes, and Staphylococcus aureus—do not rely on Loeffler’s medium for primary isolation or for showing metachromatic granules, and they are typically identified using different media and approaches.