A patient attends clinic exhibiting nuchal rigidity, headach…

A patient attends clinic exhibiting nuchal rigidity, headache, and nausea. Your medical team orders a microscopic investigation of the cerebrospinal fluid removed from the meningeal space. The lab reports the presence of bacteria.  You suspect the causative agent is?

The six year-old sister of a Diptheria patient has her throa…

The six year-old sister of a Diptheria patient has her throat swabbed and cultured as a precautionary measure. Her cultures reveal the presence of a Gram-positive, club-shapped bacillus that possesses cytoplasmic granules that exhibit metachromatic staining. What is the MOST PLAUSIBLE reason the sister does not suffer from Diptheria but her brother does?