Not appropriate when describing Streptococcus pneumoniae?

Not appropriate when describing Streptococcus pneumoniae?

• A. Alpha-hemolytic
• B. Lancet-shaped diplococcus
• C. Encapsulated
• D. Bile-resistant

Answer: (D)

Streptococcus pneumoniae is classically defined by several features that help identify it in the lab: alpha-hemolysis on blood agar, lancet-shaped Gram-positive diplococci, and a polysaccharide capsule (encapsulated). An essential distinguishing property is bile solubility: the organism is lysed by bile salts, so colonies disappear or are cleared in the presence of bile. This bile solubility is what labs use to separate pneumococcus from bile-insoluble viridans streptococci. Describing it as bile-resistant would be incorrect because S. pneumoniae does not resist bile; it is affected by it and is dissolved by it. The other descriptors fit well: alpha-hemolysis indicates partial hemolysis with a greenish coloration, Lancet-shaped diplococci describe its typical microscopic form, and encapsulation is a key virulence factor detectable by methods like the Quellung reaction.

Streptococcus pneumoniae is classically defined by several features that help identify it in the lab: alpha-hemolysis on blood agar, lancet-shaped Gram-positive diplococci, and a polysaccharide capsule (encapsulated). An essential distinguishing property is bile solubility: the organism is lysed by bile salts, so colonies disappear or are cleared in the presence of bile. This bile solubility is what labs use to separate pneumococcus from bile-insoluble viridans streptococci.

Describing it as bile-resistant would be incorrect because S. pneumoniae does not resist bile; it is affected by it and is dissolved by it. The other descriptors fit well: alpha-hemolysis indicates partial hemolysis with a greenish coloration, Lancet-shaped diplococci describe its typical microscopic form, and encapsulation is a key virulence factor detectable by methods like the Quellung reaction.