Which microorganism is sensitive to optochin?

Streptococcus pneumoniae is sensitive to optochin, which is a distinguishing feature of this particular microorganism. When cultured on blood agar, S. pneumoniae exhibits a zone of inhibition around an optochin disc, confirming its sensitivity. This characteristic is clinically significant because it helps to differentiate S. pneumoniae from other alpha-hemolytic streptococci, such as Streptococcus mitis and Streptococcus viridans, which are resistant to optochin.

In the context of the other microorganisms listed, Staphylococcus aureus and Enterococcus faecalis do not demonstrate sensitivity to optochin, while Neisseria meningitidis is not tested in this manner since it is typically identified through different biochemical assays and culture requirements. The ability to identify S. pneumoniae through optochin sensitivity is particularly crucial in diagnosing pneumonia, meningitis, and otitis media caused by this pathogen.