Optochin sensitivity test
From IDWiki
- A test applied to alpha-hemolytic streptococci in order to presumptively identify Streptococcus pneumoniae, which is susceptible to optochin (although not all strains are susceptible)
- Apply an optochin or P disc to an SBA plate with freshly-streaked inoculum, then incubate at 35-37°C with 5% CO2 for 18 to 24 hours
- Measure the zone of inhibition
- Using a standard 6 mm disc, a zone of 14 mm or more indicates susceptibility and suggests Streptococcus pneumoniae
- Any zone of inhibition is uninterpretable, and should be followed by a bile solubility test
