Formula C21H28N2O2 | Molar mass 340.46 g/mol | |
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Microbiology optochin
Optochin (or ethylhydrocupreine hydrochloride) is a derivative of hydroquinine introduced in 1911 by Morgenroth and Levy with the intention to treat pneumococci infection. In very high dilutions inhibits the growth of representatives of all four groups of pneumococci in vitro. That is the main reason it is now used in cell culture techniques for the presumptive identification of Streptococcus pneumoniae, which is optochin-sensitive, from other alpha-hemolytic streptococci such as viridans streptococci, which are resistant.
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The growth of bacteria that are optochin-sensitive will show a zone of inhibition around an optochin disc, while the growth of bacteria that are optochin-resistant will not be affected. In vitro, an minimum inhibitory concentration (MIC) of 1:10,000,000 will affect growth of pneumococcus, and 1:500,000 is bactericidal.
Optochin test for strep pneumoniae
Resistance
Strains of Streptococcus pneumoniae have been found to be resistant to optochin in laboratory testing.