Optochin (or ethylhydrocupreine hydrochloride) is a derivative of quinine introduced in 1911 by Morgenroth and Levy with the intention to treat pneumococci infection.[1] In very high dilutions, it inhibits the growth of representatives of all four groups of pneumococci in vitro. That is the main reason it is now used in bacteriology for the differentiation of Streptococcus pneumoniae, which is optochin-sensitive, from the other, resistant alpha-hemolytic streptococci, sometimes called the viridans streptococci because of the green colouration on blood agar around colonies.

Optochin
Names
IUPAC name
(4β,8α,9R)-6'-Ethoxy-10,11-dihydrocinchonan-9-ol
Other names
Ethylhydrocupreine
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.007.577 Edit this at Wikidata
MeSH Optochin
UNII
  • InChI=1S/C21H28N2O2/c1-3-14-13-23-10-8-15(14)11-20(23)21(24)17-7-9-22-19-6-5-16(25-4-2)12-18(17)19/h5-7,9,12,14-15,20-21,24H,3-4,8,10-11,13H2,1-2H3/t14-,15-,20-,21+/m0/s1 ☒N
    Key: SUWZHLCNFQWNPE-LATRNWQMSA-N ☒N
  • InChI=1/C21H28N2O2/c1-3-14-13-23-10-8-15(14)11-20(23)21(24)17-7-9-22-19-6-5-16(25-4-2)12-18(17)19/h5-7,9,12,14-15,20-21,24H,3-4,8,10-11,13H2,1-2H3/t14-,15-,20-,21+/m0/s1
    Key: SUWZHLCNFQWNPE-LATRNWQMBV
  • CC[C@H]1CN2CC[C@H]1C[C@H]2[C@@H](c3ccnc4c3cc(cc4)OCC)O
Properties
C21H28N2O2
Molar mass 340.46 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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 resistant to optochin will not be affected. In vitro, a minimum inhibitory concentration (MIC) of 1:10,000,000 will inhibit the growth of pneumococci, and 1:500,000 is bactericidal.[2]

Resistance

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For decades, Streptococcus pneumoniae has been considered susceptible to optochin; but some strains have been found to be resistant to optochin in laboratory testing. This is notable because the emergence of optochin-resistant strains would invalidate the distinguishing test described above.[3]

See also

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References

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  1. ^ Moore HF (1915). "The Action of Ethylhydrocuprein (Optochin) on Type Strains of Pneumococci in Vitro and in Vivo, and on Some Other Microorganisms in Vitro". J. Exp. Med. 22 (3): 269–85. doi:10.1084/jem.22.3.269. PMC 2125335. PMID 19867915.
  2. ^ "Ethylhydrocupreine".
  3. ^ Pikis A, Campos JM, Rodriguez WJ, Keith JM (2001), "Optochin resistance in Streptococcus pneumoniae: mechanism, significance, and clinical implications", Journal of Infectious Diseases, 184 (5): 582–590, doi:10.1086/322803, JSTOR 30137322, PMID 11474432