{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 424978166 | ImageFile=Optochin.png | ImageClass = skin-invert-image | ImageSize=180px | IUPACName=(4β,8α,9''R'')-6'-Ethoxy-10,11-dihydrocinchonan-9-ol | OtherNames=Ethylhydrocupreine |Section1= {{Chembox Identifiers | CASNo_Ref = {{cascite|correct|??}} | CASNo=522-60-1 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 4W030VS2OG | PubChem=71542 | ChEMBL_Ref = {{ebicite|changed|EBI}} | ChEMBL = 534999 | MeSHName=Optochin | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 79283 | ChEBI_Ref = {{ebicite|changed|EBI}} | ChEBI = 86455 | SMILES = CC[C@H]1CN2CC[C@H]1C[C@H]2[C@@H](c3ccnc4c3cc(cc4)OCC)O | 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 | InChIKey = SUWZHLCNFQWNPE-LATRNWQMBV | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 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 | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = SUWZHLCNFQWNPE-LATRNWQMSA-N }} |Section2= {{Chembox Properties | Formula=C<sub>21</sub>H<sub>28</sub>N<sub>2</sub>O<sub>2</sub> | MolarMass=340.46 g/mol | Appearance= | Density= | MeltingPt= | BoilingPt= | Solubility= }} |Section3= {{Chembox Hazards | MainHazards= | FlashPt= | AutoignitionPt= }} }}
'''Optochin''' (or '''ethylhydrocupreine hydrochloride''') is a derivative of quinine introduced in 1911 by Morgenroth and Levy with the intention to treat pneumococci infection.<ref>{{cite journal | pmc = 2125335 | pmid=19867915 | volume=22 | year=1915 | journal=J. Exp. Med. | pages=269–85 | author=Moore HF | title=The Action of Ethylhydrocuprein (Optochin) on Type Strains of Pneumococci in Vitro and in Vivo, and on Some Other Microorganisms in Vitro | issue=3 | doi=10.1084/jem.22.3.269}}</ref> 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.
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.<ref>{{cite web | url=http://chestofbooks.com/health/materia-medica-drugs/Pharmacology-Therapeutics-Prescription-Writing/Ethylhydrocupreine.html | title=Ethylhydrocupreine }}</ref>
==Resistance== 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.<ref>{{citation |title=Optochin resistance in Streptococcus pneumoniae: mechanism, significance, and clinical implications |journal=Journal of Infectious Diseases |volume=184 |issue=5 |pages=582–590 |vauthors=Pikis A, Campos JM, Rodriguez WJ, Keith JM |year=2001 |pmid=11474432 |doi=10.1086/322803 |jstor=30137322|doi-access=free }}</ref>
== See also == * Quinine
==References== {{reflist}} {{Clinical microbiology techniques}} Category:Bacteriology Category:Quinolines Category:Quinuclidines Category:Phenol ethers Category:Secondary alcohols Category:Ethoxy compounds