Optochin-resistant Variants of Streptococcus Pneumoniae

Diagn Microbiol Infect Dis. Jan-Feb 1990;13(1):63-6. doi: 10.1016/0732-8893(90)90056-2.


Ten Streptococcus pneumoniae clinical isolates, possessing physiologically typical pneumococcal characteristics, showed optochin-susceptible and optochin-resistant colonies around the optochin disk, when tested for optochin susceptibility. Equivocal optochin disk test results should be confirmed by bile solubility, agglutination tests, or both.

MeSH terms

  • Agglutination Tests
  • Bile / microbiology
  • Drug Resistance, Microbial
  • Humans
  • Quinine / analogs & derivatives*
  • Quinine / pharmacology
  • Solubility
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / metabolism


  • ethylhydrocupreine
  • Quinine