S. pneumoniae
IC50: 25.75 nM ( Plasmodium falciparum )
ggTas2r1, ggTas2r2 and ggTas2r7

The mutation rate to Ethylhydrocupreine (Optochin) resistance is estimated using fluctuation analysis in three capsulated S. pneumoniae strains ( S. pneumoniae D39 NCTC 7466, S. pneumoniae R6 ATCC BAA-255 and S. pneumoniae ATCC 49619). The exposure to subinhibitory concentrations of penicillin increased the mutation rate (expressed as mutation per cell division) to Ethylhydrocupreine (Optochin) resistance between 2.1- and 3.1-fold for all three strains studied.

The injection of 1 cc. of a 24 hour dextrose blood broth culture of virulent Type I pneumococci into the right pleural cavity of guinea pigs produces acute suppurative pleuritis on both sides associated with suppurative pericarditis. The injection of 1 cc. of 1:500 solutions of Ethylhydrocupreine hydrochloride into each pleural cavity of guinea pigs at varying intervals up to 24 hours after pleural infection has usually shown a marked curative influence. Similar results are observed with dogs.