antipneumococcic

an·ti·pneu·mo·coc·cic

(an'tē-nū'mō-kok'sik),
Destructive to, or repressing the growth of, the pneumococcus (for example, penicillin).

antipneumococcic

(1) A term of waning use for an agent that kills Streptococcus pneumonia. 
(2) A near-extinct adjective pertaining to anything that has a antipneumococcal effect.