Penicillin-resistant pneumococci in London.
D006801:Humans; D007223:Infant; D008131:London; D008875:Middle Aged; D010400:Penicillin G / Q000494:pharmacology*; D010403:Penicillin Resistance; D013296:Streptococcus pneumoniae / Q000187:drug effects*
D010400:Penicillin G