Attempts to obtain gram-negative rods from staphylocci treated with penicillin.
D006090:Gram-Negative Bacteria; D010406:Penicillins / Q000494:pharmacology*; D013210:Staphylococcus / Q000494:pharmacology*
D010406:Penicillins
PENICILLIN/pharmacology; STAPHYLOCOCCUS/pharmacology