[Beta-lactam antibiotic inactivating substance of gram negative bacilli and a new biological assay method].
D001419:Bacteria / Q000032:analysis*; D001681:Biological Assay / Q000379:methods; D002511:Cephalosporins / Q000037:antagonists & inhibitors*; D010406:Penicillins / Q000037:antagonists & inhibitors*
D002511:Cephalosporins; D010406:Penicillins