D-Streptamine, O-2-deoxy-2--(methylamino)-alpha-L-glucopyranosyl-(1-2)-O-5-deoxy-3-C-(hydroxymethyl)-alpha-L-lyxofuranosyl-(1-4)-N,N'-bis(aminoiminomethyl)-, sulfate (2:3) (salt), mixt. with polymyxin B sulfate