FIELD: medicinal and veterinary microbiology. SUBSTANCE: plasmid p74 determining synthesis of microcin showing broad action spectrum is prepared. Method of plasmid p74 preparing involves transfer of plasmid p1 from cells Enterobacter sp. to cells E. coli C600 by mobilization of nonconjugative plasmid RSF 1010 and by insertion of transposon Tn5 determining resistance to kanamycin in natural plasmid p1. Plasmid p74 is transformed into cells E. coli M17 to obtain strain E. coli M17 (p74) showing broas spectrum of antagonistic action. As a result, strain showing antagonistic effect against pathogenic bacteria of different taxonomic groups (Escherichia coli, Salmonella, Shigella, Pseudomonas, Klebsiella, Proteus, Citobacter, Bacillus megaterium, B. pumilis) is prepared. Strain shows antagonistic activity in vitro, its harmless for laboratory animals and calves. EFFECT: enlarged spectrum of antagonistic action of strain, preparing of plasmid indicated above. 2 cl, 1 tbl
