Objectives: A small resistance plasmid of Mannheimia varigena was analysed with regard to its gene organization and the development of a multiresistance gene cluster.
Materials and methods: The 5621 bp plasmid pMVSCS1 was transformed into Escherichia coli JM107, cloned and sequenced completely.
Results: Three intact resistance genes, sulII, catAIII and strA, a truncated strB gene and a novel replication gene were identified. A potential recombination site for the integration of catAIII in the spacer region between sulII and strA was identified.
Conclusion: The physical linkage of the plasmid-borne resistance genes organized in a cluster would facilitate the spread of the different resistance genes by co-selection, even in the absence of a direct selective pressure.