Conjugative plasmids in Bordetella avium.

Three of five antibiotic-resistant plasmids isolated from virulent strains of Bordetella avium were found to be conjugative. A physical and genetic map of one of these plasmids, the 51.5-kb plasmid p4093, revealed that the area of p4093 responsible for streptomycin and tetracycline resistance was located in a region consisting of a cluster of restriction enzyme recognition sites, whereas the remainder of p4093 contained relatively few restriction sites. Additionally, the genes involved in the conjugative ability of p4093 were clustered in at least two widely separated regions of the plasmid.