R-plasmid-mediated chromosome mobilization in Bordetella pertussis.

Antibiotic-resistant and auxotrophic mutants of Bordetella pertussis were isolated. These were used as recipients for the uptake from Escherichia coli of broad-host-range R plasmids R68.45, RP1, and RP1 and RP4 carrying transposons Tn501 and Tn7 respectively. B. pertussis transconjugants from these crosses were used as donors to mobilize StrR, NalR, thr+ and gly+ chromosomal markers to B. pertussis or to B. parapertussis recipient strains. The frequency of plasmid transfer varied and depended on the donor and recipient strains used. Differences in chromosome mobilization frequencies of individual markers were observed and appeared to depend on the presence or absence of transposons Tn501 and Tn7 on the plasmid. Linkage was detected between the gly+ and NalR markers.