Conjugative plasmids in Neisseria gonorrhoeae

Abstract

A conjugation system initially discovered in .beta.-lactamase-producing gonococci mobilized small non-selftransmissible R plasmids encoding .beta.-lactamase (penicillinase) production into other gonococci, Neisseria and Escherichia coli. This conjugation system was mediated by a separate self transmissible plasmid of 23.9 .times. 106 daltons, pFA2. Conjugative plasmids capable of mobilizing R plasmids were also found in nearly 8% of the non-penicillinase-producing gonococci. These were similar to pFA2 in size, buoyant density and [EcoRI, BamHI and HpaII] restriction endonuclease digest patterns but were less efficient than pFA2 in mobilization of the penicillinase plasmid pFA3. The presence of conjugative plasmids in gonococci isolated before the appearance of penicillinase-producing strains indicates that a conjugation system for plasmid transfer predated the appearance of R plasmids in gonococci.