Transfer frequency of various 25.2 Mdal tetracycline resistance plasmids in Neisseria gonorrhoeae

We examined ten Neisseria gonorrhoeae strains, all of which carried the tetracycline resistant 25.2 Mdal plasmid, for their ability to act as donors in conjugation. All strains transferred the 25.2 Mdal plasmid and tetracycline resistance to the recipient N. gonorrhoeae strain F62 at a frequency that ranged from 10(-2) to 10(-7) per recipient. The four strains carrying the beta-lactamase plasmid and the 25.2 Mdal plasmid transferred the beta-lactamase plasmid at a frequency of 10(-6) to 10(-8) per recipient. The results indicate that most of the N. gonorrhoeae strains carrying the 25.2 Mdal plasmid can act as donors of this plasmid and can also mobilize the transfer of the 3.2 Mdal plasmid and the 4.4 Mdal plasmid to recipient strains.