Molecular characterization of two beta-lactamase-specifying plasmids isolated from Neisseria gonorrhoeae

Abstract

The molecular nature of 2 distinct gonococcal R plasmids, 4.4 .times. 106 and 3.2 .times. 106 daltons, encoding .beta.-lactamase activity were examined. Both plasmids contained about 40% of the transposable ampicillin resistance sequence Tn2. DNA-RNA polynucleotide sequence studies showed that the 2 gonococcal plasmids share about 70% of their sequences and are closely related to RSF0885, a 4.1 .times. 106-dalton plasmid found in a .beta.-lactamase-producing strain of Haemophilus influenzae. All 3 of these R plasmids possess a GTC content of 0.40-0.41 mol fraction and are present as multicopy gene pools in their bacterial hosts.