Deletions of Tn916-like transposons are implicated in tetM-mediated resistance in pathogenic Neisseria.
Using the tetM-containing conjugative transposon Tn916 as a mutagenesis tool, we identified two distinct classes of transposon insertions in the meningococcal chromosome. Class I insertions have an intact copy of Tn916 that appears to have transposed by a novel recombinational mechanism, similar to the transposition of conjugative transposons in Gram-positive bacteria. Class II insertions were characterized by deletions of Tn916 but preservation of the tetM determinant. In addition, we identified Class II Tn916-like insertions in the naturally occurring 25.2 MDa tetM-containing plasmids of both Neisseria meningitidis and Neisseria gonorrhoeae. The turncated Tn916-like insertions appeared to be present in the same site in these two plasmids; however, the deletions of the transposon were different. Plasmid sequence adjacent to the truncated transposon in the 25.2 MDa plasmids was found in a tetracycline-sensitive N. gonorrhoeae 24.5 MDa conjugative plasmid. These data suggest that the 25.2 MDa plasmids are the result of one or a series of Class II Tn916-like insertions into 24.5 MDa conjugative plasmids. Class II insertions of Tn916-like transposons are implicated in the dissemination of tetM resistance in pathogenic Neisseria.
Swartley
J S
JS
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
McAllister
C F
CF
Hajjeh
R A
RA
Heinrich
D W
DW
Stephens
D S
DS
D001483:Base Sequence; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics*; D009343:Neisseria / Q000235:genetics* / Q000472:pathogenicity; D009344:Neisseria gonorrhoeae / Q000235:genetics / Q000472:pathogenicity; D009345:Neisseria meningitidis / Q000235:genetics / Q000472:pathogenicity; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013753:Tetracycline Resistance / Q000235:genetics*
D004251:DNA Transposable Elements