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Title: Mobilization properties of small ColE1-like plasmids carrying kanamycin resistance gene isolated from Salmonella enterica serotypes

item Chen, Chinyi
item Nguyen, Ly Huong

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/23/2015
Publication Date: 5/30/2015
Citation: Chen, C., Nguyen, L.T. 2015. Mobilization properties of small ColE1-like plasmids carrying kanamycin resistance gene isolated from Salmonella enterica serotypes. Meeting Abstract. meeting abstract.

Interpretive Summary:

Technical Abstract: Background: Previously we isolated and characterized various groups of small kanamycin resistance (KanR) ColE1-like plasmids from different serotypes of Salmonella enterica isolates. These plasmids all carried the aph(3)-I gene encoding the aminoglycoside phosphotransferase responsible for the kanamycin resistance. They can be categorized into different groups based on their replication region, IS elements, and mobilization region. Most of these plasmid groups (groups B, C3, X, and Y/Y2/Y3) possessed the mobC-mobABD mobilization operon; group A plasmids possessed the single mobA gene; while group C carried no known mobilization gene, but possessed the origin of transfer (oriT). Materials: E. coli strains carrying representative plasmids from each of the eight groups and subgroups (A, B, C, C3, X, Y/Y2/Y3) were tested for their ability to mobilize the KanR plasmids by the conjugal transfer (tra) genes of F and IncP plasmids in either bi-parental or tri-parental (with helper strains) mating experiments. Results: Group A plasmid, carrying the single mobA gene, could only be mobilized by F plasmid in cis inefficiently (less than 10E-5); it was unable to be mobilized by either F or IncP tra genes via tri-parental mating. Conjugal transfer genes from IncP-derivatives could mobilize group B, Y/Y2/Y3 plasmids with high efficiencies (approx. 10 (-2)) via either bi-parental or tri-parental matings; however, tra genes on F plasmid (in NEB5alpha) could only mobilize these plasmids in cis rather inefficiently. Plasmids C3 and X were efficiently mobilized by either IncP or F in all situations. Plasmid C, although did not possess known mob genes, could be very efficiently mobilized by tra genes from F plasmids in cis or in trans, but not by IncP. Bi-parental mating methods worked for F tra genes with all KanR plasmid groups and for IncP plasmids with most plasmids with the exception of groups A and C. Conclusion: The difference in the mobilization properties of these KanR plasmids by various tra genes could have implication on their transmission and spread among Salmonella strains carrying different large conjugal transfer plasmids. The efficient transfer of plasmid groups B, C3, X, Y/Y2 mediated by both IncP and F tra genes could potentially facilitate the transfer of antibiotic resistance genes on these plasmid backbones into naive strains.