Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/23/2015
Publication Date: 10/27/2015
Citation: Chen, C. 2015. Horizontal gene transfer and antibiotic resistance plasmids in multi-drug resistant Salmonella enterica serovars. Global Collaboration Conference on Antibiotic Resistance Mitigation and Food Safety: Science, Innovation and Strategies. p.1.
Technical Abstract: Antibiotic resistant foodborne pathogens pose serious public health concerns and increase the burden of disease treatment. Antibiotic resistance genes can reside on the bacterial chromosome or on other self-replicating DNA molecules such as plasmids. The resistance genes/DNA can be transferred into other bacteria (horizontal gene transfer) using several mechanisms such as transformation (uptake of “free” DNA), plasmid transfer via conjugation (bacterial mating) and transduction via bacteriophages. Examples will be presented on the studies of antibiotic resistance plasmids in Salmonella enterica isolates collected from the National Antimicrobial Resistance Monitoring System (NARMS). The Main focus will be on the detection, distribution, and characterization of a group of ColE1-like plasmids carrying kanamycin resistance genes (KanR plasmids) in various Salmonella serovars from the 2005 and 2010-2011 NARMS samples. The KanR plasmids were classified by their restriction patterns and plasmid structures. The ability of these small KanR plasmids to be mobilized by other large conjugative plasmids was also assessed. Eight representative KanR plasmids were tested with two of the best-studied conjugative mechanisms (F and IncP plasmids) for the transmission study. Different KanR plasmid groups showed different preference for the F or IncP-type conjugative mechanisms, and the transfer frequencies varied greatly. Plasmid transfer is currently being evaluated in biofilms, showing similar trends to those observed on agar plates. Understanding the mechanisms and preference by which the antibiotic resistance plasmids are transferred will enhance our knowledge on the transmission of antibiotic resistance plasmids and may help to devise intervention technologies to interfere or prevent the spread of resistance genes.