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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Characterization and Interventions for Foodborne Pathogens » Research » Publications at this Location » Publication #383182

Research Project: Molecular Characterization of Foodborne Pathogen Responses to Stress

Location: Characterization and Interventions for Foodborne Pathogens

Title: Characterization of IncI1 and IncX conjugative plasmids and evaluation of their role in mobilization of different Kanamycin resistance ColE-like plasmids

item McMillan, Elizabeth
item Nguyen, Ly Huong
item Hiott, Lari
item SHARMA, POONAM - Oklahoma State University
item Jackson, Charlene
item Frye, Jonathan
item Chen, Chinyi

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/2021
Publication Date: 6/20/2021
Citation: Mcmillan, E.A., Nguyen, L.T., Hiott, L.M., Sharma, P., Jackson, C.R., Frye, J.G., Chen, C. 2021. Characterization of IncI1 and IncX conjugative plasmids and evaluation of their role in mobilization of different Kanamycin resistance ColE-like plasmids. Meeting Abstract. ASM Microbe 2021/ World Microbe Forum (virtual), June 20-24, 2021.

Interpretive Summary:

Technical Abstract: Background: Plasmid transfer plays a crucial role in the transmission of antibiotic resistance. In addition to the conjugative plasmids, some plasmids, although not self-transmissible, can be mobilized by other plasmid or chromosomally encoded transfer machineries. Small ColE-like plasmids carrying kanamycin resistance genes (KanR plasmids) were shown to possess diverse structures in their RNA I/II region and mobilization gene(s). However, the mobilization of these plasmids by different conjugative plasmids has not been systematically studied. Methods: Multidrug resistant isolates of Salmonella enterica (n=6) and Escherichia coli (n=5) were tested for conjugative plasmids carrying ß-lactam-resistance (bla) genes by the ability to convert E. coli NEB10ß to AMP-resistant via conjugation. Plasmid replicons and the bla genes present in the original isolates and the transconjugants were characterized using a PCR-based plasmid replicon typing kit (PBRT) and ARM-D ß-lactamases ID kit, respectively. Plasmid sequences of the original isolates and transconjugants were assembled from the whole genomes sequenced using Illumina MiSeq. Mobilization of different KanR plasmids by these conjugative plasmids was tested using bi- and tri-parental matings. Results: Numerous plasmid replicons were identified in this study with IncI1 being the most common in the original isolates. Four S. enterica and 3 E. coli isolates carried 2 or more plasmid replicons. One E. coli was not positive for any replicon using PBRT; only 1 of the original isolates did not carry blaCMY-2-like genes. All 6 S. enterica and 1 E. coli isolates were capable of conjugation. The resulting transconjugants from the S. enterica isolates carried plasmids of IncI1 (n=4), X1 (n=1), or both (n=1); one of these encodes blaTEM-1 instead of blaCMY-2. The conjugative plasmid derived from the E. coli isolate was unclassifiable by PBRT, but shown to be IncX4 by sequencing. IncI1 plasmids were capable of mobilizing all KanR plasmids with different mobilization gene(s). The mobilization patterns by the IncX1 and X4 plasmids are similar to that of the IncP, requiring the mobC-mobABD operon. Conclusion: Mobilization of the KanR plasmids depends on the transfer machineries encoded on the conjugative plasmid, as well as the accessory mobilization proteins and the oriT on the Col plasmid. IncI1, X1 and P plasmids encode closely related MOBp relaxases, but the mobilization patterns are different. Further in-depth study of the interaction between different conjugative and Col plasmids is warranted.