AUTHOR=Li Yinghui , da Silva Giarlã Cunha , Li Yanwen , Rossi Ciro C. , Fernandez Crespo Roberto , Williamson Susanna M. , Langford Paul R. , Bazzolli Denise Mara Soares , Bossé Janine T. 

TITLE=Evidence of Illegitimate Recombination Between Two Pasteurellaceae Plasmids Resulting in a Novel Multi-Resistance Replicon, pM3362MDR, in Actinobacillus pleuropneumoniae

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02489

DOI=10.3389/fmicb.2018.02489

ISSN=1664-302X

ABSTRACT=<p>Evidence of plasmids carrying the tetracycline resistance gene, <italic>tet</italic>(B), was found in the previously reported whole genome sequences of 14 United Kingdom, and 4 Brazilian, isolates of <italic>Actinobacillus pleuropneumoniae.</italic> Isolation and sequencing of selected plasmids, combined with comparative sequence analysis, indicated that the four Brazilian isolates all harbor plasmids that are nearly identical to pB1001, a plasmid previously found in <italic>Pasteurella multocida</italic> isolates from Spain. Of the United Kingdom isolates, 13/14 harbor plasmids that are (almost) identical to pTetHS016 from <italic>Haemophilus parasuis</italic>. The remaining United Kingdom isolate, MIDG3362, harbors a 12666 bp plasmid that shares extensive regions of similarity with pOV from <italic>P. multocida</italic> (which carries <italic>bla<sub>ROB-1</sub></italic>, <italic>sul2</italic>, and <italic>strAB</italic> genes), as well as with pTetHS016. The newly identified multi-resistance plasmid, pM3362MDR, appears to have arisen through illegitimate recombination of pTetHS016 into the stop codon of the truncated <italic>strB</italic> gene in a pOV-like plasmid. All of the <italic>tet</italic>(B)-carrying plasmids studied were capable of replicating in <italic>Escherichia coli</italic>, and predicted origins of replication were identified. A putative origin of transfer (<italic>oriT</italic>) sequence with similar secondary structure and a <italic>nic</italic>-site almost identical to that of RP4 was also identified in these plasmids, however, attempts to mobilize them from an RP4-encoding <italic>E. coli</italic> donor strain were not successful, indicating that specific conjugation machinery may be required.</p>