This study aims to investigate and compare the complete nucleotide sequences of the multidrug resistance plasmids pVb0267 and pVb0499, which were recovered from foodborne
Vibrio parahaemolyticus
isolates, and analyze the genetic environment of
bla
CTX–M–55
to provide insight into the dissemination mechanisms of this resistance element. Analysis of the sequences of plasmids pVb0267 (166,467 bp) and pVb0499 (192,739 bp) revealed that the backbones of these two plasmids exhibited a high degree of similarity with pR148, a recognized type 1a IncC plasmid recovered from
Aeromonas hydrophila
(99% identity). The resistance genes, found in both plasmids, included
qacH, aadB, arr2, bla
OXA–10
, aadA1, sul1, tet
(A), and
bla
CTX–M–55
, which were mostly arranged in a specific region designated ARI-A. Plasmid pVb0499 was found to possess a larger size of ARI-A than pVb0267, which lacked a
mer
determination region, a
qnr
A segment, an
aacC3
gene and several mobility-encoding genes. Comparative analysis of resistance island (RI) of these plasmids and others revealed the potential evolution route of these RI sequences. In conclusion, plasmids harboring the
bla
CTX–M–55
gene has been recovered in
Vibrio parahaemolyticus
strains of food origin. It is alarming to find that IncC plasmids harboring resistance islands are disseminating in aquatic bacterial strains. The continuous evolution of resistance genes in conjugative plasmid in aquatic bacteria could be due to bacterial adaption to aquaculture environment, where antibiotics were increasingly used.