Abstract
OBJECTIVES: This study describes the characterization of type 2 IncC plasmids pC-Ec20-KPC and pC-Ec2-KPC, carrying blaKPC-2 gene, from two multiresistant E. coli recovered in the University Hospital of Larissa, in 2018. METHODS: Escherichia coli, Ec-2Lar and Ec-20Lar, were recovered from rectal swabs from two patients, during the monthly surveillance cultures.
Transfer experiments by conjugation were carried out with E. coli recipients. blaKPC-carrying plasmids were characterized by S1 profiling. Isolates were typed by MLST.
Whole bacterial genome was sequenced using the Sequel platform. RESULTS: Both E. coli isolates, belonging to ST648, transferred the blaKPC-2 to E. coli A15 laboratory strain by conjugation.
Plasmid analysis revealed that the transconjugants harbored blaKPC-positive plasmids of different sizes. Analysis of plasmid sequences showed that, in both isolates, blaKPC-2 gene was carried on type 2 IncC plasmids pC-Ec20-KPC and pC-Ec2-KPC.
Both plasmids carried the ARI-B resistance island, which consisted of several resistance genes, intact and truncated copies of several mobile elements, and a 25,571-bp segment harboring coding sequences for an iron transporter. The blaKPC-2 gene was part of the transposon Tn4401a, which was bounded by direct repeats of 5 bp (TCCTT) suggesting its transposition into the IncC plasmids.
CONCLUSIONS: To our knowledge, this is the first report on complete nucleotide sequences of type 2 IncC plasmids. These findings, which hypothesize the acquisition of KPC-2-encoding transposon Tn4401a by an IncC replicon, indicate the ongoing need for molecular surveillance studies of MDR pathogens.
Additionally, they underline the increasing clinical importance of the IncC plasmid family.