Elevated detection rates of the
blaCTX-M-55 gene in animals have been reported as a result of antibiotic misuse in clinics. To investigate the horizontal transfer mechanism of
blaCTX-M-55 and its associated mobile genetic elements (MGEs), we isolated 318 nonrepetitive strains of
[...] Read more.
Elevated detection rates of the
blaCTX-M-55 gene in animals have been reported as a result of antibiotic misuse in clinics. To investigate the horizontal transfer mechanism of
blaCTX-M-55 and its associated mobile genetic elements (MGEs), we isolated 318 nonrepetitive strains of
Escherichia coli (
E. coli) from bovine samples in Xinjiang and Gansu provinces, China. All
E. coli strains were screened for the
CTX-M-55 gene using PCR. The complete genomic data were sequenced using the PacBio triplet sequencing platform and corrected using the Illumina data platform. The genetic environment of the plasmids carrying the resistance
blaCTX-M-55 gene was mapped using the software Easyfig2.2.3 for comparison. The results showed that all
blaCTX-M-55-positive strains were resistant to multiple antibiotics. Five strains of
Escherichia coli carry the
blaCTX-M-55 gene, which is adjacent to other resistance genes and is located on the IncHI2-type plasmid. Four of the five
blaCTX-M-55-harbor strains carried translocatable units (TUs). All the donor bacteria carrying the
blaCTX-M-55 genes could transfer horizontally to the recipient (
E. coli J53 Azr). This study demonstrates that the transmission of
blaCTX-M-55 is localized on IS
26-flanked composite transposons. The cotransmission and prevalence of
blaCTX-M-55 with other MDR resistance genes on epidemic plasmids require enhanced monitoring and control.
Full article
