Genotypic characterization <i>Escherichia coli</i> strains from Japan producing AmpC beta-lactamase

AmpC is a class C Ambler β-lactamase that confers resistance to cephamycins. Globally reported AmpC-producing Enterobacterales are clinically important due their therapeutic restrictions and epidemiology. Between April 2021 May 2021, an outbreak of beta-lactamase-producing Escherichia coli occurred at Showa University Hospital. Because this outbreak, plasmid typing, enterobacterial repetitive intergenic consensus-polymerase chain reaction （ERIC-PCR） analysis, conjugation experiments, pulsed-field gel electrophoresis （PFGE） were performed study the molecular epidemiological characteristics these E. strains. ERIC-PCR experiments detected IncFrepB＋, IncFIA＋, IncFIB＋ multiple-replicon conjugative plasmids carrying gene （blaDHA-1）. Five eleven isolates showed same PFGE banding pattern in XbaI-digested genomic DNA, whereas remaining six strains displayed minor variants. These data highlight need for improvements infection control surveillance measures prevent spread blaDHA-1-carrying