Isolation of Extended‐Spectrum β‐Lactamase‐Producing Atlantibacter Hermannii VT10‐S Harboring a Transferrable IncFIB Plasmid Encoding bla CTX‐M‐27 From Imported Dried Foods

Antimicrobial resistance is a public health threat and the horizontal transfer of plasmids harboring antimicrobial resistance genes is a concern. This study aimed to determine the prevalence of plasmid‐mediated cefotaxime (CTX) and meropenem (MEM)‐resistant bacteria in dried foods imported to Japan from Southeast Asia. A total of 68 imported dried foods were purchased and mixed with buffered peptone water. After culturing in the mixing medium, the bacterial broth was spread on CHROMagar ECC containing CTX or MEM. Typical Enterobacterales colonies were selected, and antimicrobial susceptibility was determined using the disc diffusion method. Isolated colonies showing CTX or MEM antimicrobial resistance were subjected to DNA extraction using the boiling method, and bacterial species were identified using 16S rRNA sequencing. Multiplex PCR was conducted to detect genes encoding extended‐spectrum β‐lactamase (ESBL) and AmpC β‐lactamase enzymes. Whole‐genome sequencing indicated the complete genome of the ESBL‐producing strain. Seven CTX‐resistant strains of Enterobacter , Atlantibacter, Stenotrophomonas , and Pseudomonas; and three strains of Enterobacter and Stenotrophomonas MEM‐resistant bacteria were isolated. After antimicrobial susceptibility testing, a CTX‐resistant strain of Atlantibacter hermannii , VT10‐S, was identified as an ESBL producer. The total genome size of A. hermannii VT10‐S was 4,423,010 bp; it harbored a 97,668 bp IncFIB plasmid encoding bla CTX‐M‐27 . Conjugation assays indicated that the IncFIB plasmid could be transferred to Escherichia coli isolated from humans. Humans may harbor ESBL‐producing E. coli from the consumption of food imported from Southeast Asia.