Vegetable-derived carbapenemase-producing high-risk Klebsiella pneumoniae ST15 and Acinetobacter baumannii ST2 clones in Japan
This study was conducted to characterize carbapenemase-producing Klebsiella pneumoniae and Acinetobacter baumannii isolated from fresh vegetables in Japan. Two K. pneumoniae (AO15, and AO22) and one A. baumannii (AO22) isolates collected from vegetables in the Higashihiroshima city, Japan and subjected to antimicrobial susceptibility testing, conjugation experiments and complete genome sequence using Illumina MiniSeq and Oxford Nanopore sequencing platforms.
The two K. pneumoniae isolates were clonal, belonging to ST15 and were detected to carry 19 different antimicrobial resistance genes, including blaNDM-1. Both the isolates carried blaNDM-1 on a self-transmissible IncFII(K):IncR plasmid of 122,804 bp in size with other antimicrobial resistance genes against aminoglycosides (aac(6')-Ib, aadA1, aph(3')-VI), β-lactams (blaCTXM-15, blaOXA-9, blaTEM-1A), fluoroquinolones (aac(6')-Ib-cr), and quinolones (qnrS1). A. baumannii AO22 carried blaOXA-66 on the chromosome, while blaOXA-72 was found as two copies on a GR2-type plasmid of 10,880 bp in size.
Interestingly, A. baumannii AO22 harbored AbaR4-like genomic resistance island (GI) of 41,665 bp carrying antimicrobial resistance genes against tetracycline [tet(B)], sulfonamides (sul2), and streptomycin (strAB). Here, we identified Japanese carbapenemase-producing Gram-negative bacterias isolated from vegetables posing a food safety issue and a public health concern. Additionally, we reported a GR2-type plasmid carrying two copies of blaOXA-72 and an AbaR4-like resistance island from a foodborne A. baumannii.