Multiple Plasmid Vectors Mediate the Spread of in Extended-Spectrum-β-Lactamase-Producing Isolates from Retail Vegetables in China.

The plasmid-mediated fosfomycin resistance gene has been detected in from various sources but has rarely been reported in vegetables. In this study, the aim was to investigate the prevalence of and, subsequently, to characterize -positive isolates from retail vegetables. Seventeen (7.3%) -carrying strains were identified from 233 extended-spectrum-β-lactamase-producing isolates from vegetables. All 17 isolates, including six , seven , two , and two isolates, carried S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) and hybridization confirmed that the genes in 16 isolates were located on plasmids ranging in size from ∼40 kb to ∼250 kb, except one located on chromosome of All the carrying plasmids from 16 -positive isolates were successfully transferred into the recipient bacteria by transformation or conjugation. In agreement with data determined with isolates from food animals, the IncHI2/ST3 and IncN-F33:A-:B-/F33:A-:B plasmids were the main vectors of in Additionally, F24:A-:B1, IncFII-IncR, IncFII, IncR, and two untypeable plasmids were found for the first time to be vectors for in The genetic contexts of in 15 isolates differed due to insertion and/or loss of molecular modules mediated by mobile elements. However, all genes were flanked by IS, as commonly observed in other -carrying plasmids. Here, we report a high rate of detection of genes, mediated by multiple plasmid vectors, in ESBL-producing from retail vegetables. FosA3-producing could be transmitted to the human body by direct contact or consumption of vegetables, which might pose a potential threat to public health. This report provides important information on the transmission and epidemiology of among isolates from vegetables. The rate of occurrence of in ESBL-producing from retail vegetables is high, and was found to be carried by diverse plasmids. Some novel genetic contexts of and novel -carrying plasmids, including several plasmid types common in , were identified, increasing the number of known transfer vectors for the gene and reflecting the complexity of transmission in The capture of by the resident plasmid of will accelerate the spread of in , one of the most pathogenic species in clinical medicine. Considering the clinical importance of fosfomycin, and the fact that vegetables are directly consumed, the fosfomycin resistance genes present a risk of transmission to the human body through the food chain and thus pose a threat to public health.