Conclusion
We report a novel clinical S. Virchow monophasic variant (Salmonella 6,7,14 :r:-) resulting in an infection in the knee joint of a 4-year-old girl. Replacement of the fljAB operon by a cassette from E. coli leads to the lack of phase-2 flagellar antigens in Salmonella 6,7,14:r:-. CRISPR typing and cgMLST revealed that the S. Virchow monophasic variant isolates (YZU1797 and YZU1798) were closely related to the previously reported human isolate from China, S. Virchow BCW_2814. Compared with the 16 published S. Virchow genomes, both strains obtained a unique ~43kb SGI-2 fragment, including cmlA9 ,sul1 , drfA1 , and tetA(G) genes, providing multidrug resistance to chloramphenicol, tetracycline, trimethoprim, and sulfamethoxazole. Therefore, with the emerging of the MDR S.Virchow monophasic variant causing human salmonellosis, surveillance ofSalmonella infections in human is recommended.