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.