In this study we report the detection of the recently described mcr-4 gene in two human isolates of Salmonella enterica serovar Typhimurium. The strains were isolated from faecal samples of two Italian patients with gastroenteritis, collected in 2016. The identified mcr-4 genes (variant mcr-4.2) differed from the mcr-4 gene originally described in a Salmonella strain of swine origin from Italy. Salmonella species could represent a hidden reservoir for mcr genes.
Keywords: Italy; Salmonella enterica serovar Typhimurium; colistin resistance; human; mcr-4; mobile colistin resistance.