Ricerc@Sapienza

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. © 2018, European Centre for Disease Prevention and Control (ECDC). All rights reserved.

Background and aim: Plasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes (mcr-1 to mcr-5, and variants) in Enterobacteriaceae was developed for surveillance or research purposes. Methods: We designed four new primer pairs to amplify mcr-1, mcr-2, mcr-3 and mcr-4 gene products and used the originally described primers for mcr-5 to obtain a stepwise separation of ca 200 bp between ampli-cons.

Objectives In this study we compared the recently described mcr-4-positive Salmonella enterica monophasic variant, isolated in 2016 in two Italian patients affected by gastroenteritis, with the first mcr-4-positive Salmonella isolate identified in 2013 in a pig at slaughter in Italy. Methods WGS of the two Salmonella isolates of human origin was performed using a MiSeq instrument (Illumina).