sentence: Interestingly , both E. cloacae T6SSs showed an additive effect in in vivo intestinal colonization , suggesting that both secretion systems are important in the adherence of E. cloacae to epithelial cells and , most importantly , in the bacterial competition of this microorganism against other bacteria found in the gut microbiota.Phylogenetically , E. cloacae T6SS-1 is related to the S. Typhi and S. Typhimurium T6SSs located on Salmonella Pathogenicity Island 6 , which are required for gut colonization and systemic infection in humanized and non humanized mice , respectively ( Libby et al ., 2010 ; Pezoa et al ., 2013 ; Sana et al ., 2016 ) .