IncHI2 Plasmids Are the Key Vectors Responsible for oqxAB Transmission among Salmonella Species

This study reported and analyzed the complete sequences of two oqxAB-bearing IncHI2 plasmids harbored by a clinical Salmonella enterica serovar Typhimurium strain and an S. Indiana strain of animal origin, respectively. In particular, pA3T recovered from S. Indiana comprised the resistance determinants oqxAB, aac(6') Ib-cr, fosA3, and bla(CTX-M-14). Further genetic screening of 63 oqxAB-positive Salmonella isolates revealed that the majority carried IncHI2 plasmids, confirming that such plasmids play a pivotal role in dissemination of oqxAB in Salmonella spp.