IncX4 Plasmid-Mediated in Polymyxin-Resistant from Outpatients in Santa Catarina, Southern Brazil.

Plasmid-mediated polymyxin resistance has become a global health concern, not only because its dissemination has occurred drastically but also because it has begun to be reported in multidrug-resistant (MDR) pathogens. We hereby report microbiological and genomic characteristics of two -positive polymyxin-resistant isolates identified for the first time in community patients, in Santa Catarina, Southern Brazil. strains belonging to ST206 and ST354 and the resistome analysis revealed the presence of clinically important genes responsible for MDR profile. Interestingly, in both polymyxin-resistant strains, genes were carried by IncX4 plasmids, responsible for the worldwide dissemination of type genes. In this regard, plasmid backbones were almost identical to the first IncX4 plasmid reported in Brazil and sharing more than 99.9% identity to IncX4 plasmids from China, also lacking the ISApl1 insertion sequence upstream of . In conclusion, these data confirm the presence of international ST206 and ST354 carrying genes and that the IncX4 plasmids have been key vectors contributing to the endemic status of -positive polymyxin-resistant in Brazil. Also, we described the first known clinical isolate with the gene in Santa Catarina state, Brazil, showing that plasmid-mediated polymyxin resistance has been affecting humans earlier than has been known so far.