IncX4 Plasmid-Mediated mcr-1.1 in Polymyxin-Resistant Escherichia coli from Outpatients in Santa Catarina, Southern Brazil

Abstract

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 mcr-1.1-positive polymyxin-resistant Escherichia coli isolates identified for the first time in community patients, in Santa Catarina, Southern Brazil. E. coli 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 E. coli strains, mcr-1.1 genes were carried by IncX4 plasmids, responsible for the worldwide dissemination of mcr-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 mcr-1. In conclusion, these data confirm the presence of international ST206 and ST354 carrying mcr-1.1 genes and that the IncX4 plasmids have been key vectors contributing to the endemic status of mcr-1.1-positive polymyxin-resistant E. coli in Brazil. Also, we described the first known clinical isolate with the mrc1.1 gene in Santa Catarina state, Brazil, showing that plasmid-mediated polymyxin resistance has been affecting humans earlier than has been known so far.

mcr-1 Gene in Latin America: How Is It Disseminated Among Humans, Animals, and the Environment?

“…Furthermore, the IS26 mobile element upstream to the mcr-1 gene has been also associated with IncX4 plasmid types in Brazil, but there are no other reports in Latin America (26,46) (Table 1). This Insertion Sequence (IS) plays an important role in the dissemination and evolution of the antimicrobial resistance genes on plasmids, including colistin resistance genes (1).…”

Isolation of Escherichia coli and Staphylococcus aureusin raw milk from refrigeration tanks: identification and antimicrobial resistance profiles

“…Resistance to several antibiotics may be attributed to the presence of certain genes, such as mcr-mediated colistin resistance and/ or plasmids from the incF and incX groups, among other factors (SAIDENBERG et al, 2020;ZAMPARETTE et al, 2020;CASTRO et al, 2021). These genes and plasmids have been previously detected in E. coli isolated from clinical and food samples in Brazil (SAIDENBERG et al, 2020;ZAMPARETTE et al, 2020) as well as in bovine faeces in Canada (CASTRO et al, 2021).…”

Gram-negative bacilli carrying mcr gene in Brazil: a pathogen on the rise

“…IncI2, IncHI2, and IncX4 are described as the main groups of plasmids responsible for carrying resistance genes. There are many studies describing the spread of colistin resistance related to gene variants, sites, the types of samples analyzed, the species of isolates, and the type of carrier plasmids (Table 2 ) [ 17 , 21 , 30 , 34 , 55 , 60 ].…”

“…There are many studies describing the spread of colistin resistance related to gene variants, sites, the types of samples analyzed, the species of isolates, and the type of carrier plasmids (Table 2 ) [ 17 , 21 , 30 , 34 , 55 , 60 ].…”

“…Initial reports of the presence of mcr-1 in Brazil were based on 16 samples of E. coli isolated from poultry and swine. Subsequently, the first case of clinical isolates and environmental samples carrying mcr-1 has been reported in 2016 [ 20 , 21 ]. Nowadays, there are several reports of isolates that produce MCR-1 related to nosocomial infections across the country [ 22 ].…”