Salmonella enterica mcr-1 Positive from Food in Brazil: Detection and Characterization

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

“…As in other countries, the colistin was extensively used in Brazil as a growth promoter for many years. In 2016, the government published restrictions on the use of colistin in animal production (1,26), which came into force in 2018. However, the use of colistin to treat or prevent infections in veterinary medicine including animal productions is still allowed.…”

“…Although the mobility and dissemination of the mcr-1 gene are associated with ISApl1 and the pap2 gene in most plasmid types (43), the genetic context of the IncX4 plasmid type, in Latin America, is different. This context is characterized by lacking the ISApl1, but it preserves the pap2 sequence and a hypothetical protein (hp) around the mcr-1 gene (26,44). What would be the explanation for that?…”

“…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).…”

Colistin-resistant Escherichia coli belonging to different sequence types: genetic characterization of isolates responsible for colonization, community- and healthcare-acquired infections

“…Up to now, the mcr-1 gene is the most frequent plasmid-mediated colistin-resistance gene reported in Brazil 26 , 27 . It has been described in Salmonella enterica isolated from poultry meat 21 , from food 27 , and in E. coli from cattle and humans 28 , 29 and Klebsiella pneumoniae from humans 29 .…”

Prevalence of avian-origin mcr-1–positive Escherichia coli with a potential risk to humans in Tai'an, China

“…Plasmid transferability was evaluated by conjugation experiments using E. coli J53 (J53AZR). Each mcr-1 –positive isolate was incubated with E. coli J53 on a cellulose membrane in a Luria–Bertani agar plate ( Rau et al., 2020 ). After incubation at 37°C for 24 h, POL-resistant transconjugants were selected on Luria–Bertani agar plates containing sodium azide (100 μg/mL) and POL (0.5 μg/mL).…”