Research note: Occurrence of encoded colistin resistance in from pigs and pig farm workers in Vietnam.

WHO considers colistin as a highest priority critically important drug for human health, and occurrence of colistin-resistant bacteria in livestock is of health concern. The current study determined occurrence of colistin-resistant in pigs and workers at pig farms in Vietnam, and investigated the genetic background for resistance. Colistin-resistant were detected from pigs in 53/116 (45.7%) farms, and from workers taking care of the pigs in 21/94 (22.3%) farms. Colistin-resistant isolates showed MIC to colistin between 4-16 mg/L, they were multidrug resistant (99%) and resistance was caused by the presence of genes in 97/102 (95.1%) from pigs and in 31/34 (91.1%) isolates from humans. is considered a plasmid-encoded gene, but this was not confirmed in the current investigation. In total, one pig isolate carried both and genes, whereas and genes were not detected. Shared resistance profiles between pig and human isolates on the same farm was only observed in four farms. The study showed that commensal from pigs in Vietnam constitute a reservoir for colistin-resitant , however, further studies are needed to confirm that genes are associated with plasmids and their importance for human health.