Researchers have uncovered the carbapenem-resistance gene bla IMP-27 at a pig farm in the US, NBC News reports.
"It is an extremely rare gene. How it got on this farm, we don't know," senior author Thomas Wittum from Ohio State University tells NBC.
As he and his colleagues reported in Antimicrobial Agents and Chemotherapy earlier this week, they collected environmental and fecal samples from the 1,500-sow farm during four visits over the course of five months in 2015. In this time, they detected 18 bacterial isolates harboring the bla IMP-27 gene on a plasmid, and these isolates included multiple bacteria types like Escherichia coli, Proteus mirabilis, and Enterobacteriaceae species. This, NBC notes, "suggests the bacteria have been passing the gene around."
As carbapenem is considered an antibiotic of last resort, the presence of resistance genes in livestock is worrisome, it adds. Bacteria harboring them could contaminate meat or be transmitted to people handling raw meat. Also of concern, NBC says, is that this pig farm has been run as a closed herd since the 1960s and the pigs were never treated with carbapenem, so there's uncertainty as to how this resistance gene arrived there. The researchers suspect that it might have come in on equipment, supplies, or people, NBC News adds.