Resistant bacteria found on pig farm in U.S.
Superbugs resistant to carbapenems were discovered by researchers from Ohio State University.
The bacteria have a transmissible gene, allowing them to pass on resistance to “critically important” last resort treatments.
Carbapenems aren’t used in livestock farming, though bacteria resistant to the antibiotics was detected on European farms in 2014, which led the industry group Responsible Use of Medicines in Agriculture (RUMA) to claim that resistance must have developed from human medicine (resistant bacteria have been found in hospitals).
However, the Ohio researchers said a related antibiotic approved for farm use in the US might have led to the development of resistance.
Although farmers don’t use carbapenems, they do use other beta-lactams - the class of antibiotics to which these belong.
Carbapenem-resistant bacteria have been found in waste water and soil, and environmental sources of antibiotic resistance (for example, drugs passed through humans and released into the environment) remain little-studied, and poorly understood.
Researchers found resistant bacteria in piglets, but not in slaughter-ready pigs on a 1,500-sow farm.
They hypothesised that the resistant bacteria have developed as a result of the use of beta-lactam antibiotic ceftiofur, which is used on newborn piglets and males at castration.
However, when pigs are sent for finishing the resistant bacteria must compete with other microbes, which could be why they didn’t find it in older pigs. ■