A newly published report by researchers from Washington State University in the USA suggests that urine from cattle treated with the antibiotic ceftiofur may select for E. coli strains in soil that are resistant to cephalosporin antimicrobials.
The researchers added urine containing ceftiofur metabolites to mixtures of soil and bovine faeces and incubated them at 23oC and 4oC for various periods. They found that the metabolites broke down quickly at the higher temperature but persisted for up to 23 days at 4oC, creating an advantage for resistant E. coli strains in the soil and allowing them to survive for about two months. It was also demonstrated that the resistant bacteria were then readily able to colonise calves via contaminated bedding.
The report is published in the journal PLoS ONE and can be found here.