Dissemination of Resistant Escherichia coli Among Wild Birds, Rodents, Flies, and Calves on Dairy Farms

Abstract

Antimicrobial resistance (AMR) in bacteria in the livestock is a growing problem, partly due to inappropriate use of antimicrobial drugs. Antimicrobial use (AMU) occurs in Swedish dairy farming but is restricted to the treatment of sick animals based on prescription by a veterinary practitioner. Despite these strict rules, calves shedding antimicrobial resistant Enterobacteriaceae have been recorded both in dairy farms and in slaughterhouses. Yet, not much is known how these bacteria disseminate into the local environment around dairy farms. In this study, we collected samples from four animal sources (fecal samples from calves, birds and rodents, and whole flies) and two environmental sources (cow manure drains and manure pits). From the samples, Escherichia coli was isolated and antimicrobial susceptibility testing performed. A subset of isolates was whole genome sequenced to evaluate relatedness between sources and genomic determinants such as antimicrobial resistance genes (ARGs) and the presence of plasmids were assessed. We detected both ARGs, mobile genetic elements and low rates of AMR. In particular, we observed four potential instances of bacterial clonal sharing in two different animal sources. This demonstrates resistant E. coli dissemination potential within the dairy farm, between calves and scavenger animals (rodents and flies). AMR dissemination and the zoonotic AMR risk is generally low in countries with low and restricted AMU. However, we show that interspecies dissemination does occur, and in countries that have little to no AMU restrictions this risk could be under-estimated.

Core Genome Sequencing Analysis of E. coli O157:H7 Unravelling Genetic Relatedness among Strains from Cattle, Beef, and Humans in Bishoftu, Ethiopia

“…All of them carried the mdf A gene encoding for the non-specific MdfA multi-drug efflux pump [41]. This gene seems to be commonly present among E. coli isolates independent of the source of isolation [42,43].…”

Epidemiological study of antimicrobial-resistant bacteria in healthy free-ranging bantengs (Bos javanicus) and domestic cattle

“…The relationships between various factors and the prevalence of ESBLs in wildlife have been reported in various studies. These factors include high cattle densities [ 33 ], the presence of wastewater treatment plants [ 34 ], and the existence of scavenger species [ 35 ]. Potentially, the bantengs in our study might act as reservoirs hosting ARMs from multiple origins, implying that the ARMs in the population were not solely introduced by the domestic cattle.…”

Microbial Risks Caused by Livestock Excrement: Current Research Status and Prospects

“…that live with domestic animals also continuously import microorganisms from the environment and other sources into the livestock living environment, eventually allowing these microorganisms to enter the livestock excrement [ 46 , 47 , 48 , 49 ]. In addition, free-range livestock may introduce microorganisms carried by wild animals, especially potential pathogens (such as zoonotic viruses, bacteria, fungi, and parasites) [ 50 , 51 , 52 ], into livestock niches and in the long run introduce these microorganisms into the livestock excrement, resulting in the movement and enrichment of microorganisms with certain health risks into the closely related environment of domestic animals and humans, which eventually pose a threat to animal and human health.…”