Prevalence and trend analysis of antimicrobial resistance in clinical Escherichia coli isolates collected from diseased pigs in the USA between 2006 and 2016

Abstract

Antimicrobial resistance (AMR) is an emerging threat to both human and animal health. Antimicrobial use and resistance in food animal production, including swine, has received increased scrutiny as a source of resistant foodborne pathogens. Continuous surveillance of AMR in bacterial isolates of swine origin can guide in conservation of antimicrobials used in both human and swine medicine. The objective of this study was to evaluate the prevalence and trends of the phenotypic AMR in Escherichia coli of swine origin isolated from clinical samples at the Minnesota Veterinary Diagnostic laboratory between 2006 and 2016. The prevalence of resistance to ampicillin, tetracyclines and sulphadimethoxine remained greater than 50% throughout the period. There was a drastic change in enrofloxacin resistance, increasing from less than 1% to more than 20% between 2006 and 2016 (annual relative increase of 57% between 2006 and 2013 and 16% between 2013 and 2016). The prevalence of resistance to other antimicrobials remained constant (ceftiofur, oxytetracycline and chlortetracycline) or changed significantly (annual relative changes of less than 10%) for at least some time‐period between 2006 and 2016 (ampicillin, florfenicol, gentamicin, neomycin, sulphadimethoxine, trimethoprim‐sulphamethoxazole and spectinomycin). Rarefaction analysis revealed an increase in the number of unique combinations of AMRs per year. Network analysis was performed by estimating and plotting partial correlations between minimum inhibitory concentrations (MICs) of various antimicrobials. An increase in strength of these networks was observed, particularly in networks created after 2010, which can be indicative of increased multiple AMR in these isolates. These results provide valuable insight into the trends in AMR in E. coli of swine origin in the USA and act as supplementary information to the existing active AMR surveillance systems.

Antioxidant Activity of Flavonoids in LPS-Treated IPEC-J2 Porcine Intestinal Epithelial Cells and Their Antibacterial Effect against Bacteria of Swine Origin

“…Antimicrobial resistance is among the major health challenges of the 21st century, affecting human and animal health in an interdependent way [ 29 ]. Usage of antibiotics in food-producing animals, such as pigs, is related to higher prevalence of resistant bacteria (e.g., E. coli and Salmonella ) in both animals and humans [ 30 ]. In order to reduce antibiotic consumption in farm animals, research for alternative strategies that promote gastrointestinal health is of utmost importance [ 3 ].…”

Pathogenicity of Shiga Toxin Type 2e Escherichia coli in Pig Colibacillosis

“…Escherichia coli is a facultative anaerobe (1) and, although an opportunistic pathogen commonly found in the intestinal tracts of vertebrates (2), has the potential to cause seriously pathogenic colibacillosis in humans and animals, when it harbors specific virulence genes (3). Indeed, even if most E. coli are harmless, some of them are able to cause gastroenteric/enteric or systemic diseases in vertebrates (4,5).…”

Piglet Gut and in-Barn Manure from Farms on a Raised without Antibiotics Program Display Reduced Antimicrobial Resistance but an Increased Prevalence of Pathogens

“…Our drug-use data showed a 9-fold overall reduction in the amount of antibiotics used for treating piglets in RWA barns compared to non-RWA barns, where these drugs were used mainly for the treatment of limping, scours, and several other classes of injury. Although β-lactam and tetracycline resistance have been shown to be globally prevalent in pig microbiomes [15][16][17], these drug classes remain in use and clinically valuable, even in herds where ARGs are abundant across the microbiome [15,18]. Antifolates, however, which are antibacterial, immunomodulating, and chemotherapeutic agents, are widely used in Canadian swine production, but the mechanism of resistance is less well-documented and likely related to inducing efflux multidrug-resistance [19,20].…”