Antimicrobial Resistance Patterns of Escherichia coli Isolated from Sheep and Beef Farms in England and Wales: A Comparison of Disk Diffusion Interpretation Methods

Abstract

Little data exist on the levels of antimicrobial resistance from bacteria isolated from British sheep and beef cattle. The aim of this study was to investigate antimicrobial resistance patterns on sheep and beef farms in England and Wales using multiple interpretation methods. Fecal samples (n = 350) from sheep and beef cattle were collected from 35 farms. Disk diffusion antimicrobial susceptibility testing against ten antimicrobials was carried out for 1115 (699 sheep, 416 beef) β-glucuronidase-positive Escherichia coli isolates. Susceptibility was interpreted using clinical breakpoints, which determine clinically resistant bacteria, and epidemiological and livestock-specific cut-off values, which determine microbiological-resistant bacteria (non-wild type). Using livestock-specific cut-off values, a high frequency of wild type for all ten antimicrobials was observed in isolates from sheep (90%) and beef cattle (85%). Cluster analysis was performed to identify patterns in antimicrobial resistance. Interpretation of susceptibility using livestock-specific cut-off values showed a cluster of isolates that were non-wild type to cefotaxime and amoxicillin/clavulanic acid, whereas clinical breakpoints did not. A multilevel logistic regression model determined that tetracycline use on the farm and soil copper concentration were significantly associated with tetracycline non-wild type isolates. The results suggest that using human clinical breakpoints could lead to both the under-reporting and over-reporting of antimicrobial resistance in sheep and beef cattle.

Epidemiological Cut-Off Values and Multidrug Resistance of Escherichia coli Isolated from Domesticated Poultry and Pigs Reared in Mwanza, Tanzania: A Cross-Section Study

“…This study observed that human clinical breakpoints (CLSI) could lead to both over and under-reporting antimicrobial resistance burdens. Similar observations were made by Doidge et al [ 11 ] in the UK, although it was in sheep and beef.…”

“…The NRI software produced a histogram that showed the ECVs and distribution of wild type (sensitive isolates) and non-wild type (resistant isolates) bacteria and the number of SD from the mean [ 21 , 22 ]. In some circumstances where the obtained ECVs were very low, i.e., a zero or negative number, due to the high resistance of E. coli to a particular antibiotic, mean was used as a tentative ECV estimate as reported elsewhere [ 11 , 23 ].…”

“…However, human antimicrobial susceptibility testing disks and guidelines for interpretation of zones of inhibition used among animal surveillances lack veterinary breakpoints. This practice could over and/or under-report the burden of MDR in livestock [ 11 ].…”

Molecular characterization of some pathogenic bacterial strains and hematobiochemical profile in Barki sheep with diarrhea in Siwa Oasis

“…These finding were in consistent with that shown in previous reports in ewes [32] and in buffalo calves Overall, 80% of the sheep in the Siwa oasis in Egypt were infected with E. coli. Nearly similar finding was observed by [35] in sheep (90%) in England, but away from that reported in sheep (69.7%) in Egypt [36], in chickens (64.1%) in China [37], in sheep (34.7%) and goats (30.7%) in Medina, Saudi Arabia [38] and in lambs (36.84%) in Nigeria [39]. This difference could be caused by differences in geography and the environment.…”

The Role of Grass Compost and Zea Mays in Alleviating Toxic Effects of Tetracycline on the Soil Bacteria Community

“…The antibiotics from the class of tetracyclines deployed most often for therapeutic purposes in animal production include chlorotetracycline, oxytetracycline, and tetracycline [ 3 ]. In many countries, tetracyclines are also often added to feedstuffs for livestock and poultry, and are used in aquaculture as growth stimulants [ 10 , 12 , 13 , 14 ]. Antibiotics are poorly metabolized under in vivo conditions [ 1 , 15 ].…”