Biology subjects

Rees, G. M.

Publications and source records attributed to Rees, G. M..

3 recordsLinked to original sources

bioRxiv2020

Measuring antimicrobial use on dairy farms: a longitudinal method comparison study

Antimicrobial use on UK dairy farms is measured for surveillance purposes and utilizes veterinary sales data as a proxy for use. Two other methods of recording use have been used commonly on-farm: medicine waste bins and farm medicine records. However, none of these methods have been validated to measure antimicrobial use. The objectives of this research are to assess agreement between the 3 most common methods for measuring on-farm antimicrobial use with a pre-determined "gold standard" measure. Antimicrobial use was measured prospectively on 26 UK dairy farms using medicine waste bins into which participants placed all discarded medicine packaging for a 12-month period. At the end of 12 months, farm medicine records and veterinary sales data were obtained retrospectively for participating farms. The systematic difference between the mean on-farm antimicrobial use measured by each of the 3 methods with a gold standard measure was investigated using one-way repeated measures ANOVAs. Reliability and clinical relevance of the agreement between each pair of methods was quantified using the concordance correlation coefficient and the Bland-Altman method, respectively. Veterinary sales data shows excellent reliability for all forms of antimicrobial when compared with the gold standard. Medicine waste bins show moderate to excellent reliability for injectables, poor to good reliability for intramammaries and no agreement for other forms of antimicrobial. Farm medicine records do not show agreement for any form of antimicrobial when compared with the gold standard. The use of veterinary sales data as a proxy for on-farm antimicrobial use in the UK represents excellent statistical reliability and offers a clinically acceptable agreement with a gold standard method when used to measure both injectable antimicrobials and intramammary antimicrobials. These results have policy implications both nationally and internationally and are essential in quantifying the actual impact of agricultural antimicrobial use on both animal and human health.

pharmacology and toxicology↗

bioRxiv2019

Evidence for reduced CTX-M carriage in cattle-associated Escherichia coli at low temperatures and on publicly accessible farmland: implications for surveillance and potential for farm-to-human transmission

Little is known about the drivers of critically important antibacterial resistance in species with zoonotic potential present on farms (e.g. CTX-M {square}-lactamase-positive Escherichia coli). Here, we collected samples, monthly over a two-year period, on 53 dairy farms in the South West of England, and data for 610 variables concerning antimicrobial usage, management practices and meteorological factors. We detected E. coli resistant to amoxicillin, ciprofloxacin streptomycin and tetracycline, respectively, in 2754/4145 (66%), 263/4145 (6%), 1475/4145 (36%) and 2874/4145 (69%) of all samples from faecally contaminated sites. E. coli positive for blaCTX-M were detected in 224/4145 (5.4%) of samples. Multilevel, multivariable logistic regression showed antibiotic dry cow therapeutic choice (including use of cefquinome or framycetin) to be associated with increased odds of blaCTX-M positivity. Low temperature was associated with reduced odds of blaCTX-M E. coli positivity in samples and to reduced odds of finding E. coli resistant to each of the four test antibacterials. This was additional to the effect of temperature on total E. coli density. Furthermore, samples collected close to calves had increased odds of having E. coli resistance to each antibacterial or positive for blaCTX-M. Samples collected on pastureland had reduced odds of having E. coli resistant to amoxicillin or tetracycline, and being positive for blaCTX-M. ImportanceAntibacterial resistance poses a significant threat to human and animal health and global food security. Surveillance for resistance on farms is important for many reasons, including to track the impacts of interventions aimed at reducing the prevalence of resistance. In this epidemiological survey of dairy farm antibacterial resistance, we show that local temperature, as it changes over the course of a year, is associated with the prevalence of antibacterial resistant E. coli. Also, that prevalence of resistant E. coli is higher in indoor environments and in environments inhabited by young animals. These findings have profound implications for routine surveillance and for surveys carried out for research. They provide important evidence that sampling at a single time-point and/or single location on a farm is unlikely to be adequate to accurately determine the status of the farm with regard to the presence or number of resistant E. coli.

microbiology↗

bioRxiv2018

Storage of prescription veterinary medicines on UK dairy farms: a cross-sectional study

Prescription veterinary medicine (PVM) use in the United Kingdom is an area of increasing focus for the veterinary profession. While many studies measure antimicrobial use on dairy farms, none report the quantity of antimicrobials stored on farms, nor the ways in which they are stored. The majority of PVM treatments occur in the absence of the prescribing veterinarian, yet there is an identifiable knowledge gap surrounding PVM use and farmer decision making. To provide an evidence base for future work on PVM use, data were collected from 27 dairy farms in England and Wales in Autumn 2016. The number of different PVM stored on farms ranged from 9-35, with antimicrobials being the most common therapeutic group stored. Injectable antimicrobials comprised the greatest weight of active ingredient found while intramammary antimicrobials were the most frequent unit of medicine stored. Antimicrobials classed by the European Medicines Agency as critically-important to human health were present on most farms, and the presence of expired medicines and medicines not licensed for use in dairy cattle was also common. The medicine resources available to farmers are likely to influence their treatment decisions, therefore evidence of the PVM stored on farms can help inform understanding of medicine use.

epidemiology↗