Sales data as a measure of antibiotics usage: Concepts, examples and discussion of influencing factors

Importation trends in antibiotics for veterinary use in Rwanda: A retrospective study between 2019 and 2021

Estimating antibiotic consumption in animals is fundamental to guiding decision-making and research on controlling the emergence and spread of antibiotic-resistant bacteria in humans, animals, and the environment. This study aimed to establish importation trends of antibiotics for veterinary use in Rwanda between 2019 and 2021. Data was collected from the Rwanda Food and Drugs Authority's database. Quantities of imported antibiotic active ingredients were computed using the information extracted from the issued import licenses. These quantities were subsequently adjusted per animal biomass. In total, 35,291.4 kg of antibiotics were imported into Rwanda between 2019 and 2021, with an annual mean of 11,763.8 ± 1,486.9 kg. The adjustment of imported quantities of antibiotics per animal biomass revealed that 29.1 mg/kg, 24.3 mg/kg, and 30.3 mg/kg were imported in 2019, 2020, and 2021 respectively. A slight but not statistically significant decline in antibiotic importation was noted in 2020 (p-value = 0.547). Most of the imported antibiotics were indicated to be used in food-producing animals (35,253.8 kg or 99.9% of the imported antibiotics). Tetracyclines (17,768.6 kg or 50.3%), followed by sulfonamides (7,865.0 kg or 22.3%) and aminoglycosides (4,071.1 kg or 11.5%), were the most imported antibiotics over the studied period. It was noted that 78.9% of the imported antibiotics were categorized as highly important antimicrobials for human medicine. This study established a generalized overview of the importation of antibiotics for veterinary use in Rwanda. These results can serve as guidance for the control of antibiotic misuse. They can be used to make a correlation between antibiotic importation, antibiotic consumption, and the occurrence of antibiotic resistance in the country.

Standardization and evaluation of indicators for quantifying antimicrobial use on U.S. dairy farms

Antimicrobial resistance (AMR) is a global One Health threat. A portion of AMR development can be attributed to antimicrobial use (AMU) in animals, including dairy cattle. Quantifying AMU on U.S. dairy farms is necessary to inform antimicrobial stewardship strategies and help evaluate the relationship between AMU and AMR. Many AMU indicators have been proposed for quantifying AMU in dairy cattle. However, these indicators are difficult to interpret and compare because they differ in the type of data used, the calculation approach, and the definitions of variables and parameters used in the calculation. Therefore, we selected 16 indicators (count-based, mass-based, and dose-based) applicable for quantifying AMU on U.S. dairy farms. We systematized the indicators by standardizing their variables and parameters to improve their interchangeability, interpretation, and comparability. We scored indicators against six data-driven criteria (assessing their accuracy, data and effort needs, and level of privacy concern) and five stewardship-driven criteria (assessing their ability to capture trends and inform antimicrobial stewardship). The derived standardized indicators will aid farmers and veterinarians in selecting suitable indicators based on data availability and stewardship needs on a farm. The comparison of indicators revealed a trade-off requiring farmers to balance the granularity of data necessary for an accurate indicator and effort to collect the data, and a trade-off relevant to farmers interested in data sharing to inform stewardship because more accurate indicators are typically based on more sensitive information. Indicators with better accuracy tended to score better in stewardship criteria. Overall, two dose-based indicators, estimating the number of treatments and administered doses, scored best in accuracy and stewardship. Conversely, two count-based indicators, estimating the length of AMU, and a mass-based indicator, estimating the mass of administered antimicrobials, performed best in the effort and privacy criteria. These findings are expected to benefit One Health by aiding the uptake of farm-level AMU indicators by U.S. dairy farms.

Antimicrobials in Animal Agriculture in the United States: A Multidisciplinary Overview of Regulation and Utilization to Foster Collaboration: On Behalf Of the Society of Infectious Diseases Pharmacists

Given the complexity of antimicrobial resistance and the dire implications of misusing antimicrobials, it is imperative to identify accurate and meaningful ways to understand and communicate the realities, challenges, and opportunities associated with antimicrobial utilization and measurement in all sectors, including in animal agriculture. The objectives of this article are to (i) describe how antimicrobials are regulated and used in US animal agriculture and (ii) highlight realities, challenges, and opportunities to foster multidisciplinary understanding of the common goal of responsible antimicrobial use. Recognition of the realities of medicine, practice, and policy in the agricultural setting is critical to identify realistic opportunities for improvement and collaboration.

Role of environmental stresses in elevating resistance mutations in bacteria: Phenomena and mechanisms

Mutations are an important origin of antibiotic resistance in bacteria. While there is increasing evidence showing promoted resistance mutations by environmental stresses, no retrospective research has yet been conducted on this phenomenon and its mechanisms. Herein, we summarized the phenomena of stress-elevated resistance mutations in bacteria, generalized the regulatory mechanisms and discussed the environmental and human health implications. It is shown that both chemical pollutants, such as antibiotics and other pharmaceuticals, biocides, metals, nanoparticles and disinfection byproducts, and non-chemical stressors, such as ultraviolet radiation, electrical stimulation and starvation, are capable of elevating resistance mutations in bacteria. Notably, resistance mutations are more likely to occur under sublethal or subinhibitory levels of these stresses, suggesting a considerable environmental concern. Further, mechanisms for stress-induced mutations are summarized in several points, namely oxidative stress, SOS response, DNA replication and repair systems, RpoS regulon and biofilm formation, all of which are readily provoked by common environmental stresses. Given bacteria in the environment are confronted with a variety of unfavorable conditions, we propose that the stress-elevated resistance mutations are a universal phenomenon in the environment and represent a nonnegligible risk factor for ecosystems and human health. The present review identifies a need for taking into account the pollutants' ability to elevate resistance mutations when assessing their environmental and human health risks and highlights the necessity of including resistance mutations as a target to prevent antibiotic resistance evolution.

Comparison of different biomass methodologies to adjust sales data on veterinary antimicrobials in the USA

Objectives

The United States (US) FDA, European Surveillance of Veterinary Antimicrobial Consumption (ESVAC), Public Health Agency of Canada (PHAC) and World Organisation for Animal Health (OIE) established methodologies that characterize antimicrobial sales for use in food animals by adjusting the sales by animal biomass. Our aim was to review and compare these methodologies on US-specific data.

Methods

Annual antimicrobial sales for cattle, swine, chickens and turkeys in the USA between 2016 and 2018 were adjusted by the FDA, ESVAC, PHAC and OIE methodologies. To better understand the advantages and disadvantages of the four methodologies, their biomass denominators were compared regarding the level of detail accounted for in the estimated US livestock biomass, their ability to observe temporal trends in animal biomass within a country and practicality in biomass estimation for comparing antimicrobial sales across countries.

Results

The four methodologies resulted in substantially different estimates of biomass-adjusted antimicrobial sales for use in US food animals. The 2018 estimates were the highest with the ESVAC methodology (314.7 mg of active antimicrobial ingredient/kg of animal biomass), followed by PHAC (191.5 mg/kg), FDA (127.6 mg/kg) and OIE (111.5 mg/kg). The animal weight parameters used in each methodology had the most impact on the biomass-adjusted sales estimates.

Conclusions

In regard to the estimation of the animal biomass, no methodology was found to be perfect; however, the FDA methodology had the best resolution in characterizing the US livestock biomass while the OIE methodology was best for biomass estimation for global monitoring of antimicrobial sales for use in food animals.

Trends in estimated intramammary antimicrobial usage in the Irish dairy industry from 2003 to 2019

The objective of this study is to update earlier work on intramammary (IM) antimicrobial (AM) usage in Ireland. There is a need to measure AM usage in food-producing animals given increasing societal concerns about AM resistance as well as recent regulatory changes that dictate changes in how AM are used in food-producing animals and how AM sales and usage are recorded. National sales data were collected and used in this analysis. Sales of the number of IM AM tubes and amount of active ingredient sold were analyzed each year by product type [in-lactation (LC) therapy and dry cow (DC) therapy] and classification system (World Health Organization and more recent European Medicine Agency). Descriptive trends in estimated IM AM use are presented, including defined course dose (DCDvet; a technical unit for on-farm usage). There has been a decrease in estimated on-farm usage of IM AM during lactation, from 0.48 DCDvet/cow per year in 2015 to 0.43 DCDvet/cow per year in 2019. Almost all LC therapies sold include critically important AM (CIA), with 98% of the total DCDvet administered for LC therapy in 2019 containing at least 1 CIA. There has been a slow increase in tubes containing at least 1 highest priority CIA in LC therapies, from 0.01 DCDvet/cow per year in 2003, accounting for 2% of the total DCDvet administered for LC therapy, to 0.03 DCDvet/cow per year in 2019, accounting for 7% of the total DCDvet administered for LC use. The estimated usage of IM AM DC therapy has decreased from 1.09 DCDvet/cow per year in 2015 to 0.95 DCDvet/cow per year in 2019. In the last 5 yr, more than 40% of the total DC DCDvet administered contained at least 1 CIA, and there has been an increase in recent years in the percentage of the total DC DCDvet administered that contains at least 1 highest priority CIA, driven mainly by use of fourth-generation cephalosporin. This work provides further insights into IM AM usage in Ireland and highlights some important areas for attention, including availability of farm-level usage data, prescribing practices, and usage of important AM.

Joint effects of antibiotics and quorum sensing inhibitors on resistance development in bacteria

Quorum sensing inhibitors (QSIs) are promising alternatives to antibiotics. While QSIs have great application potential in a variety of fields, their joint effects with antibiotics on bacteria, especially on antibiotic resistance mutations, remain largely unexplored. Herein, we report the joint effects of four commonly used antibiotics and two QSIs on bacterial growth and resistance mutations in E. coli. It was found that QSIs presented antagonistic or additive effects with antibiotics on bacterial growth, and more importantly, QSIs exhibited an attenuating effect on antibiotic-induced resistance mutations. Further analysis demonstrated that antibiotics might enhance resistance mutations by promoting the expressions of rpoS, lexA and recA, while QSIs attenuated the mutations by promoting the expressions of mutS and uvrD. The present research provides a comprehensive understanding of the joint effects of antibiotics and QSIs on bacteria, which may benefit the risk assessment of their combined exposure.

Estimates of on-farm antimicrobial usage in turkey production in the United States, 2013-2017

With increasing concern about the emergence and spread of resistant bacteria, there is an increasing motivation to optimize antimicrobial use administrations in animal agriculture. A key component of antimicrobial stewardship is the ability to collect antimicrobial use data and ultimately use this information to assess that administrations are necessary and effective. The objective of this study was to develop a system for collecting on-farm antimicrobial use data from the US turkey industry and to have it be representative of the largest commercial turkey producers in the United States that comprise the vast majority of national turkey production. Participation was voluntary. Data were collected for the period 2013 through 2017 and are reported on a calendar year basis. Using statistics from USDA:NASS as a denominator, the data supplied by participating companies represented approximately 67.3% of turkey production in the United States in 2013 and increased to approximately 69.8% in 2017. The data that were submitted for 2017 are based on approximately 187,016,604 poults placed, 164,081,335 turkeys slaughtered, and 5,178,431,422 pounds liveweight produced. The estimated percentage of turkey poults placed that received hatchery antimicrobials decreased from 96% in 2013 to 41% in 2017. Medically important in-feed antimicrobial use decreased substantially. For example, in-feed tetracycline use decreased approximately 67% between 2013 and 2017. Medically important water-soluble antimicrobial use decreased substantially for most antimicrobials. Between 2013 and 2017, water-soluble penicillin use decreased approximately 42%, water-soluble tetracycline use decreased approximately 28%, and water-soluble lincomycin use decreased approximately 46%. Reducing the total amounts of antimicrobials used might be a crude indicator for mitigating the selection of antimicrobial resistance. Reducing the need for such use and verifying that treatment regimens deliver beneficial outcomes to animal health are more meaningful objectives.

Antimicrobial use in wean to market pigs in the United States assessed via voluntary sharing of proprietary data

Data on antimicrobial use were collected for the 2016 and 2017 calendar years from swine producers in the United States. Nine large systems, collectively producing over 20 million market pigs annually, voluntarily provided data to advance understanding of antimicrobial use in the industry and to support antimicrobial stewardship initiatives. The scope of the study was limited to growing pigs, and the granularity of data varied across the systems. Data were summarized both qualitatively and quantitatively by antimicrobial class, active ingredient and route of administration (injection, water and feed). Data on the purpose of administration, doses and durations of administration were not available, but some information was provided by the responsible veterinarians. Aggregate data were similar both qualitatively and quantitatively in 2016 and 2017, although marked changes between years were evident within systems for some antimicrobials. Antimicrobial use (by weight) was dominated by the tetracycline class (approximately 60% of total use). Antimicrobials in classes categorized as critically important constituted 4.5% and 5.3% of total use in 2016 and 2017, respectively. In both years, fluoroquinolone (0.23%, 0.46%) and 3rd generation cephalosporin (0.15%, 0.11%) use collectively accounted for <1% of total use. Administration was predominantly oral in feed and water, and injection comprised approximately 2% of use overall, but around 12% for critically important antimicrobials. There was considerable variability among systems in patterns of antimicrobial use. This pilot project demonstrates the feasibility of acquiring antimicrobial use data via voluntary sharing. It is currently being expanded among larger swine production systems, and further efforts to enable confidential data sharing and benchmarking for smaller producers are being pursued by the swine industry. Recognized biases in the data caution against over-interpretation of these data as an index of national use.

Estimates of on-farm antimicrobial usage in broiler chicken production in the United States, 2013-2017

Antimicrobial use is a key selective force behind the emergence of resistant bacteria. Therefore, optimizing strategies for more efficacious and targeted antimicrobial use is an essential component of efforts to combat antimicrobial resistance. To bolster stewardship programmes in animal agriculture, processes are needed for the systematic collection of on-farm antimicrobial use data. The objective of this study was to develop a system for collecting on-farm antimicrobial use data from the US broiler industry and to have it be representative of the largest commercial broiler producers in the United States that comprise the vast majority of national broiler production. Participation was voluntary. Data were collected for the period 2013 through 2017 and are reported on a calendar year basis. Using statistics from USDA:NASS as a denominator, the data supplied by participating companies accounted for approximately 81.7% of broiler production in the United States in 2013 and increased to approximately 87.2% in 2017. The data that were submitted for 2017 are based on approximately 7,897,339,357 chicks placed, 7,541,449,430 chickens slaughtered and 48,225,124,865 pounds liveweight produced. The use of antimicrobials in the hatchery decreased substantially between 2013 and 2017; the approximate percentage of broiler chicks placed that received hatchery antimicrobials decreased from 93% in 2013 to 17% in 2017. Medically important in-feed antimicrobial use decreased substantially. For example, in-feed tetracycline use decreased approximately 95% between 2013 and 2017. Medically important water-soluble antimicrobial use decreased substantially for most antimicrobials. Between 2013 and 2017, water-soluble penicillin use decreased approximately 21%, water-soluble tetracycline use decreased approximately 47%, and water-soluble lincomycin use decreased approximately 28%. While a reduction in antimicrobial amounts used may be an important indicator of improved stewardship, reducing the need for antimicrobials through improved disease prevention should be considered a more important objective and a better indicator of overall flock health and optimal antimicrobial use.

Sales data as a measure of antibiotics usage: Concepts, examples and discussion of influencing factors

Monitoring and surveillance of antimicrobial usage in animals is a public health concern and different methods are currently discussed widely in public, science and politics. The objective of the paper is to present the available methods of monitoring and to discuss possible differences in the assessment of the antibiotics treatment. Sales data are expressed as the average amount of substance per animal or kg live weight (e.g. population‐corrected unit, PCU). The number of Defined Daily Doses (nDDDvet) is calculated by extrapolating sales data with average animal weights and defined drug doses to a number of treatments theoretically applied to animals. In contrast, the number of Used Daily Doses (nUDDvet) displays the actual number of treatments which have been applied. As sales data are relatively easily obtained, they are frequently used. However, their results are influenced by the composition of the population and by the dose of the substances. As both may vary strongly between countries, direct comparison of sales data between countries may be misleading. The concept of analysing sales data is shown by exemplarily using the methods in the ESVAC report 2015. The presentation of usage data in terms of nDDDvet or of nUDDvet increases the comparability of the data from different countries or time periods. Furthermore, fluoroquinolones and third‐/fourth‐generation cephalosporins which, among other substances, bare a potential risk for human health, are used at low doses. Hence, their use contributes to a sales reduction while contrasting the guidelines of prudent use. nDDDvet or nUDDvet have the ability to better reflect the treatment frequency and thus to better link antibiotics use to public health concerns. Quantification of antibiotics should assist to focus on prudent use of antimicrobials to reduce the burden of resistant bacteria and, thus, enhance public health, animal health and animal welfare.