Reduction In Antimicrobial Use Research Articles

Economic assessment of an intervention strategy to reduce antimicrobial usage in small-scale chicken farms in Vietnam

Antimicrobials are a core aspect of most livestock production systems, especially in low-and middle-income countries. They underpin the efficient use of scarce feed resources and stabilize returns on capital and labor inputs. Antimicrobial use (AMU) contributes to the production of healthy animals, yet AMU in livestock is linked to antimicrobial resistance (AMR) in animals, humans and the environment.The Vietnamese Platform for Antimicrobial Reduction in Chicken Production was implemented during 2016–2019 and was one of Southeast Asia's first interventions focused on AMU reductions in livestock production. The project targeted small-scale commercial poultry farms in the Mekong Delta region of Vietnam using a “randomized before-and-after controlled” study design. It provided farmers with a locally adapted support service (farmer training plan, advisory visits, biosecurity, and antimicrobial replacement products) to help them reduce their reliance on antimicrobials. A partial budget analysis was performed comparing the control group (status-quo) and intervention group (alternative). The median net farm-level benefit of the intervention strategies with the project's support was VND 6.78 million (interquartile range (IR) VND -71.9–89 million) per farm. Without project support the benefit was reduced to VND 5.1 million (IR VND -69.1–87.2 million) to VND 5.3 million (IR -VND 68.9–87.5 million) depending on the antimicrobial alternative product used. At the project level with a focus on AMU and its reduction, subsequently influence on the resistance reduction, our results showed that achieving resistance reduction benefits with the current knowledge and technologies required investment of at least VND 9.1 million (US$ 395.10) per farm during the project's lifetime. The results highlight the positive net profit for the majority of enrolled farms and a reasonable investments from the project. The recommendation focuses on the implementation of policies on financial support, legislation, and information as potential solutions to facilitate the application of intervention strategies to reduce AMU in poultry production.

An economic assessment of alternative antimicrobial use scenarios on pig farms.

This paper explores the theoretical economic outcome of management changes that result in different levels of antimicrobial use (AMU) in two types of UK pig farm. A static farm economic pig production model (FEPM) was used on a representative 'Top-third' most profitable farm and a representative 'Mid-range' profitable farm. Three AMU theoretical management scenarios were investigated; (a) management changes leading to a reduction of AMU by 35% (AMU35); (b) more extensive management changes leading to a reduction of AMU by 95% (AMU95); and (c) implementing depopulation of the herd (AMU Depop). A sensitivity analysis was conducted to determine the effect of increases or decreases in pig revenue and feed price on farm gross margin under these scenarios. Over a single year, the AMU35 scenario was estimated to have a small positive impact (+3%) on both farm types. The other two AMU reduction scenarios had higher AMU reduction on farms but required higher variable cost and hence they resulted in lower farm profitability. There was a substantial reduction (up to -50%) in farm gross margin under these two AMU reduction scenarios in the modeled short-term time-period. The impact of the alternative AMU scenarios was slightly higher on a farm representing the 'Top-third' farm type, reducing farm gross margin further by 7% compared to the 'Mid-range' farm. Nevertheless, both farm types stay profitable under all three AMU scenarios. The results showed that in the modeled short-term implementing management changes that result in a reduction of on-farm AMU by 35% had a good economic outcome. In practice, the other two scenarios would be considered as longer-term strategies. Although both require higher initial costs to implement, the improved biosecurity and hygiene will benefit from lower disease occurrence for a longer term. Farm gross margins were, however, found to be highly sensitive to changes on market prices especially increasing feed prices. An increase of more than 15% in feed price moved a profitable farm into a loss-making farm. It will be economically challenging for uptakes of these, or similar, AMU reduction scenarios on farms if the market prices become un-favorable to pig farmers.

Identifying and addressing barriers and opportunities for bovine respiratory disease complex vaccination: a consensus paper on practical recommendations for best practise vaccination.

Many questions are raised, and challenges faced in the new era of (intranasal) bovine respiratory disease complex vaccination. An increase in vaccination rate is expected, due to its positive impact on cattle health, reduction of antimicrobial use and economic factors. However, engagement of farmers and veterinarians with regard to vaccination is often affected by limitations, resulting in the development of barriers to vaccination, but also opportunities to overcome these. The objective of the report is to provide practical recommendations and a consensus on best practises for BRDC vaccination, addressing barriers faced by veterinarians and farmers. The report combines an evidence review with expert opinions and includes discussions on different vaccination approaches, such as intranasal and systemic protocols. As result of the discussions, several barriers to BRDC vaccination were identified, including a lack of knowledge or visibility of the disease's impact, the preference for blanket antibiotic use over vaccination, resistance to change, the need for visible success, uncertainty about the best time to vaccinate, and concerns about adverse reactions and vaccine efficacy in the presence of maternal antibodies. While these barriers seem substantial, they provide opportunities for the veterinary sector. Indeed, veterinarians are encouraged to use the argumentation presented, along with local case studies and diagnostic testing to highlight the impact of disease, while conducting calf health audits, ensuring expectations are managed to achieve visible success. Overall, this consensus paper aims to provide practical recommendations and support for veterinarians and farmers to overcome barriers and increase BRDC vaccination rates in cattle.

- Invited Review - Current status and future trends for pork production in the United States of America and Canada.

Pork production is a significant agricultural enterprise in the United States and Canada. The United States is the third-largest global producer of pork and Canada ranks seventh in pork production. The North American Free Trade Agreement and its successor, the U.S.-Mexico-Canada Agreement, have facilitated trade and integration between the two countries. The majority of production systems are modern and intensive, characterized by large vertically integrated farms using advanced technologies. Both nations benefit from their status as major producers of feed grains, with the United States leading in corn and soybeans, while Canada excels in canola and barley production. The regulatory frameworks for food safety, animal welfare, and environmental stewardship differ slightly, with the FDA and USDA overseeing these aspects in the United States, and Health Canada and the Canada Food Inspection Agency in Canada. The United States and Canada also have well-established distribution networks for pork products, relying on both domestic and international markets. Export markets play a crucial role, with the United States being a major importer of Canadian pigs, and both countries exploring opportunities in Asia. Despite a rise in global demand, domestic pork consumption trends differ, with per capita consumption remaining stable in the USA and declining in Canada. Changing consumer preferences, including a demand for ethically raised and locally sourced pork, may influence production practices. Future trends in pig production include a focus on consumer concerns, sustainability, disease prevention, reduction of antimicrobial use, and advancements in technology. The industry is adapting to challenges such as disease outbreaks and changing regulations, with a strong emphasis on animal welfare. Labor and workforce considerations, along with advancements in technology and automation, are expected to shape the efficiency of pork production in the future.

Approach Choices for Antimicrobial Use Reduction in European Food Animal Production

SummaryReducing antimicrobial use (AMU) stands as a pivotal global strategy in combating antimicrobial resistance (AMR) within the realm of food animal production. We conducted an extensive review of the distinct approaches employed in managing AMU reduction within the United Kingdom, Denmark and the Netherlands. Our analysis delved into the reform processes, emphasising the roles played by government, the general public and key stakeholders throughout the supply chain. Furthermore, we examined the impacts of these approaches on AMU, AMR and the economic landscape of food animal production. In all three countries, these reforms have been anchored in the reduction and judicious utilizsation of Critically Important Antimicrobials (CIAs) for veterinary use. These efforts have yielded significant outcomes, particularly in the reduction of CIA use. In utilising a voluntary approach to AMU reduction, the active involvement of government bodies, consumers and supply chain leaders, notably supermarkets, has proven to be pivotal. In terms of execution, these countries have adopted varied management strategies, including voluntary, regulatory and hybrid approaches, championed by farmers, government agencies and veterinarians, respectively. These approaches have yielded diverse impacts, both in terms of their potential for reduction and their influence on farm performance.

Application of behavior data to predictive exploratory models of metritis self-cure and treatment failure in dairy cows

The objective was to evaluate the performance of exploratory models containing routinely available on-farm data, behavior data, and the combination of both to predict metritis self-cure (SC) and treatment failure (TF). Holstein cows (n = 1,061) were fitted with a collar-mounted automated- health monitoring device (AHMD) from -21 ± 3 to 60 ± 3 d relative to calving to monitor rumination and activity. Cows were examined for diagnosis of metritis at 4 ± 1, 7 ± 1, and 9 ± 1 DIM. Cows diagnosed with metritis (n = 132), characterized by watery, fetid, reddish/brownish vaginal discharge (VD) were randomly allocated to one of 2 treatments: Control (CON; n = 62) - no treatment at the time of metritis diagnosis (d 0); Ceftiofur (CEF; n = 70) - subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid on d 0 and 3 relative to diagnosis. Cure was determined 12 d after diagnosis and was considered when VD became mucoid and not fetid. Cows in CON were used to determine SC and cows in CEF were used to determine TF. Univariable analyses were performed using farm-collected data (parity, calving season, calving-related disorders, body condition score, rectal temperature, and days in milk at metritis diagnosis) and behavior data (i.e., daily averages of rumination, activity generated by AHMD, and derived variables) to assess their association with metritis SC or TF. Variables with a P ≤ 0.20 were included in the multivariable logistic regression exploratory models. To predict SC, the area under the curve (AUC) for the exploratory model containing only data routinely available on-farm was 0.75. The final exploratory model to predict SC combining routinely available on-farm data and behavior data increased the AUC to 0.87, sensitivity (Se) 87% and specificity (Sp) 71%. To predict TF, the AUC for the exploratory model containing only data routinely available on-farm was 0.90. The final exploratory model combining routinely available on-farm data and behavior data increased the AUC to 0.93, Se of 93% and Sp of 82%. Cross-validation analysis revealed that generalizability of the exploratory models was poor, which indicates that the findings are applicable to the conditions of the present exploratory study. In summary, the addition of behavior data contributed to increasing the prediction of SC and TF. Developing and validating accurate prediction models for SC could lead to a reduction in antimicrobial use, whereas accurate prediction of cows that would have TF may allow for better management decisions.

Recording Antimicrobial Use on Irish Dairy Farms: Barriers & Facilitators to Using Technology and Sharing Data

Antimicrobial use (AMU) data are essential to monitor the impact of AMU reduction strategies in animal health. The use of technology and herd recording software to record AMU will be vital to scale the collation of these data in the future. The aim of this study was to determine the barriers and facilitators to Irish dairy farmers recording their AMU using a herd recording software and sharing AMU data. Thirty-three Irish dairy farmers involved in a study on AMU monitoring were asked to record their AMU using a herd recording software over a 12-mo period. At the end of the 12-mo period, 10 of these farmers were selected to take part in semi-structured interviews exploring their opinions on recording AMU, the use of herd recording software, and sharing AMU data. Interviews were transcribed and qualitatively analyzed using inductive thematic analysis. Several barriers and facilitators to farmers recording their AMU using a herd recording software and sharing AMU data were identified. Barriers included the age and generation of the farmer, farm infrastructure, a lack of training and education, a lack of knowledge around the benefits of digital data, a lack of incentive to digitalise records, and a fear of repercussions. Facilitators identified by the farmers included the benefits of having instantly available data for making herd management decisions, reduced paperwork, increased organization for inspections, and a potential positive impact on the image of the dairy industry. To increase the uptake of new technology to record AMU at farm-level, farmers will need support in terms of education and training around the software available to them and reassurance around the perceived risks of repercussions with sharing data in a digital format.

Associations of Swiss national reporting system's antimicrobial use data and management practices in dairy cows on tie stall farms

Antimicrobial use (AMU) in Switzerland is above target and requires reduction especially in dairy cattle. Measuring AMU is pivotal to identify starting points for AMU reduction and so are studies investigating its potential drivers in dairy farms worldwide. However, although AMU in dairy farms is high, studies estimating AMU specifically in tie stall farms are scarce. Tie stalls are a common housing system and their prevalence among dairy farms accounts to approximatively 73%, 41% and 40% in Canada, the US and Switzerland, respectively. The objectives of this cross-sectional, retrospective observational study were to estimate AMU using the newly established Swiss national reporting system for AMU in livestock and to identify associated factors on Swiss tie stall dairy farms. We calculated the treatment incidence (TI) by using the European Medicines Agency's methodology and their Defined Daily and Defined Course Dose (DDD/DCD) standards. Data on factors potentially associated with AMU were obtained through personal interviews with farm managers on 221 farms. Retrospectively, during a 1-year period, data on a total of 7,619 treatments were extracted from the national database. Associations between management factors and TI were analyzed using a generalized linear model with gamma distribution. The mean overall TI was 5.46 DDD/cow-year (±standard deviation: 4.10 DDD/cow-year). Intramammary treatment during lactation accounted for highest TI (3.24; ± 3.16 DDD/cow-year), whereas dry-cow therapy accounted for lowest TI (0.44; ± 0.49 DCD/cow-year). Five of the investigated management factors were significantly associated with TI. Organic production (estimate -2.16; 95% confidence interval [95 CI] -3.62, -0.70) and herd size (estimate -0.81; 95 CI -1.23, -0.39) were negatively associated with TI. Specific cow breeds (Brown Swiss and Holstein Friesian: estimate 1.56; 95 CI 0.45, 2.68; estimate 1.42; 95 CI 0.03, 2.82, respectively; reference: other breeds) and the use of hygienic powders on the lying area (estimate 1.10; 95 CI 0.04, 2.17) were positively associated with TI. In conclusion, the Swiss national reporting system is a valuable tool for AMU estimation. Several herd characteristics and management factors were associated with AMU in tie stall farms. Further studies focusing on factors associated with AMU and which are amenable to intervention will help improve stewardship programs and subsequently reduce AMU in dairy cows.

Regulating antimicrobial resistance: market intermediaries, poultry and the audit lock-in

Antimicrobial resistance (AMR) has become one of the defining challenges of the twenty-first century. Food production and farming are a key if troubling component of that challenge. Livestock production accounts for well over half of annual global consumption of antimicrobials, though the contribution of the sector to drug resistance is less clear. As a result, there is an injunction to act in advance of incontrovertible evidence for change. In this paper we engage with the role of market actors in the precautionary regulation of farming practices and AMR threats. The paper takes the UK poultry sector as exemplary of an audit-led process that has, in recent years, achieved impressive reductions in antimicrobial use. Using qualitative interview data with farmers and veterinarians we chart the changing practices that have accompanied this reduction in treatments. We use this analysis to raise some cautions around audit-led systems of regulation. Audits can lock farms and animals into particular versions of farming and animal health; they can elevate harmful compensatory practices (including disinfectant uses); and they can reproduce an actuarial approach to an issue that does not fit the conventions of risk management. The paper presents the considerable successes that have been achieved over a short period of time in a livestock sector, while generating notes of caution concerning the audit-led management of livestock-related AMR threats.

2197. Impact of an INtake FOrm for Restricted Medications to (INFORM) better antibiotic use within a long-term acute care hospital system

Abstract Background Long-term Acute Care Hospitals (LTACHs) are uniquely positioned to treat patients with a high severity of illness for a long period of time. Despite this, there are substantial barriers to providing antimicrobial stewardship in this setting including limited resources and lack of patient data from transferring facilities. Methods This multi-center retrospective, quasi-experimental study evaluated the use of broad-spectrum antibiotics (BSAbx) over 3 timeframes in 43 LTACHs and rehabs within the Post Acute Medical System. Despite implementation of a restriction policy in June 2018, use remained high for ceftolozane/tazobactam (C/T), ceftazidime/avibactam (CZA), and meropenem/vaborbactam (MEV). In July 2020, the system antimicrobial stewardship committee created an INtake FOrm for Restricted Medications (INFORM) that required submission of pertinent clinical information for each patient receiving one of the target antibiotics as well as systematic review by an ID pharmacist. An electronic version of the INFORM was implemented in April 2022. Study timeframes included baseline (BL: July 2019-June 2020), phase 1 (P1: July 2020-March 2022), and phase 2 (P2: April 2022-March 2023). The primary objective was to determine if there was a difference in the combined use of C/T, CZA, and MEV measured as cost/acute patient day (APD) across the three timeframes. Secondary analyses included post-hoc analyses between these groups, and an evaluation of C/T, CZA, MEV with the addition of imipenem/cilastatin/relebactam (I/C/R). Results There was a significant reduction in antimicrobial use across intervention periods (mean cost/APD BL=2.5, P1=1.3, P2=0.8, p=0.045 using ANOVA, Figure 1). Sub-hoc analyses showed a significant difference for BL:P1 (p=0.02) and BL:P2 (p< 0.01), but not for P1:P2 (p=0.6). Even when adding I/C/R to control for any shifts in utilization to this agent after it was approved by the FDA, there was a statistically significant reduction across the intervention periods (p< 0.01 using ANOVA, Figure 2). Figure 2: Cost/Acute Patient Day for C/T, CZA, MEV vs. I/C/R over time C/T = ceftolozane/tazobactam, CZA = ceftazidime/avibactam, MEV = meropenem/vaborbactam, I/C/R = imipenem/cilastatin/relebactam Conclusion Completion of both the paper and electronic INFORM reduced C/T, CZA, and MEV use from baseline, showing that the systematic collection and review of patient data by an ID pharmacist reduced use of these BSAbx in a system of LTACHs and rehabs. Disclosures All Authors: No reported disclosures

Antimicrobial Use in On-Farm Hatching Systems vs. Traditional Hatching Systems: A Case Study.

On-farm hatching is a relatively new method in the broiler industry, in which fertilized broiler eggs are transported to the farms at the stage of 17-19 days of incubation. Once hatched, the broiler chicks have direct access to feed and water. Previous studies have shown on-farm hatching to increase animal welfare and intestinal development. However, no studies have yet aimed to quantify and compare the antimicrobial use in on-farm hatched flocks with that of traditionally hatched flocks. In this study, information on antimicrobial use (AMU) was collected from 211 Belgian conventional broiler farms, including data from 2244 traditionally hatched flocks and 227 on-farm (NestBorn) hatched flocks. On-farm hatched flocks had significantly (p < 0.001) more antimicrobial-free flocks (n = 109, 48.01%) compared to traditional flocks (n = 271, 12.08%) and a 44% lower (p < 0.01) treatment incidence (TI) at flock level (TI 8.40 vs. TI 15.13). Overall, the farms using traditional hatching had 5.6 times (95% CI 3.6-8.7) higher odds to use antimicrobials than the farms using on-farm hatching. Treated on-farm hatched flocks received three times less lincomycin-spectinomycin (linco-spectin) and less (routine) treatments at the start of the production round. However, both traditional and on-farm flocks experienced outbreaks later in the production round. These results show that on-farm hatching can contribute to the reduction in antimicrobial use in conventional broiler production.

The Effects of Milk Replacer Supplemented with Ascophyllum nodosum as a Novel Ingredient to Prevent Neonatal Diarrhea in Dairy Calves and Improve Their Health Status.

Nutrition and health during pre-weaning affect the calves' future fertility, calving age, production, and carrier length. Calves are highly susceptible to neonatal calf diarrhea (NCD), which can be fatal. NCD is due to hypovolemia and acidosis, which may involve anorexia and ataxia. The One Health principle calls for a drastic reduction in antimicrobial use. One approach is to improve animal health and reduce the use of antibiotics and functional ingredients that have beneficial effects due to bioactive compounds. Several functional ingredients and additives can be considered, and, in particular for this study, Ascophyllum nodosum was considered. The present study aimed to evaluate the role of A. nodosum as a functional ingredient implemented into the milk replacer in neonatal calves. Twelve pre-weaned Holstein Frisian calves, housed in twelve individual pens in the same environmental conditions, were divided into two groups of six animals: a control group (CTRL, n = 6) fed with a milk replacer, and a treatment group receiving milk enriched with 10 g of A. nodosum in their diet (TRT, n = 6) for 42 days. The fecal score was evaluated daily (3-0 scale) to monitor the incidence of diarrhea in the two groups. The body weight was evaluated weekly, and every two weeks feces were collected for microbiological evaluation using a selective medium for plate counting of total, lactic acid, and coliform bacteria. To verify the presence of Lactobacillus, Bifidobacterium, and Escherichia coli, real-time qPCR was used. At the beginning and at the end of the trial, blood samples were obtained for serum metabolite analysis. The growth performance did not differ in either of the two groups, but significant differences were observed in the incidence of moderate diarrhea (p-value < 0.0113), where the TRT group showed a lower incidence of cases during the 42-day period. Serum analysis highlighted higher contents of albumin, calcium, phosphorus, and total cholesterol in the TRT group compared to CTRL (p-value < 0.05). In conclusion, implementation of A. nodosum in the diet of calves can lead to better animal welfare and may reduce the use of antibiotics.

Antimicrobial resistance interventions in the animal sector: scoping review

Animals are considered key contributors to the development and spread of antimicrobial resistance (AMR). However, little is known about the existing AMR interventions in the animal sector. This scoping review examines the existing evidence on AMR interventions aimed at livestock, animal health professionals (AHPs), and farmers, while reviewing their impact, limitations, gaps, and lessons for future use. The scoping review was conducted following guidelines from the PRISMA-ScR checklist. The databases, Web of Science, Scopus, PubMed, and international organisations’ websites (WHO, FAO, WOAH) were searched for articles reporting interventions targeting livestock, farmers, and AHPs. Interventions were categorised based on seven pre-defined primary measures including: change in antimicrobial use (AMU) practices; change in the uptake of antimicrobial stewardship (AMS); change in development of AMR; change in knowledge of appropriate AMU practices, AMR, and AMS; change in attitudes and perceptions concerning AMU, AMR, and AMS; and surveillance strategies. In total, ninety three sources were included: 66 studies, 20 reports, and 7 webpages. The reviewed interventions focused mostly on AMU practices (22/90), AMS uptake (8/90), and reduction of bacterial or resistant strains (30/90). Changes in knowledge (14/90) and attitude (1/90) were less frequently assessed and were often implicit. Most interventions were conducted within a select country (83/90) and 7/90 were at a global level. Only 19% (16/83) of interventions were implemented in low- and middle-income countries (LMICs) and most were at herd level with many self-reporting changes. Most of the interventions that focused on surveillance strategies (30/83) were implemented in high-income countries (62/83). Only one study investigated the financial implications of the intervention. The study findings provide an overview of existing AMR interventions and insights into the gaps which can be addressed to guide future interventions and research. A focus on developing, implementing and evaluating interventions in LMICs coupled with the use of objective outcome measures (e.g., measurable outcomes vs. self-reporting) will improve our understanding of the impact of interventions in these settings. Finally, assessing the financial benefits of interventions is necessary to inform feasibility and to encourage uptake of interventions aimed at reducing AMR in the animal health sector.

Comprehensive analysis of biosecurity practices and antimicrobial use in broiler chicken production by integrated operations in Korea

Integrated broiler operations that allow producers to combine various biosecurity and sanitation practices account for approximately 97.6% of chicken meat production in Korea, but it is not well known about the biosecurity level or compliance with regulations for each operation. Therefore, the objective this study was to analyze the current adoption of biosecurity practices and trends in antimicrobial use in 74 farms from 5 major integrated broiler chicken operations (A-E). The highest stock densities of more than 65 birds per 3.3 m2 (0.5 birds/ft2) showed in 66.7 and 33.3% of the farms in operations A and C, respectively. Also, the livability rate of 98% or less was observed in 73.3 and 93.4% of the farms, in operation A and C, respectively, which lower than other operations. Moreover, it was observed that 60.0 and 40.0% of farms in operations B and C reused litter 3 or more times. Among the 74 farms, the most common antimicrobials prescription frequency was 2 times (39.2%), and the prescription to β-lactams antibiotics (45.3%) showed the significantly highest (P < 0.05). The highest administration of antimicrobials was at 15 to 22-days old (42.7%), and most of them were recommended by veterinarian (80.7%). Footbath disinfectant and spraying outside the poultry house were performed in most of the farms (64.9 and 83.8%, respectively), but the use of quicklime (36.5%) and drinking water disinfectant (18.9%) was low in farms. Most of the farms washed vehicles for transportation of poultry (87.8%) and feed (100%) before arriving at the farms, however, 40.5% of the farms used little or no disinfectants when washing the transport vehicles. Moreover, wild birds, and cats and dogs were well controlled on most of the farms (each 94.6%), but only 74.3% of farms offered rodent control programs. Also, only 27.0% of the farms used farm-specific shoes and clothing as well as footbath disinfection for entrance. These findings can be useful in developing policies and guidelines for sustainable and responsible broiler chicken production and reduction of antimicrobial use in Korea.

Rhodococcus Equi: Challenges to Treat Infections and to Mitigate Antimicrobial Resistance.

Rhodococcus equi, a gram-positive facultative intracellular pathogen and a soil saprophyte, is one of the most common causes of pneumonia in young foals. It poses a threat to the economy in endemic horse-breeding farms and to animal welfare annually. Many farms use thoracic ultrasonographic screening and antimicrobial treatment of subclinically affected foals as a preventive measure against severe R. equi infections. The wide use antimicrobials to treat subclinically affected foals has contributed to the emergence of multidrug resistant (MDR)-R. equi in both clinical isolates from sick foals and in the environment of horse-breeding farms. Alternatives to treat foals infected with MDR-R. equi are scarce and the impact of the emergence of MDR-R. equi in the environment of farms is still unknown. The aim of this review is to discuss the emergence of MDR-R. equi in the United States and the challenges faced to guide antimicrobial use practices. Reduction of antimicrobial use at horse-breeding farms is essential for the preservation of antimicrobial efficacy and, ultimately, human, animal, and environmental health.

Decrease in the prevalence of antimicrobial resistance in Escherichia coli isolates of Canadian turkey flocks driven by the implementation of an antimicrobial stewardship program.

The emergence of antimicrobial-resistant organisms at the human-animal-environment interface has raised global concern prompting governments and various stakeholders to take action. As a part of the stewardship initiative, Canadian turkey producers have implemented an antimicrobial use (AMU) strategy to manage antimicrobial resistance (AMR) in their sector. This study evaluated farm-level AMU and AMR data collected between 2016 and 2021 in major turkey-producing provinces/regions through the Canadian Integrated Program for Antimicrobial Resistance Surveillance to assess the progress of the strategy by characterizing the prevalence of homologous and multidrug resistance (MDR) in Escherichia coli isolated from turkeys. Multivariable mixed-effect logistic regression models assessed temporal and provincial/regional variations in AMR and MDR. Negative binomial regression models examined the temporal and regional variations in the total AMU. The total AMU (measured in mg/kg turkey biomass) significantly decreased in all provinces/regions in 2020 and 2021. Escherichia coli isolates from turkey flocks showed a significant decrease in resistance to gentamicin, sulfisoxazole, and tetracyclines during the six-year study period, consistent with the timing of the AMU reduction strategy. The prevalence of MDR isolates was significantly lower in 2020 and 2021 compared to 2016. Higher prevalence was observed in the Western region compared to Québec and Ontario. Two common AMR patterns were identified: ampicillin-streptomycin-tetracyclines and streptomycin-sulfisoxazole-tetracyclines. These AMR patterns indicate possible cross-resistances (same class), co-selection (unrelated classes) for resistance, or potential carryover of resistance determinants from previous production cycles. The decreasing prevalence of resistance to homologous antimicrobials, MDR, and AMU quantity are suggestive that the turkey sector's AMU strategy is achieving its desired impact. However, antimicrobials previously eliminated for preventive use in turkey flocks and the use of highly important antimicrobials in human medicine suggest that the AMU reduction strategy should be monitored and re-evaluated periodically to mitigate the emergence of MDR bacteria and safeguard animal and public health.

Impact of antimicrobial use on abundance of antimicrobial resistance genes in chicken flocks in Vietnam.

We investigated longitudinally Vietnamese small-scale chicken flocks in order to characterize changes in antimicrobial resistance gene (ARG) content over their life cycle, and the impact of antimicrobial use (AMU) on an intervention consisting of veterinary advice provision. AMU data and faecal samples were collected from 83 flocks (25 farms) at day-old, mid- and late-production (∼4 month cycle). Using high-throughput real-time PCR, samples were investigated for 94 ARGs. ARG copies were related to 16S rRNA and ng of DNA (ngDNA). Impact of AMU and ARGs in day-olds was investigated by mixed-effects models. Flocks received a mean (standard error, SE) animal daily dose (ADD) of 736.7 (83.0) and 52.1 (9.9) kg in early and late production, respectively. Overall, ARGs/16S rRNA increased from day-old (mean 1.47; SE 0.10) to mid-production (1.61; SE 0.16), further decreasing in end-production (1.60; SE 0.1) (all P > 0.05). In mid-production, ARGs/16S rRNA increased for aminoglycosides, phenicols, sulphonamides and tetracyclines, decreasing for polymyxins β-lactams and genes that confer resistance to mutiple classes (multi-drug resistance) (MDR). At end-production, aminoglycoside resistance decreased and polymyxin and quinolone resistance increased (all P < 0.05). Results in relation to ngDNA gave contradictory results. Neither AMU nor ARGs in day-olds had an impact on subsequent ARG abundance. The intervention resulted in 74.2% AMU reduction; its impact on ARGs depended on whether ARGs/ngDNA (+14.8%) or ARGs/16S rRNA metrics (-10.7%) (P > 0.05) were computed. The flocks' environment (contaminated water, feed and residual contamination) is likely to play a more important role in transmission of ARGs to flocks than previously thought. Results highlight intriguing differences in the quantification of ARGs depending on the metric chosen.

Capturing batching options in pig farms

To achieve ‘all-in/all-out’ pig flow the farm must efficiently batch. A batch is defined as the output from a group of sows from one weaning to another. Batching offers enhancement in the health and pathogen control on the farm. It also has significant social impact on the farm by providing convenient disciplines for the farm staff to follow. With some batching options, it may be possible to move expertise between different farms within a company. The combined benefits boost the wellbeing and welfare of the pigs and farm staff. Reductions in antimicrobial use of 70% have been achieved.

Treatment of mild to moderate clinical bovine mastitis caused by gram-positive bacteria: A noninferiority randomized trial of local penicillin treatment alone or combined with systemic treatment

Bovine mastitis is one of the most important diseases in modern dairy farming, as it leads to reduced welfare and milk production and increased need for antibiotic use. Clinical mastitis in Denmark is most often treated with a combination of local and systemic treatment with penicillin. The objective of this randomized clinical trial was to assess whether worse results could be expected with local intramammary treatment with penicillin compared with a combination of local and systemic treatment with penicillin in terms of the bacteriological cure of mild and moderate clinical mastitis cases caused by gram-positive bacteria. We carried out a noninferiority trial with a noninferiority margin set to a relative reduction in bacteriological cure of 15% between these 2 treatment groups to assess the effect of reducing the total antibiotic use by a factor of 16 for each treated case. Clinical mastitis cases from 12 Danish dairy farms were considered for enrollment. On-farm selection of gram-positive cases was carried out by the farm personnel within the first 24 h after a clinical mastitis case was detected. A single farm used bacterial culture results from the on-farm veterinarian, whereas the other 11 farms were provided with an on-farm test to distinguish gram-positive bacteria from gram-negative or samples without bacterial growth. Cases with suspected gram-positive bacteria were allocated to a treatment group: either local or combination. Bacteriological cure was assessed based on the bacterial species identified in the milk sample from the clinical mastitis case and 2 follow-up samples collected approximately 2 and 3 wk after ended treatment. Identification of bacteria was carried out using MALDI-TOF on bacterial culture growth. Noninferiority was assessed using unadjusted cure rates and adjusted cure rates from a multivariable mixed logistic regression model. Of the 1,972 clinical mastitis cases registered, 345 (18%) met all criteria for inclusion (full data). The data set was further reduced to 265 cases for the multivariable analysis to include only complete registrations. Streptococcus uberis was the most commonly isolated pathogen. Noninferiority was demonstrated for both unadjusted and adjusted cure rates. The unadjusted cure rates were 76.8% and 83.1% for the local and combined treatments, respectively (full data). The pathogen and somatic cell count before the clinical case had an effect on the efficacy of treatment; thus efficient treatment protocols should be herd- and case-specific. The effect of pathogen and somatic cell count on treatment efficacy was similar irrespective of the treatment protocol. We conclude that bacteriological cure of local penicillin treatment for mild and moderate clinical mastitis cases was noninferior to the combination of local and systemic treatment using a 15% noninferiority margin. This suggests that a potential 16-fold reduction in antimicrobial use per mastitis treatment can be achieved with no adverse effect on cure rate.

Characterisation of antimicrobial usage in Danish pigs in 2020.

Denmark is one of the world's largest exporters of pigs and pig meat, so the sector plays an important role in the national antimicrobial use (AMU). The Danish government has run antimicrobial stewardship programs in collaboration with the pig industry for more than 25 years. These have resulted in substantial overall reductions in total AMU and limiting the use of fluoroquinolones, the 3rd and 4th generation cephalosporines and the polymyxin colistin. To understand where further reductions in AMU could take place, it is necessary to investigate which antimicrobials are being used, how, and for which reasons. We characterized the AMU in the Danish pig sector in 2020, providing new analytical insights based on data retrieved from the VetStat database. The AMU data were segmented into classes, routes of administration, treatment indications and age groups, and interpreted as an outcome of the interventions taken. We evaluated the current AMU regarding choice of antimicrobial class. Moreover, we discussed how to further improve the antimicrobial stewardship in Danish pig production to achieve additional reductions without jeopardizing animal welfare. Where relevant, two pig veterinary specialists were consulted. In 2020, 43.3 mg antimicrobials per population correction unit (PCU) were ascribed to the Danish pig sector. There was practically no use of fluoroquinolones, 3rd and 4th generation cephalosporins and polymyxins. Weaners related to 45% of the total AMU in pigs when measured in tonnes and 81% when measured in defined animal daily doses, of these 76% were ascribed to gastrointestinal indications and overall, 83% were administered perorally. To enable further reductions in AMU, it should be investigated how and when to replace group treatments (e.g., all animals in section or a pen) with individual treatments. Moreover, prevention of disease and promotion of animal health should be prioritized, e.g., through focus on feed, vaccination, biosecurity, and disease eradication.