Characterisation of antimicrobial usage in Danish pigs in 2020

Association between antimicrobial use levels and meat inspection lesions in Danish finishers

In Denmark, the Yellow Card scheme enforces restrictions on pig herds exceeding official permitted limits for antimicrobial use (AMU). To assess if a Yellow Card is related to poor animal health, we examined the association between AMU and the health status of Danish finishers using meat inspection data as a proxy for pig health. We included meat inspection findings in 10.5 million finishers delivered to 9 Danish abattoirs between 2016 and 2020 from herds classified as having a low, medium, or high AMU (Yellow Card herds). The prevalence of meat inspection findings was calculated and analysed in mixed-effects logistic regression models to determine the associations between each of eight selected lesions and AMU level while also considering the effect of herd size, location (east or west) and herd type (indoor or outdoor). Despite differences in AMU, only minor differences in meat inspection lesions were present. The overall result of the multivariable modelling was that herds with a medium AMU level were associated with the lowest prevalence of meat inspection lesions - observed for five out of the eight lesions investigated. Moreover, large herds were associated with a lower prevalence of meat inspection lesions than small herds - observed for seven out of eight lesions. The prevalence of lung and tail lesions was higher for herds in the western region of Denmark compared to the eastern regions, and the prevalence of tail lesions, arthritis and osteomyelitis was higher in outdoor herds compared to indoor herds. Hence, both a high and a low AMU could be linked with health and welfare issues. The results indicate that the advisory role of the herd veterinarian is pivotal in preventing adverse effects of antimicrobial reduction measures on animal health and welfare, in particular, if the Yellow Card limits are reduced further.

Diseases associated with antimicrobial use in pig farms and risk factors thereof: A cross-sectional study in the Netherlands

BACKGROUND

Current antimicrobial use (AMU) in Dutch pig farms is driven by herd health status, as only therapeutic AMU is permitted. This study focused on weaners and sows with suckling piglets to examine the diseases associated with i) overall AMU (measured in Defined Daily Dosage Animal per year - DDDA/Y), ii) use/not use of specific antimicrobial classes, iii) total consumption of specific antimicrobial classes (in DDDA/Y), and iv) farm characteristics linked to the occurrence of diseases that require AMU.

METHODS

Cross-sectional data on AMU, disease aetiologies for group treatments, and farm characteristics were collected from 154 Dutch pig farms, representing the situation in 2019. Associations between disease occurrence as a predictor and AMU (overall and by antimicrobial class) as an outcome were analyzed using multivariable generalized linear regression models. Subsequently, mixed-effects conditional Random Forest analysis was used to identify farm characteristics associated with these diseases.

RESULTS

Group treatments for musculoskeletal/neurological diseases (MNDs) in suckling piglets, and individual treatments (of unknown aetiology) in sows and suckling piglets, were significantly associated with total AMU there. AMU in weaners was significantly associated with respiratory diseases, MNDs, and individual treatments. Tetracyclines and penicillins were primarily used for respiratory diseases and MNDs in weaners, respectively, and for MNDs in sows and suckling piglets. Having a clear separation between clean and dirty outdoor areas in the farm and using boars from own production for estrus detection were both protective against occurrence of respiratory conditions in weaners, whereas PRRS vaccination in suckling piglets was a risk factor. Streptococcus suis vaccination in sows and fully slatted floors were both risk factors for MNDs in weaners, whereas being an organic farm was protective. Use of disinfecting powders in sows increased MNDs risk in suckling piglets and sows, and a longer lactation period was protective against respiratory diseases and MNDs in weaners.

CONCLUSIONS

Respiratory diseases and MNDs in weaners appeared as the primary aetiologies for antimicrobial group treatments on Dutch pig farms. Prioritizing farm practices that enhance biosecurity and animal welfare is crucial for controlling these diseases and, consequently, reducing AMU.

Global antimicrobial use in livestock farming: an estimate for cattle, chickens, and pigs

Livestock farming substantially contributes to the global economy and food security. However, it poses crucial environmental, animal welfare, and public health challenges. The main objective of this study is to quantify the global antimicrobial use (AMU) in cattle, chicken, and pig farming. This information is important for understanding the potential impact of farm AMU on the emergence and spread of antimicrobial resistance among animals and humans. Using the United States Department of Agriculture Production, Supply, and Distribution and the Food and Agriculture Organization databases, we estimated the total supply of cattle (in heads) and its distribution into four weight categories: calves (26%), cows (41%), heifers (4%), and bulls of more than one year (29%). Similarly, we calculated the total supply of pigs (in heads) and divided it into two weight categories: pigs (96%) and sows (4%). For chickens, we considered one weight category. We attributed to each category a standard weight according to the parameters set by the European Medicines Agency (EMA) to determine the animal biomass at risk of antimicrobial treatment, or population correction unit (PCU). Finally, we estimated the global PCUs and then the global AMU based on the average administered to the three species (in mg of active ingredients per kg PCU). With this method, we estimated a global annual AMU of 76 060 tonnes of antimicrobial active ingredients (2019-2021 average), of which 40 697 tonnes (or 53.5%) for cattle, 4 243 tonnes (or 5.6%) for chickens, and 31 120 tonnes (or 40.9%) for pigs. According to our assessment, global AMU leads to almost 20 000 tonnes less than the previous estimates due to a different evaluation of PCUs. In previous studies, PCUs were calculated on the liveweight at slaughtering of animals, while our method considers the age and sex of animals and their average weight at treatment. Our results are consistent with the World Organization for Animal Health (WOAH) estimate of 76 704 tonnes of veterinary antimicrobials globally consumed in 2018 for the total of food-producing animals (the WOAH estimation is based on sales and import data).

Evaluating the OH-EpiCap tool using the Danish integrated surveillance program for AMU and AMR as a case study

Antimicrobial resistance (AMR) is considered a One Health (OH) challenge, ideally demanding concerted efforts from the animal, human and environmental side. DANMAP, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program, is monitoring AMR and antimicrobial use in animals and humans. OH-EpiCap is an evaluation tool, developed to address essential elements in OH surveillance systems, such as the dimensions of the organization, operational activities and the impact of the surveillance activities. We aimed to evaluate DANMAP using OH-EpiCap and hereby assessed the suitability of OH-EpiCap to evaluate integrated AMR surveillance systems. During the evaluation, the strengths and weaknesses of DANMAP concerning the "OH-ness" of the program were discussed. Furthermore, possible adaptations of the standard operating procedures and governance structure were addressed. Attention was paid to the ability and easiness of DANMAP to cope with current and future challenges connected to integrated AMR surveillance. It was concluded that DANMAP has a strong OH approach covering relevant aspects for humans and animals, whereas environmental aspects are missing. OH-EpiCap proved to be straightforward to use and provided valuable insights. The authors recommend OH-EpiCap to be used by health authorities and stakeholders. It is not suitable for the technical evaluation of a surveillance program.

Origin of Antibiotics and Antibiotic Resistance, and Their Impacts on Drug Development: A Narrative Review

Antibiotics have revolutionized medicine, saving countless lives since their discovery in the early 20th century. However, the origin of antibiotics is now overshadowed by the alarming rise in antibiotic resistance. This global crisis stems from the relentless adaptability of microorganisms, driven by misuse and overuse of antibiotics. This article explores the origin of antibiotics and the subsequent emergence of antibiotic resistance. It delves into the mechanisms employed by bacteria to develop resistance, highlighting the dire consequences of drug resistance, including compromised patient care, increased mortality rates, and escalating healthcare costs. The article elucidates the latest strategies against drug-resistant microorganisms, encompassing innovative approaches such as phage therapy, CRISPR-Cas9 technology, and the exploration of natural compounds. Moreover, it examines the profound impact of antibiotic resistance on drug development, rendering the pursuit of new antibiotics economically challenging. The limitations and challenges in developing novel antibiotics are discussed, along with hurdles in the regulatory process that hinder progress in this critical field. Proposals for modifying the regulatory process to facilitate antibiotic development are presented. The withdrawal of major pharmaceutical firms from antibiotic research is examined, along with potential strategies to re-engage their interest. The article also outlines initiatives to overcome economic challenges and incentivize antibiotic development, emphasizing international collaborations and partnerships. Finally, the article sheds light on government-led initiatives against antibiotic resistance, with a specific focus on the Middle East. It discusses the proactive measures taken by governments in the region, such as Saudi Arabia and the United Arab Emirates, to combat this global threat. In the face of antibiotic resistance, a multifaceted approach is imperative. This article provides valuable insights into the complex landscape of antibiotic development, regulatory challenges, and collaborative efforts required to ensure a future where antibiotics remain effective tools in safeguarding public health.