Antibiotic Usage Pattern in Broiler Chicken Flocks in Germany

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.

[Therapy-relevant antibiotic resistances in a One Health context]

One Health refers to a concept that links human, animal, and environmental health. In Germany, there is extensive data on antibiotic resistance (AMR) and multidrug-resistant (micro)organisms (MDRO) in human and veterinary medicine, as well as from studies in various environmental compartments (soil, water, wastewater). All these activities are conducted according to different specifications and standards, which makes it difficult to compare data. A focus on AMR and MDRO of human therapeutic importance is helpful to provide some guidance. Most data are available across sectors on methicillin-resistant Staphylococcus aureus (MRSA) and multiresistant Enterobacterales such as Escherichia coli and Klebsiella pneumoniae. Here, the trends of resistance are heterogeneous. Antibiotic use leads to MRE selection, which is well documented. Success in minimizing antibiotic use has also been demonstrated in recent years in several sectors and could be correlated with success in containing AMR and MDRO (e.g., decrease in MRSA in human medicine). Sector-specific measures to reduce the burden of MDRO and AMR are also necessary, as not all resistance problems are linked to other sectors. Carbapenem resistance is still rare, but most apparent in human pathogens. Colistin resistance occurs in different sectors but shows different mechanisms in each. Resistance to antibiotics of last resort such as linezolid is rare in Germany, but shows a specific One Health correlation. Efforts to harmonize methods, for example in the field of antimicrobial susceptibility testing and genome-based pathogen and AMR surveillance, are an important first step towards a better comparability of the different data collections.

Antimicrobial usage in broiler chicken production in the United States, 2013-2021

Although efforts to improve antimicrobial stewardship should include the collection of antimicrobial use data, most antimicrobial datasets collected at the national level consist of antimicrobial sales data which cannot inform stewardship. These data lack context, such as information regarding target species, disease indication, and regimen specifics like dose, route and duration. Therefore, the goal of this study was to develop a system for collecting data on the use of antimicrobials in the U.S. broiler chicken industry. This study utilized a public-private partnership to enable collection and protection of sensitive data from an extremely large industry while releasing deidentified and aggregated information regarding the details of antimicrobial use on U.S. broiler chicken farms over time. Participation was voluntary. Data were collected for the period 2013 through 2021 and are reported on a calendar year basis. Using production statistics from USDA:NASS as a denominator, the data supplied by participating companies represented approximately 82.1% of broiler chicken production in the U.S. in 2013, approximately 88.6% in 2017, and approximately 85.0% in 2021. The data that were submitted for 2021 are based on approximately 7,826,121,178 chickens slaughtered and 50,550,817,859 pounds liveweight produced. Granular flock-level treatment records were available for 75-90% of the birds represented in the 2018-2021 dataset. There was no use of antimicrobials in the hatchery for the years 2020 and 2021. Medically important in-feed antimicrobial use decreased substantially, with all in-feed tetracycline use being eliminated by 2020, and the use of virginiamycin being reduced by more than 97% since 2013. Medically important water-soluble antimicrobials are used for the treatment of disease in broiler production. Use decreased substantially for most water-soluble antimicrobials. The most important diseases necessitating treatment were necrotic enteritis and gangrenous dermatitis as well as E. coli-related disease. A focus on reducing the incidence of these diseases would reduce the need for antimicrobial therapy but will require an investment in research to find efficacious and cost-effective interventions for these diseases.

One Health Surveillance of Antimicrobial Use and Resistance: Challenges and Successes of Implementing Surveillance Programs in Sri Lanka

Background: Sri Lanka is a low-income country, as defined by the World Bank. The country suffered further economic downturn during the COVID-19 pandemic. This situation adversely affected the prioritization of policies and programs around healthcare and public health. In particular, inflation, fuel prices, and shortage of food supplies increased struggles to implement antimicrobial resistance (AMR) programs. However, in the long run, it is crucial to gather data and evidence to plan AMR policies and track interventions. (1) Aim: To establish and reiterate the importance of prioritizing AMR programs in the One Health framework, the Fleming Fellows collected and studied antimicrobial use/consumption (AMU/AMC) and resistance (AMR) in humans, food-producing animals, and the environment. (2) Methods: A systematic and cross-sectional study was conducted between 2019 and 2021. By way of coordinating an AMU/AMC and AMR prevalence study across six agencies from human health and food-producing animal sectors, the authors established a field epidemiology study, laboratory testing, and data processing at their institutions. AMU/AMC patterns were surveyed using questionnaires and interviews, while AMR samples were collected for antibiotic susceptibility tests and genomic tests. Samples were tested for phenotypic and genotypic resistance. (3) Results: In human samples, resistance was highest to beta-lactam antibiotics. In non-human samples, resistance was highest to erythromycin, a highest-priority, critically important antibiotic defined by the World Health Organization. From government records, tylosin was sold the most in the food-producing animal sector. (4) Conclusions: Sri Lanka AMU and AMR trends in human and non-human sectors can be ascertained by a One Health framework. Further coordinated, consistent, and sustainable planning is feasible, and can help implement an AMU/AMR surveillance system in Sri Lanka.

Use of Antimicrobials by Class in Pigs in Germany-A Longitudinal Description Considering Different International Categorisation Systems

Antimicrobial usage in both human and veterinary medicine is considered one of the main drivers of antimicrobial resistance; its reduction poses a serious challenge. To analyse the associations between usage and resistance, data from monitoring systems and classification of all antimicrobial substances are crucial. In this analysis, we investigated longitudinal data collected between 2013 and 2020 within the Veterinary Consumption of Antibiotics project from pig farms in Germany, including all antimicrobial classes, but focusing on critically important antimicrobials: third- and fourth-generation cephalosporins, fluoroquinolones, macrolides, and polymyxins. Analysing the treatment frequency, we found that a reduction in antimicrobial use in all types of pig production has occurred over time, accompanied by a rising percentage of farms without any usage. The lists of the World Health Organisation, World Organisation for Animal Health, and European Medicine Agency classify different antimicrobial substances as critically important. The vast differences between the respective weighted treatment frequencies allocated to the antimicrobials of main interest reflect the huge impact of the three categorisation systems. We concluded that, with the aim of creating national treatment guidelines supporting veterinarians to make treatment decisions, the list of the European Medicine Agency is the most suitable.

Population Pharmacokinetics of Doxycycline, Administered Alone or with N-Acetylcysteine, in Chickens with Experimental Mycoplasma gallisepticum Infection

Mycoplasmosis is a bacterial infection that significantly affects poultry production, and it is often controlled with antibiotics, including doxycycline. The conducted study aimed to determine population pharmacokinetic (PopPk) parameters of doxycycline in healthy (n = 12) and in Mycoplasma gallisepticum-challenged (n = 20) chickens after its oral administration via drinking water at the registered dose rate of 20 mg/kg b.w./24 h for five days, without or with co-administration of N-acetylcysteine (NAC, a dose of 100 mg/kg b.w./24 h) via the feed. Doxycycline concentrations in plasma were analyzed with the LC-MS/MS method. The values of tvV/F and tvke were 4.73 L × kg−1 and 0.154 h−1, respectively, and they showed low BSV. A high BSV of 93.17% was calculated for the value of tlag of 0.8 h, which reflects the inter-individual differences in the water consumption. PTA was computed after Monte Carlo simulation with the registered dose for doxycycline. The target of %fT > MIC ≥ 80% and 100% can be achieved in 90% of the broiler population, after a correction for protein binding, for bacteria with MIC ≤ 0.5 mg × L−1 and 0.25 mg × L−1, respectively. The applied PopPk model did not reveal significant effect of M. gallisepticum infection and co-administration of NAC on pharmacokinetic parameters of doxycycline.

Real-World Data on Antibiotic Group Treatment in European Livestock: Drivers, Conditions, and Alternatives

Major efforts have been made by veterinary professionals to reduce the need for antibiotic use in animals. An online survey launched by the Federation of Veterinarians of Europe (FVE) aimed to gather responses from practicing veterinarians with field experience in metaphylactic livestock group treatment. Only 17% of all veterinarians (n = 183/1087, all species-specific responses merged) applied metaphylactic group treatments to 75% or more of all their treatments. Significantly less metaphylactic group treatments were reported in mixed practices (p = 0.002) and practices specialized in cattle (p < 0.001) as well as small (p = 0.007) and very small practices (p = 0.009). Gram-negative bacteria, mostly composed of Enterobacteriaceae and Pasteurellaceae, were considered by 75.3% (n = 967/1385) as the most devastating bacterial pathogens. Respondents alleged morbidity (20.1%, n = 201/998) and mortality (42.2%, n = 421/998) as major consequences for animal health and welfare if metaphylaxis would be banned. Responding veterinarians pointed towards vaccinations; improved biosecurity, including hygiene measures; and improved herd health management as the three most effective alternative measures to prevent metaphylactic treatment. However, more research is needed on how to implement appropriate alternatives in a holistic hurdle approach. Active support on a national level will be necessary for the development and application of targeted veterinary treatment guidelines for practitioners, which promote the understanding of drivers and include initiation criteria for metaphylactic group treatments in livestock.

Comparison of Consumption Data and Phenotypical Antimicrobial Resistance in E. coli Isolates of Human Urinary Samples and of Weaning and Fattening Pigs from Surveillance and Monitoring Systems in Germany

Antimicrobial resistance (AMR) data from humans are mostly collected from clinical isolates, whereas from livestock data also exist from colonizing pathogens. In Germany, livestock data are collected from clinical and nonclinical isolates. We compared resistance levels of clinical and nonclinical isolates of Escherichia coli from weaning and fattening pigs with clinical outpatient isolates of humans from urban and rural areas. We also studied the association of AMR with available antimicrobial use (AMU) data from humans and pigs. Differences between rural and urban isolates were minor and did not affect the comparison between human and pig isolates. We found higher resistance levels to most antimicrobials in human isolates compared to nonclinical isolates of fattening pigs. Resistance to ampicillin, however, was significantly more frequent in clinical isolates of fattening pigs and in clinical and nonclinical isolates of weaning pigs compared to isolates from humans. The opposite was observed for ciprofloxacin. Co-trimoxazole resistance proportions were higher in clinical isolates of weaning and fattening pigs as compared to isolates from humans. Resistance proportions were higher in clinical isolates than in nonclinical isolates from pigs of the same age group and were also higher in weaner than in fattening pigs. Significant associations of AMU and AMR were found for gentamicin resistance and aminoglycoside use in humans (borderline) and for ampicillin resistance in clinical isolates and penicillin use in fattening pigs. In summary, we found significant differences between isolates from all populations, requiring more detailed analyses supported by molecular data and better harmonized data on AMU and AMR.