Overview of Evidence of Antimicrobial Use and Antimicrobial Resistance in the Food Chain

Comprehensive experimental and computational analysis of endemic Allium tuncelianum: Phytochemical profiling, antimicrobial activity, and In silico studies for potential therapeutic applications

Allium tuncelianum (TG), an endemic garlic species from Tunceli, Turkey, was investigated using a multidisciplinary approach combining experimental and computational methods. Density Functional Theory (DFT) calculations with B3LYP/def2-SVP/def2-TZVP basis sets were employed to analyze electronic properties, reactivity, and stability under gas and ethanol conditions. Headspace/GC-MS identified 10 major components, with diallyl disulfide (48.03 %) and 1-propene (20.72 %) as predominant. Antimicrobial assays revealed potent activity against MRSA, Salmonella paratyphi A, and E. coli, with MIC values as low as 0.063 mg/mL. Antioxidant capacity, evaluated via DPPH, metal chelating, and FRAP assays, showed promising results, with the water extract exhibiting the highest activity (1.74 mg BHT equivalent/mL). DFT and molecular docking studies highlighted key compounds as potential inhibitors of E. coli Gyrase B, with binding energies of -5.68 and -6.07 kcal/mol. ADME predictions indicated favorable drug-like properties, though some compounds showed potential CYP450 interactions and toxicity. This study provides a comprehensive understanding of TG's biochemical profile and therapeutic potential, offering insights for future research and optimization.

Multivariate Approach to Antimicrobial Residue Concentrations in Animal-Derived Products: An Analytical Review

BACKGROUND

Antimicrobial resistance (AMR) represents an alarming global public health concern exacerbated by livestock antibiotic misuse, affecting humans and the environment. However, the precise magnitude of antimicrobial residue concentrations in animal-derived products remains not well understood. This study aimed to quantify antimicrobial residues in animal products through an analytical literature review.

METHODS

This review covered the scientific articles from 1977 to 2020. The antimicrobials were classified according to the European Medicines Agency (EMA) guidelines into four categories. The final database comprised seven qualitative variables (antibiotic, antibiotic class, region, country, decade, EMA category, animal product and animal species) and one quantitative variable (residue concentration recorded as µg/kg). Due to the number of variables involved in the study, a multivariate analysis approach was used using a Factor Analysis of Mixed Data (FAMD) carried out in R.

RESULTS

The highest concentrations of antimicrobial residues were detected in fish samples, followed by egg. Notably, concentrations of ruminant-derived products were lower than to monogastric. β-Lactam was the most prevalent residue followed by aminoglycosides, sulphonamides and quinolones, respectively. Moreover, South America had the highest residues levels, followed by Asia and Europe.

CONCLUSIONS

The multivariate analysis reveals a possible association between the EMA category, animal species, antimicrobial class and animal product. In conclusion, the concentration of antimicrobial residues in products of animal origin depends mainly on their origin (product, species and geographic region), showing the highest concentrations in products derived from fish and poultry.

Synergistic antimicrobial efficacy of phage cocktails and essential oils against Escherichia coli

This study was designed to evaluate the combined antimicrobial activity of selected phage cocktail (MS2+T7 phages) and essential oils (cinnamon, clove, oregano, and thymol) against Escherichia coli ATCC 15597. To select most effective phages, the lytic abilities of individual phages (MS2, phiX174, and T7) and their phage combinations were assessed using the phage spot test and plaque assay at various multiplicity of infections (MOIs) ranging from 0.01 to 100. The inhibitory effectiveness of selected phage combinations (MS2+T7), treated with and without essential oils (cinnamon, clove, oregano, and thymol; 1/2 × MIC each), against E. coli hosts was evaluated at various MOIs of 0, 0.1, and 1. The antimicrobial effect of phage cocktail (MS2+T7) combined with cinnamon (1/2 × MIC) and thymol (1/2 × MIC) were evaluated using time-kill curve assay for 48 h at 37°C. The 48-h treated cells, including the control, cinnamon, thymol, phage cocktail, and cinnamon-phage cocktail, and thymol-phage cocktail, were further tested for relative fitness, and phage mutant frequency assays. The highest lytic activity of MS2 and T7 phages was observed against E. coli (>6 log reduction) at an MOI of 0.1. The phage combination (MS2+T7) was considerably reduced the number of E. coli by 7 logs (p < 0.05). The lytic activity of MS2+T7 was significantly enhanced in the presence of cinnamon, clove, oregano, and thymol (1/2 × MIC each) after 24-h incubation at 37°C. The combinations of cinnamon-phage cocktail and thymol-phage cocktail effectively reduced the numbers of E. coli by more than 5 log CFU/mL compared to the control after 48 h of incubation at 37°C. The lowest relative fitness (<0.5) and mutant frequency (<10 %) were observed for E. coli treated with the combinations. These findings suggest that combining phage cocktails with essential oils can serve as synergistic antimicrobial agents. Consequently, this study provides valuable insights for developing effective phage therapy strategies and ensuring the sustained effectiveness of phage treatments.

Evaluation of Antimicrobial Usage Supply Chain and Monitoring in the Livestock and Poultry Sector of Pakistan

Irrational use of antimicrobials in humans, livestock, and poultry is often cited as the key driver of the accelerated emergence of antimicrobial resistance (AMR) in humans and animals. In Pakistan, the use of antimicrobials in livestock and poultry is not well-regulated, owing to limited and/or ineffective implementation of existing legislations and lack of coordination amongst the key stakeholders. To gather data and information pertinent to the supply chain mapping and the usage of antibiotics in the livestock and poultry sectors of Pakistan, a national workshop for selected influential stakeholders was held in Islamabad, Pakistan during March 2020 to map the supply chain and the usage of antibiotics in the country. Participants from all relevant organizations identified the supply chain and discussed the status, challenges, and the way forward to enhance data collection and monitoring of antimicrobial usage (AMU) in livestock and poultry sectors to contain the emergence of AMR. The pre-workshop questionnaire was designed to gather relevant information on AMU and its distribution among diverse markets and users from the workshop participants, utilizing open-ended questions. A chart depicting the relative magnitude of an antimicrobial use (AMU) supply chain was constructed to illustrate the flow of antimicrobials from import and production to end-use at the farm level. This chart was shared with participants to gather their professional opinions and potential corrections. It also presented a list of agencies and their roles in regulating AMU, along with the types of AMU data available at each level. Specific recommendations were made at the end of the workshop to review and update legislation to cover the entire AMU supply chain, enhance regulations to restrict the use of antimicrobial growth promoters, build an integrated national AMU database system, and raise awareness about the responsible use of antimicrobials in the livestock and poultry sectors. It was concluded that the AMU supply chain in the veterinary sector of Pakistan is fragmented and is co-regulated by various federal and provincial stakeholders. There are some drugs, such as antibiotic growth promoters, which are not regulated at all. The approach and findings from this study can serve as a model to validate the use and management of antibiotics in other, similar countries currently grappling with serious antimicrobial resistance (AMR) crises.

Behavioral and Socio-Economic Determinants of Antimicrobial Resistance in Sub-Saharan Africa: A Systematic Review

Introduction

Antimicrobial resistance (AMR) is currently one of the twenty-first century's biggest threats to public health. Addressing AMR is often operationalized as requiring 'behavior change' of clinicians and patients and improving the drug development pipeline. Few studies and interventions have approached AMR as a challenge fundamentally embedded within the cultural fabric of modern societies and their varied economic, social and political organizations. This systematic review aimed to gather and review the available data on the behavioral and socio-economic determinants of AMR in sub-Saharan Africa (SSA).

Methods

Articles were sourced from PubMed using search terms across five domains: "Antimicrobial resistance", "Sub-Saharan Africa", "Behavioral", "Socio-economic", and specific SSA country names. References were also reviewed for relevant data. This systematic review included original studies published in English between 2015 and 2023, focusing on behavioral and socio-economic factors influencing AMR in human populations in SSA, with AMR as a key outcome.

Results

This systematic review identified 30 studies, with 83% (n=25) focusing on self-medication and antibiotic use practices, 67% (n=20) on healthcare providers' practices and knowledge, and 60% (n=18) on community knowledge and perceptions of AMR while 50% (n=15) of studies explored various socio-economic factors. The common themes that emerged from these studies included inadequate evidence-based prescription practices (63%, n=19), financial barriers to accessing antibiotics (50%, n=15), poor community awareness of AMR (53%, n=16), regulatory challenges in antibiotic sales and distribution (47%, n=14), and healthcare infrastructure limitations, including deficient diagnostic capabilities and antimicrobial stewardship programs (40%, n=12).

Conclusion

This review's findings provide crucial insights into the behavioral and socioeconomic patterns influencing AMR in sub-Saharan African populations. For AMR interventions to be effective, there is a need for a thorough understanding of people's behaviors and practices about AMR knowledge and antimicrobial use which will help in developing more targeted interventions and policies to address inappropriate antimicrobial use and the spread of AMR.

Key farm characteristics associated with the level of antimicrobial use in rosé veal production - A Danish database study

Antimicrobial use (AMU) in veal production is high compared to other bovine production types and has been suggested as an area with potential for AMU reduction. High AMU is a public health concern due to its association with antimicrobial resistance (AMR). Identifying farm characteristics associated with AMU could provide valuable insights for stakeholders seeking to monitor and implement initiatives to reduce AMU. This study aimed at investigating farm characteristics associated with AMU in Danish rosé veal farms, which is the main veal production type in Denmark. The AMU and characteristics included were extracted from two Danish national databases; The Danish Central Husbandry Register (CHR) and the Danish Veterinary Medicines Statistics Program (VetStat). Characteristics included were farm size, mortality, number of suppliers, sites per farm, and farm-level composition of animals with regards to sex and breed. The 118 farms included in the study received 41 % of the total amount of antimicrobials prescribed for Danish calves and young stock in 2020 measured in Animal Daily Doses (ADD). A multivariable linear regression model with the annual average farm-level AMU as outcome was created. AMU was measured as ADD per 100 animals per day (ADD100) and square root-transformed in the model. Increasing farm size and number of suppliers and decreasing proportion of crossbred bulls were found to be significantly associated with higher AMU. However, proportion of crossbred bulls was correlated with proportion of females. Separating the effects of breed and sex was not possible, partly due to the highly summarised data structure. Mortality and number of sites were not significantly associated with AMU. Farms with the type "starter-farms" has previously been shown to have a higher AMU compared to other rosé veal farm types. An important finding in this study was that grouping multiple sites into farms by using ownership data made it possible to summarise AMU for the full line of production from arrival at the veal farm to exit for slaughter. The results and approaches from this paper present an opportunity for repeated evaluation of farm characteristics associated with AMU, which could be used to continuously adapt and target AMU monitoring and control. In addition, it is done on existing surveillance data which keeps the cost of the study low in terms of data collection and data management.

Antimicrobial Resistance Profiles of Escherichia coli Isolated from Food Animal Carcasses During 2010-2023 in South Korea

Antimicrobial-resistant bacterial contamination of meat poses a significant global public health risk. We aimed to determine antimicrobial resistance profiles and trends of Escherichia coli recovered from carcasses of healthy food-producing animals in South Korea during 2010-2023. In total, 4748 E. coli isolates obtained from cattle (n = 1582), pigs (n = 1572), and chickens (n = 1594) were assessed for susceptibility to 12 antimicrobials. Antimicrobial resistance was different among samples. Overall, antimicrobial resistance was high in pigs and chicken carcasses. More than about 80% of isolates from pigs and chickens exhibited resistance to one or more antimicrobials. Among the tested antimicrobials, resistance to ampicillin, chloramphenicol, streptomycin, and tetracycline was significantly higher in pigs and chickens compared with cattle (p < 0.05). Moreover, chicken isolates showed much higher resistance to nalidixic acid and ciprofloxacin than other samples. Resistance to critically important antimicrobials, colistin, remained less than about 1%, while resistance to ceftiofur showed increased trends in pig and chicken samples. Higher multidrug-resistant (MDR) isolates were identified in chickens and pigs compared with cattle (p < 0.05). Furthermore, most MDR patterns include streptomycin and tetracycline resistance. MDR E. coli contaminating meat during slaughter can be transmitted to humans via the food chain. Thus, prudent use of antimicrobials and proper hygienic practices are urgently needed to reduce the risk of transmission.

Exploring the Potential of Chitosan-Phytochemical Composites in Preventing the Contamination of Antibiotic-Resistant Bacteria on Food Surfaces: A Review

The escalating presence of antibiotic-resistant bacteria (ARB) in food systems presents a pressing challenge, particularly in preventing contamination and ensuring food safety. Traditional sanitation methods, such as cooking and chemical disinfectants, provide effective means to reduce ARB, yet there is a growing need for additional preventive measures directly on food surfaces. This review explores the potential of chitosan-phytochemical composites (CPCs) as surface coatings to prevent the initial contamination of food by ARB, thereby offering a novel complementary approach to conventional food safety practices. Chitosan, combined with active plant-derived metabolites (phytochemicals), forms composites with notable antibacterial and antioxidant properties that enhance its protective effects. We examine CPC synthesis methodologies, including chemical modifications, free radical-induced grafting, and enzyme-mediated techniques, which enhance the stability and activity of CPCs against ARB. Highlighting recent findings on CPCs' antibacterial efficacy through minimum inhibitory concentrations (MIC) and zones of inhibition, this review underscores its potential to reduce ARB contamination risks on food surfaces, particularly in seafood, meat, and postharvest products. The insights provided here aim to encourage future strategies leveraging CPCs as a preventative surface treatment to mitigate ARB in food production and processing environments.

Human and Veterinary Medicine Collaboration: Synergistic Approach to Address Antimicrobial Resistance Through the Lens of Planetary Health

Antimicrobial resistance (AMR) represents a critical threat to human, animal, and environmental health, challenging global efforts to maintain sustainable ecosystems and public health systems. In this review, the complex, cross-disciplinary issues of AMR are explored within the framework of planetary health, emphasizing the interconnectedness of human and veterinary medicine with broader environmental and social systems. Specifically, it addresses the social, economic, environmental, and health dimensions of AMR under the planetary health framework. The social aspects consider how public awareness, education, and healthcare practices shape antimicrobial use (AMU) and resistance patterns. The economic impact evaluates the cost burdens of AMR, including healthcare costs, loss of productivity, and the implications for the livestock and food production industries. The environmental dimension highlights the role of pharmaceutical waste, agricultural runoff, and industrial pollution in contributing to the spread of antimicrobials and resistant pathogens in ecosystems. To illustrate these challenges, a comprehensive literature review using the PubMed and Web of Science databases was conducted, identifying 91 relevant articles on planetary health and AMR. In this review, the knowledge from these studies and additional references is integrated to provide a holistic overview of the AMR crisis. By applying the four pillars of planetary health-social, economic, environmental, and health knowledge-in this manuscript, the necessity is underscored of collaborative strategies across human and veterinary medicine to combat AMR. Ultimately, this synergistic approach aims to shape the policies and practices that safeguard public health, protect ecosystems, and promote a sustainable future by implementing antimicrobial stewardship programs and encouraging prudent AMU.

Assessing Illinois companion animal veterinarians' antimicrobial prescription practices and the factors that influence their decisions when treating bacterial infections in dogs and cats

AIMS

Judicious antimicrobial use in companion animal practice is critical for maintaining the effectiveness of antimicrobial agents against bacterial infections and reducing the selection of antimicrobial-resistant bacteria. This study aimed to provide insights into companion animal veterinarians' antimicrobial treatment recommendations for common bacterial infections in dogs and cats and describe the factors influencing their prescription choices.

METHODS AND RESULTS

An online survey using QualtricsXM® software was administered between September and November 2022 to companion animal veterinarians who were Illinois State Veterinary Medical Association members. Descriptive and text analyses were conducted to assess the participants' responses. A total of 78 surveys were included in the analysis. Skin infections were ranked as the most common bacterial infections for which veterinarians prescribed antimicrobial agents, followed by ear, urinary tract, respiratory, and enteric infections. The severity of clinical symptoms and the results of bacterial culture and susceptibility tests were the most influential factors for veterinarians when making antimicrobial prescription choices. Veterinarians were aware of the current antimicrobial prescription guideline recommendations when prescribing antimicrobials empirically to nine hypothetical scenarios of bacterial infections. According to the results of the text analysis that assessed veterinarians' responses to an open-ended question, regarding their challenges when prescribing antimicrobial agents, the pairwise correlation of word frequencies within each response showed the highest correlations between the words 'owner' and 'compliance', 'administration' and 'route', 'cost' and 'culture', and 'patients' and 'acceptance'.

CONCLUSIONS

The study results can support animal health stakeholders in the development of antimicrobial stewardship programmes to promote appropriate antimicrobial use and limit the emergence of antimicrobial resistance.

The contribution of animal antibiotic use to antibiotic resistance in human infections: Panel evidence from Denmark

Antibiotic use (ABU) in animals is postulated to be a major contributor to selection of antibiotic resistance (ABR) which subsequently causes infections in human populations. However, there are few quantifications of the size of this association. Denmark, as a country with high levels of pig production and strong ABR surveillance data, is an ideal case study for exploring this association. This study compiles a dataset on ABU across several animal species and antibiotic classes, and data on the rate of antibiotic resistance (ABR) in humans across key pathogens, in Denmark over time (2010-2020). Panel data regressions (fixed effects, random effects, first difference and pooled ordinary least squares) were used to test the association between the level of ABR in human isolates and the level of ABU in animals. A positive relationship was identified between ABR in humans and ABU in cattle, with some evidence of a positive relationship for poultry and companion animals, and a negative relationship for fish, although the latter is likely driven by confounding factors. When lagging ABU by one year, the effect of ABU in cattle and companion animals remained similar, the effect of ABU in poultry fell in size, and ABU in fish was no longer significant, perhaps due to differences in life cycle length among animal species. Additional covariates were explored, including pet populations, agricultural production and GDP per capita (at purchasing power parity), but these results were limited by the statistical power of the dataset. Under all models, animal ABU determined only a minority of the change in human ABR levels in this context with adjusted R2 ranging from 0.19 to 0.44. This paper supports the role of animal ABU in determining human ABR levels but suggests that, despite comprising a large portion of systemwide ABU, it only explains a minority of the variation. This is likely driven in part by data limitations, and could also be due to a persistence of ABR once resistance has emerged, suggesting a significant role for socioeconomic and transmission factors in bringing ABR down to desirable levels.

A mixed method approach to analysing patterns and drivers of antibiotic use and resistance in beef farms in Argentina

Introduction

Antimicrobial resistance is a challenge to be faced by all livestock sectors; within beef farming, antibiotic use patterns vary by country and management practices. Argentina is a country with high beef production & consumption but limited information surrounding antibiotic use. The aims of this project was to understand how antibiotics are being used across the beef industry in Argentina and exploring drivers of usage.

Methods

Quantitative and qualitative data was collected by: A survey of breeding and feedlot farms including antibiotic use (from purchase data); a detailed analysis of two feedlot farms' therapeutic antibiotic use records; a survey of vets' views on certain antibiotic practices; and a focus group of farmers and vets focusing on wider influences affecting decision making. Antibiotic use data was calculated using mg/population corrected unit (PCU) (ESVAC) and thematic analysis was used to identify drivers of antibiotic use among participants.

Results

The median use across 17 farms that supplied purchase data was 76.52  mg/kg PCU (ESVAC; IQR  =  36.81  mg/kg PCU [ESVAC]). The detailed farm records showed that the largest reason for treatment was group treatments (72.92% of treatments) followed by treatment for respiratory disease (12.75% of treatments). Macrolides accounted for 76.37% of treatments. Nearly half of farms used routine prophylactic treatment for arriving animals (n  =  7/18). The use of quarantine and 'sick pens' were seen as important by surveyed vets with antibiotic prophylaxis and in-feed antibiotics seen as contributors to antibiotic resistance. The focus group highlighted the influence of the economic and political landscape on husbandry practices and the responsibility the farming sector had towards antibiotic stewardship.

Discussion

Overall, Argentine beef feedlots resemble North American beef feedlots in terms of antibiotic practices but with considerably lower usage, with in-feed monensin representing a large proportion of total ABU. The adaptation period presents a challenge to animal health; antibiotics are administered a prophylaxis, metaphylactic and individual treatments depending on farm management practices. Further research into internationally comparable measures of ABU and detailed cost-benefit analysis of practical, on-farm interventions are needed to aid improved antimicrobial stewardship in livestock systems globally.

Microbial Contamination and Antibiotic Resistance in Fresh Produce and Agro-Ecosystems in South Asia-A Systematic Review

Fresh produce prone to microbial contamination is a potential reservoir for antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), posing challenges to food safety and public health. This systematic review aims to comprehensively assess the prevalence of bacterial pathogens and the incidence of ARB/ARGs in fresh produce and agro-ecosystems across South Asia. Twenty-two relevant studies published between 2012 and 2022 from three major scientific databases and the grey literature were identified. The results revealed a wide occurrence of microbial contamination in various types of fresh produce across South Asia, with a predominance of E. coli (16/22), Salmonella spp. (13/22), Staphylococcus spp. (5/22), and Klebsiella spp. (4/22). The agro-ecosystem serves as a complex interface for microbial interactions; studies have reported the prevalence of E. coli (1/4), Salmonella spp. (1/4) and Listeria monocytogenes (1/4) in farm environment samples. A concerning prevalence of ARB has been reported, with resistance to multiple classes of antibiotics. The presence of ARGs in fresh produce underscores the potential for gene transfer and the emergence of resistant pathogens. To conclude, our review provides insights into the requirements of enhanced surveillance, collaborative efforts, implementation of good agricultural practices, and public awareness for food safety and safeguarding public health in the region.

Veterinary Drug Residues in Food Products of Animal Origin and Their Public Health Consequences: A Review

Veterinary medications used for disease treatment and prevention may remain in animal-origin foods, such as milk, eggs, honey and meat, which could pose a risk to the public's health. These drugs come from different groups of drugs, mostly with antibiotic, anti-parasitic or anti-inflammatory actions, in a range of food matrices including milk, meat or egg. This review is intended to provide the reader with a general insight about the current status of veterinary drug residues in food products of animal origin, detection methods and their public health consequences. The discovery of antimicrobials has led to the development of antibiotics for treating and preventing cattle illnesses and encouraging growth. However, the rise of drug resistance has led to increased antibiotic consumption and resistance among microbes in the animal habitat. This resistance can be passed to humans directly or indirectly through food consumption and direct or indirect interaction. Improper and illegal use, inadequate withdrawal periods and environmental contamination from veterinary drugs are reported to be the major causes for the formation of residue in food products of animal origin. The use of veterinary products above or below the advised level may also result in short- or long-term public health issues, such as the creation of resistant strains of micro-organisms, toxicity, allergy, mutagenesis, teratogenicity and carcinogenetic effects. To ensure consumer safety, veterinary drug residues in food must be under control.

Isolation and antimicrobial susceptibility profile of Salmonella species from slaughtered cattle carcasses and abattoir personnel at Dessie, municipality Abattoir, Northeast Ethiopia

BACKGROUND

Antibiotic-resistant Salmonella is one of the main public health concerns in the world. Isolation of Salmonella in abattoirs has been considered the core source of infection in the community from meat. Still, there is limited information on the contamination rate of cattle carcasses.

OBJECTIVE

This study aimed to document the occurrence and antimicrobial susceptibility profile of Salmonella species recovered from cattle carcass and abattoir personnel at Dessie, municipality abattoir, Northeast Ethiopia: METHODS: A total of 336 carcass swabs of abdomen, neck, and hind limb from cattle carcasses and 24 stool samples were collected from abattoir personnel using a systematic sampling method from February to April 2019. The collected samples were transported using Cary-Blair transport media and cultivated on Selenite cysteine F-broth, Brilliant green agar, and Xylose-lysine deoxycholate agar plates to isolate Salmonella species. Gram stain, colony morphology, and biochemical tests were performed to identify the isolated bacteria. An antimicrobial susceptibility test for Salmonella was performed using the Kirby-Bauer Disc Diffusion method. Descriptive statistics; both bivariable and multivariable logistic regression analysis was performed using SPSS version 25 software. P-value < 0.05 at 95% CI was considered statistically significant.

RESULTS

The prevalence of salmonella species was 8%(27/336) from all samples.'The prevalence of Salmonella isolates in cattle carcass and abattoir personnel was 8%(25/312) and 8.3%(2/24) respectively. The antimicrobial test showed that Salmonella species were 100% resistant to ampicillin, 59.3% to trimethoprim-sulfamethoxazole, 59.3% to tetracycline, and 55.6% to amoxicillin/clavulanate. From the total antimicrobial tested bacteria, 81.5%(22/27) were resistant to three and above classes of antibiotics (drug classes). Unwashed knives, carcasses, and hands of butchers during slaughtering were significantly associated (p < 0.05) with Salmonella found in carcasses.

CONCLUSIONS

Salmonella isolation rates from cattle carcasses were high, with the bacteria showing notable resistance to most tested antibiotics. Poor hygiene practices, unsanitized equipment, and unhygienic beef processing were contributing factors.

Progress and Challenges: Implementation of the UK Antimicrobial Resistance National Action Plan 2019-2024 within the Beef Cattle Sub-Sector

The five-year UK antimicrobial resistance (AMR) National Action Plan (NAP) was published in 2019 focusing on reducing the need for, and unintentional exposure to antimicrobials (AMs); optimising the use of AMs; and investing in innovation, supply and access of AMs. This study aimed to evaluate the progress made in the beef cattle sub-sector in addressing specific NAP commitments related to improving animal health and welfare and responsible antimicrobial use (AMU). A thematic analysis was conducted of 21 semi-structured interviews with stakeholders from government organisations, farms, veterinary practices, levy boards and livestock associations. The findings indicate substantial progress, with various initiatives implemented targeting data collection, farmer and veterinarian engagement, and herd health planning. However, there remain a number of challenges and barriers that need to be addressed in order to assess the impacts of these initiatives, such as the availability of AMU and AMR data. Ensuring the adequacy of resources was found to be critical for the sustainability of effective initiatives, considering competing demands on people's time. Additionally, the importance of other outcomes from these initiatives such as developing and strengthening the farmer-veterinarian relationship should not be underestimated since it is fundamental to successfully addressing issues such as AMR.

The Global Rise of ESBL-Producing Escherichia coli in the Livestock Sector: A Five-Year Overview

β-lactam antibiotics are a key element in the treatment of bacterial infections. However, the excessive use of these antibiotics has contributed to the emergence of β-lactam-resistant enterobacteria, including Escherichia coli. One of the main challenges facing the public health sector is antibacterial resistance (ABR), mainly due to limited options in its pharmacological treatment. Currently, extended-spectrum β-lactamases (ESBLs) present an alarming situation, as there is an increase in morbidity and mortality rates, prolonged hospital stays, and increased costs for sanitary supplies, which involve not only humans but also the environment and animals, especially animals destined for food production. This review presents an analysis of the prevalence of ESBL-producing E. coli and its distribution in different animal sources throughout the world, providing an understanding of the association with resistance and virulence genes, as well as perceiving the population structure of E. coli.

Prevalence, pandemic, preventions and policies to overcome antimicrobial resistance

Antimicrobial resistance (AMR) is a growing concern in Asia, and it is essential to understand the prevalence, pandemic, prevention, and policies to overcome it. According to the World Health Organization (WHO), AMR is one of the main causes of death; in 2019, it was linked to 4.95 million fatalities and caused about 1.27 million deaths. A core package of actions has been provided by WHO to help countries prioritize their needs when creating, carrying out, and overseeing national action plans on antimicrobial resistance. Using a people-cantered approach to AMR, the interventions address the needs and obstacles that individuals and patients encounter when trying to obtain healthcare. The people-cantered core package of AMR treatments seeks to improve public and policymakers; awareness and comprehension of AMR by changing the narrative of AMR to emphasize the needs of people and systemic impairments. Additionally, it backs a more comprehensive and programmatic national response to AMR, which emphasizes the value of fair and inexpensive access to high-quality healthcare services for the avoidance, identification, and management of drug-resistant diseases. The report signals increasing resistance to antibiotics in bacterial infections in humans and the need for better data. In conclusion, the prevalence of AMR in Asia is a significant public health concern, and it is crucial to implement policies and interventions to overcome it.

Genomic characterization of carbapenemase-producing Enterobacterales from Dhaka food markets unveils the spread of high-risk antimicrobial-resistant clones and plasmids co-carrying bla NDM and mcr-1.1

Background

The transmission of carbapenemase-producing Enterobacterales (CPE) in the external environment, especially through food, presents a significant public health risk.

Objectives

To investigate the prevalence and genetic characteristics of CPE in food markets of Dhaka, Bangladesh, using WGS.

Methods

CPE isolates were obtained from different food and water samples collected from food markets in the southern part of Dhaka, Bangladesh. The isolates subsequently underwent molecular typing, WGS employing both short- and long-read sequencers, and plasmid analysis.

Results

This study unveiled an extensive spread of CPE, with no significant difference in contamination rates observed in samples (N = 136), including meat (n = 8), fish (n = 5), vegetables (n = 36) or various food-washed water (n = 65) from markets near hospitals or residential areas. Thirty-eight Enterobacterales from 33 samples carried carbapenemase genes (bla NDM-1, -4, -7, bla KPC-2, bla OXA-181 or bla IMI-1). Among these, the high-risk Escherichia coli ST410 clone was the most prevalent and distributed across various locations. Furthermore, the identification of IncHI2 plasmids co-harbouring resistance genes like bla NDM-5 and mcr-1.1, without discernible epidemiological connections, is a unique finding, suggesting their widespread dissemination.

Conclusions

The analysis unveils a dynamic landscape of CPE dissemination in food markets, underscored by the proliferation of novel IncHI2 hybrid plasmids carrying both colistin- and carbapenem-resistance genes. This illuminates the ever-evolving landscape of antimicrobial resistance in Dhaka, urging us to confront its emergent challenges.

Integrative genomics would strengthen AMR understanding through ONE health approach

Emergence of drug-induced antimicrobial resistance (AMR) forms a crippling health and economic crisis worldwide, causing high mortality from otherwise treatable diseases and infections. Next Generation Sequencing (NGS) has significantly augmented detection of culture independent microbes, potential AMR in pathogens and elucidation of mechanisms underlying it. Here, we review recent findings of AMR evolution in pathogens aided by integrated genomic investigation strategies inclusive of bacteria, virus, fungi and AMR alleles. While AMR monitoring is dominated by data from hospital-related infections, we review genomic surveillance of both biotic and abiotic components involved in global AMR emergence and persistence. Identification of pathogen-intrinsic as well as environmental and/or host factors through robust genomics/bioinformatics, along with monitoring of type and frequency of antibiotic usage will greatly facilitate prediction of regional and global patterns of AMR evolution. Genomics-enabled AMR prediction and surveillance will be crucial - in shaping health and economic policies within the One Health framework to combat this global concern.

Salmonella spp. in Domestic Ruminants, Evaluation of Antimicrobial Resistance Based on the One Health Approach-A Systematic Review and Meta-Analysis

Salmonella spp. pose a global threat as a leading cause of foodborne illnesses, particularly prevalent in the European Union (EU), where it remains the second cause of foodborne outbreaks. The emergence of antimicrobial resistance (AMR) in Salmonella spp. has become a critical concern, complicating treatment strategies and escalating the risk of severe infections. The study focuses on large and small ruminants, identifying a prevalence of Salmonella spp. in slaughterhouses and revealing varied AMR rates across antimicrobial families throughout a meta-analysis. Also, comparison with AMR in human medicine was carried out by a systematic review. The results of the present meta-analysis displayed a prevalence of Salmonella spp. in large and small ruminants at slaughterhouses of 8.01% (8.31%, cattle; 7.04%, goats; 6.12%, sheep). According to the AMR of Salmonella spp., 20, 14, and 13 out of 62 antimicrobials studied were classified as low (<5%), high (>5% but <10%), and very high (>10%), respectively. Salmonella spp. did not display AMR against aztreonam, mezlocillin, ertapenem, meropenem, cefoxitin, ceftazidime, levofloxacin, tilmicosin, linezolid, fosfomycin, furazolidone, quinupristin, trimethoprim and spectinomycin. In contrast, a prevalence of 100% of AMR has been described against ofloxacin, lincomycin, and cloxacillin. In the context of the main antibiotics used in the treatment of human salmonellosis, azithromycin was shown to have the highest resistance among Salmonella spp. isolates from humans. Regarding cephalosporins, which are also used for the treatment of salmonellosis in humans, the prevalence of Salmonella spp. resistance to this class of antibiotics was similar in both human and animal samples. Concerning quinolones, despite a heightened resistance profile in Salmonella spp. isolates from ruminant samples, there appears to be no discernible compromise to the efficacy of salmonellosis treatment in humans since lower prevalences of AMR in Salmonella spp. isolated from human specimens were observed. Although the resistance of Salmonella spp. indicates some degree of concern, most antibiotics are not used in veterinary medicine. Thus, the contribution of cattle, sheep and goats to the rise of antibiotic resistance of Salmonella spp. and its potential impact on public health appears to be relatively insignificant, due to their low prevalence in carcasses and organs. Nevertheless, the observed low prevalence of Salmonella spp. in ruminants at slaughterhouse and the correspondingly low AMR rates of Salmonella spp. to key antibiotics employed in human medicine do not indicate that ruminant livestock poses a substantial public health risk concerning the transmission of AMR. Thus, the results observed in both the meta-analysis and systematic review suggests that AMR is not solely attributed to veterinary antibiotic use but is also influenced by factors such as animal health management (i.e., biosecurity measures, prophylactic schemes) and human medicine.

Improvements of weaned pigs barn hygiene to reduce the spread of antimicrobial resistance

The spread of antimicrobial resistance (AMR) in animal husbandry is usually attributed to the use of antibiotics and poor hygiene and biosecurity. We therefore conducted experimental trials to improve hygiene management in weaned pig houses and assessed the impact on the spread. For each of the two groups examined, the experimental group (EG) and the control group (CG), three replicate batches of piglets from the same pig breeder, kept in pre-cleaned flat decks, were analyzed. In the flat decks of the experimental groups, the hygiene conditions (cleaning, disinfection, dust removal and fly control) were improved, while regular hygiene measures were carried out in the control groups. The occurrence and spread of AMR were determined in Escherichia coli (E. coli; resistance indicator) using cultivation-dependent (CFU) and -independent (qPCR) methods as well as whole genome sequencing of isolates in samples of various origins, including feces, flies, feed, dust and swabs. Surprisingly, there were no significant differences (p > 0.05) in the prevalence of resistant E. coli between the flat decks managed with conventional techniques and those managed with improved techniques. Selective cultivation delivered ampicillin- and sulfonamide-resistant E. coli proportions of up to 100% and 1.2%, respectively. While 0.5% E. coli resistant to cefotaxime and no ciprofloxacin resistance were detected. There was a significant difference (p < 0.01) in the abundance of the blaTEM-1 gene in fecal samples between EG and CG groups. The colonization of piglets with resistant pathogens before arrival, the movement of flies in the barn and the treatment of bacterial infections with antibiotics obscured the effects of hygiene improvement. Biocide tolerance tests showed no development of resistance to the farm regular disinfectant. Managing hygiene alone was insufficient for reducing antimicrobial resistances in piglet rearing. We conclude that the complex factors contributing to the presence and distribution of AMR in piglet barns underscore the necessity for a comprehensive management strategy.

Unveiling the landscape of resistance against high priority critically important antimicrobials in food-producing animals across Africa: A scoping review

The rapid population growth in Africa is associated with an increasing demand for livestock products which in turn can lead to antimicrobial use. Antimicrobial usage in animals contributes to the emergence and selection of resistant bacteria which constitutes a serious public health threat. This study aims to review and summarize the available information on highest priority critically important antimicrobials (HPCIAs) resistance in livestock production in Africa. This work will help to inform future policies for controlling antimicrobial resistance (AMR) in the food production chain. A scoping review was conducted according to the Cochrane handbook and following PRISMA 2020 guidelines for reporting. Primary research studies published after 1999 and reporting resistance of Escherichia coli, Enterococcus spp, Staphylococcus aureus, Salmonella spp, and Campylobacter spp to HPCIAs in poultry, cattle, pigs, goats, and sheep in Africa were searched in four databases. A total of 312 articles were included in the review. The majority of the studies (40.7) were conducted in North African countries. More than 49.0% of included studies involved poultry and 26.2% cattle. Cephalosporins and quinolones were the most studied antimicrobial classes. Of the bacteria investigated in the current review, E. coli (41.7%) and Salmonella spp (24.9%) represented the most commonly studied. High levels of resistance against erythromycin in E. coli were found in poultry (MR 96.1%, IQR 83.3-100.0%), cattle (MR 85.7%, IQR 69.2-100.0%), and pigs (MR 94.0%, IQR 86.2-94.0%). In sheep, a high level of resistance was observed in E. coli against nalidixic acid (MR 87.5%, IQR 81.3-93.8%). In goats, the low level of sensibility was noted in S. aureus against streptomycin (MR 86.8%, IQR 19.4-99.0%). The study provides valuable information on HPCIAs resistance in livestock production in Africa and highlights the need for further research and policies to address the public health risk of AMR. This will likely require an investment in diagnostic infrastructure across the continent. Awareness on the harmful impact of AMR in African countries is a requirement to produce more effective and sustainable measures to curb AMR.

Prevalence of knowledge, attitudes, and practices regarding antimicrobial resistance in Africa: a systematic review and meta-analysis

Background

One of the main threats to public health today is antibiotic resistance. This resistance leads to the persistence of infections in the body. It poses an increased risk of transmission to humans and animals through various routes, such as food, water, and the environment.

Objectives

This study aimed to ascertain the overall prevalence of knowledge, attitudes, and practices regarding antimicrobial resistance in Africa.

Methods

A systematic review and meta-analysis of published and unpublished studies was conducted in Africa according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were conducted using appropriate search terms in PubMed, Web of Science, Science Direct, Google Scholar, African Journals Online, and the Cochrane Library. Data were extracted using Microsoft Excel, and STATA version 14 was used for analysis. Publication bias was checked by funnel plot, Egger, and Begg regression tests. A p-value of 0.05 was regarded to indicate potential publication bias. Using I2 statistics, the heterogeneity of the studies was evaluated. Using forest plots, the random effect model was used to present the pooled prevalence with a 95% confidence interval (CI) of meta-analysis.

Results

This review included 39 studies, with 18,769 study participants. Among these 39 studies, 38 were on knowledge assessment, 28 on attitude assessment, and 25 on good practice assessment towards antimicrobial resistances. The overall pooled prevalence level of knowledge regarding antimicrobial resistance in Africa was 55.33% (95% CI: 47.48, 63.18). The overall pooled prevalence of positive attitudes toward antimicrobial resistance in Africa was 46.93% (95% CI: 35.10, 58.76), and the overall pooled prevalence of good practice of antimicrobial resistance in Africa was 51.05% (95% CI: 45.24, 56.87). In addition, sub-group statistical analysis was performed in this meta-analysis, stratified by population sub-region and study design types.

Conclusion

In Africa, the pooled prevalence of knowledge, attitudes, and practices regarding antimicrobial drug resistance among different groups, including the general population, patients, tertiary school students, healthcare workers, and animal owners was found to be low level. Therefore, it is imperative to enhance the education and training programs regarding antibiotic resistance for various groups including the general public, patients, students, healthcare workers, and individuals responsible for the well-being of animals.

Determinants of animal disease and nontherapeutic antibiotic use on smallholder livestock farms

Introduction

Reducing nontherapeutic antibiotic use (ABU) in livestock animals has been identified as an important way of curbing the growth of antimicrobial resistance (AMR). However, nontherapeutic ABU may be important for managing animal disease. In order to reduce nontherapeutic ABU, farmers may need to implement other complementary interventions to safeguard animal health and minimize risk. We should therefore investigate if nontherapeutic ABU is associated with better animal health outcomes before advocating to reduce it. We should also investigate non-antibiotic factors which protect animal health and can make nontherapeutic use less necessary, as well as factors which can encourage farmers to improve their antibiotic stewardship.

Methods

The study investigated these questions using data from the AMUSE survey, which is designed to evaluate knowledge, attitudes and practices relating to AMR in smallholder livestock farms. The sample included 320 animal herds from 216 smallholder livestock farms in Burkina Faso, with livestock species including poultry, small ruminants, and cattle. The determinants of the occurrence of animal disease and nontherapeutic ABU were investigated using binary logistic regression.

Results

Results revealed that nontherapeutic ABU was positively associated with animal disease, although the potential reverse causality of this relationship should be investigated further. Going primarily to a public veterinarian for animal health services, and having a higher level of formal education, were negatively associated with the occurrence of disease. Going primarily to a community animal health worker was positively associated with using antibiotics nontherapeutically, whereas going primarily to a public veterinarian was negatively associated with this outcome. Having an animal health professional (of any kind) provide diagnosis and treatment was positively associated with nontherapeutic antibiotic use for goats and sheep.

Discussion

These findings support the expansion of education access and public veterinary services as a way to encourage better antibiotic stewardship while guarding against any animal health risks associated with doing so. They also highlight that animal health professionals other than public veterinarians may prioritize animal health outcomes over antibiotic stewardship goals.

Assessing the Microbial Quality of Shrimp (Xiphonaeus kroyeri) and Mussels (Perna perna) Illegally Sold in the Vitória Region, Brazil, and Investigating the Antimicrobial Resistance of Escherichia coli Isolates

The consumption of seafood is crucial for food security, but poor hygiene along the food production chain can result in low microbiological quality, posing significant risks for public health and seafood quality. Thus, this study aimed to assess the microbiological quality and antimicrobial sensitivity of E. coli from 69 samples of illegally marketed shrimp and mussels in the Vitória Region, Brazil. These foods exhibited poor microbiological quality due to high counts of mesophilic, psychrotrophic, and enterobacteria microorganisms. While this issue is widespread in this area, shrimp samples displayed higher microbial counts compared to mussels, and fresh mussels had elevated counts of enterobacteria compared to frozen ones. Among the 10 E. coli isolates, none carried the genes blaCTX-M-1, blaCTX-M-2, blaCTX-M-3, blaCTX-M-15, mcr-1, mcr-2, mcr-3, mcr-4, and tet, associated with antibiotic resistance. Phenotypical resistance to tetracycline and fosfomycin was not observed in any isolate, while only 20% demonstrated resistance to ciprofloxacin. Regarding ampicillin and amoxicillin with clavulanic acid, 60% of isolates were resistant, 10% showed intermediate susceptibility, and 30% were sensitive. One isolate was considered simultaneously resistant to β-lactams and quinolones, and none were conserved as ESBL producers. These findings highlight the inherent risks to local public health that arise from consuming improperly prepared seafood in this area.

Why prescribe antibiotics? A systematic review of knowledge, tension, and motivation among clinicians in low-, middle- and high-income countries

Medical professionals such as physicians and veterinarians are responsible for appropriate antimicrobial prescription (AMP) and use. Although seemingly straightforward, the factors influencing antibiotic prescription, a category of antimicrobials, are complex. Many studies have been conducted in the past two decades on this subject. As a result, there is a plethora of empirical evidence regarding the factors influencing clinicians' AMP practices.

AIM

A systematic review of AMR studies on AMP was conducted, condensing findings according to a combination of the Knowledge, Attitude, and Practice (KAP) and Capacity, Opportunity, Motivation-Behavior (COM-B) models. Review findings were then synthesized and analyzed for policy implementation according to the Consolidated Framework for Implementation Research (CFIR).

DESIGN AND METHODOLOGY

A systematic literature review was conducted according to PRISMA guidelines to identify peer-reviewed papers indexed in pre-determined medical science, social sciences, and humanities databases that apply the KAP model in their investigations. Antimicrobial prescription factors were compared and contrasted among low- and middle-income countries (LMICs) and high-income countries (HICs).

FINDINGS

The KAP model is a heuristic and structured framework for identifying and classifying respondents' knowledge. However, other than medical knowledge, factors that influence prescription decision-making can be expanded to include attitudes, perception, personal affinities, professional circumstances, relational pressure, and social norms.

Impact of florfenicol dosing regimen on the phenotypic and genotypic resistance of enteric bacteria in steers

The food animal sector's use of antimicrobials is heavily critiqued for its role in allowing resistance to develop against critically important antimicrobials in human health. The WHO recommends using lower tier antimicrobials such as florfenicol for disease treatment. The primary objective of this study was to assess the differences in resistance profiles of enteric microbes following administration of florfenicol to steers using both FDA-approved dosing regimens and two different detection methods. Our hypothesis was that we would identify an increased prevalence of resistance in the steers administered the repeated, lower dose of florfenicol; additionally, we hypothesized resistance profiles would be similar between both detection methods. Twelve steers were administered either two intramuscular (20 mg/kg q 48 h; n = 6) or a single subcutaneous dose (40 mg/kg, n = 6). Fecal samples were collected for 38 days, and E. coli and Enterococcus were isolated and tested for resistance. Fecal samples were submitted for metagenomic sequencing analysis. Metagenomics revealed genes conferring resistance to aminoglycosides as the most abundant drug class. Most multidrug resistance genes contained phenicols. The genotypic and phenotypic patterns of resistance were not similar between drug classes. Observed increases in resistant isolates and relative abundance of resistance genes peaked after drug administration and returned to baseline by the end of the sampling period. The use of a "lower tier" antimicrobial, such as florfenicol, may cause an increased amount of resistance to critically important antimicrobials for a brief period, but these changes largely resolve by the end of the drug withdrawal period.

Prevalence and characterization of antimicrobial-resistant Escherichia coli in chicken meat from wet markets in Hong Kong

Given the close contact between animals, animal products, and consumers in wet markets, fresh meat products are considered a potential source and disseminator of antimicrobial-resistant (AMR) bacteria near the end of the food chain. This cross-sectional study was conducted to estimate the prevalence of select AMR-E. coli in fresh chicken meat collected from wet markets in Hong Kong and to determine target genes associated with the observed resistance phenotypes. Following a stratified random sampling design, 180 fresh half-chickens were purchased from 29 wet markets across Hong Kong in 2022 and immediately processed. After incubation, selective isolation was performed for extended-spectrum β-lactamase producing (ESBL), carbapenem-resistant (CRE), and colistin-resistant (CSR) E. coli. The bacterial isolates were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Disc Diffusion was used to determine the susceptibility of ESBL- and CRE-E. coli isolates. The broth microdilution method was used to determine the minimum inhibitory concentration of CSR-E. coli. Targeted resistance genes were then detected by PCR. The prevalence of ESBL-E. coli and CSR-E. coli were estimated at 88.8% (95% CI: 83.4-93.1%) and 6.7% (95% CI: 3.5-11.4%), respectively. No CRE-E. coli isolate was detected. The blaCTX-M-1 gene was the most common β-lactamase group in isolated E. coli (80%), followed by blaTEM (63.7%); no blaSHV gene was detected. Forty-five percent of the isolates had blaTEM and blaCTX-M-1 simultaneously. The mcr-1 gene was detected in all 12 CSR isolates. Of 180 meat samples, 59 were from Mainland China, and 121 were locally sourced. There was no statistically significant difference in the prevalence of ESBL- and CSR-E. coli between the two sources. Our findings can be used to inform food safety risk assessments and set the stage for adopting targeted control and mitigation measures tailored to the local wet markets.

Assessment of biofilm, enzyme production and antibiotic susceptibility of bacteria from milk pre- and post-pasteurization pipelines in Algeria

Bacterial biofilm is a major concern of dairy industry due to its association with milk contamination and its derived products. Algerian pasteurized milk shelf-life does not exceed one day, which may reflect the high level of contamination of this product and presence of extracellular enzymes such as lipases and proteases. This work aimed to investigate the microbial biodiversity in milk-processing surfaces of a dairy plant in Algeria. Therefore, stainless steel cylinders were placed in piping system of the dairy system before and after pasteurization of the milk, being removed after 7 days, for biofilm maturation and microorganism isolation and identification by mass spectrometry. Fifty-nine Gram-positive isolates were identified, namely Bacillus altitudinis, Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Bacillus weithenstephanensis, Enterococcus casseliflavus, Enterococcus faecium, and Staphylococcus epidermidis. In addition, twenty-four Gram-negative isolates were identified, namely Acinetobacter schindleri Enterobacter cloacae, Enterobacter xiangfangensis, Leclercia adecarboxylata, and Raoultella ornithinolytica. Bacterial isolates showed ability for production of extracellular enzymes, being 49 % capable of both proteolytic and lipolytic activities. Milk isolates were tested for the ability to form biofilms on stainless steel. The cell numbers recovered on plate count agar plates from stainless steel biofilms ranged from 3.52 to 6.92 log10 CFU/cm2, being the maximum number detected for Enterococcus casseliflavus. Bacterial isolates showed intermediate and/or resistant profiles to multiple antibiotics. Resistance to amoxicillin, cefoxitin and/or erythromycin was commonly found among the bacterial isolates.

Unveiling antimicrobial resistance in Chilean fertilized soils: a One Health perspective on environmental AMR surveillance

Antimicrobial resistance (AMR) poses a significant threat to humans and animals as well as the environment. Within agricultural settings, the utilization of antimicrobial agents in animal husbandry can lead to the emergence of antimicrobial resistance. In Chile, the widespread use of animal-derived organic amendments, including manure and compost, requires an examination of the potential emergence of AMR resulting from their application. The aim of this research was to identify and compare AMR genes found in fertilized soils and manure in Los Andes city, Chile. Soil samples were collected from an agricultural field, comprising unamended soils, amended soils, and manure used for crop fertilization. The selected genes (n = 28) included genes associated with resistance to beta-lactams, tetracyclines, sulfonamides, polymyxins, macrolides, quinolones, aminoglycosides, as well as mobile genetic elements and multidrug resistance genes. Twenty genes were successfully identified in the samples. Tetracycline resistance genes displayed the highest prevalence, followed by MGE and sulfonamides, while quinolone resistance genes were comparatively less abundant. Notably, blaOXA, sulA, tetO, tetW, tetM, aac (6) ib., and intI1, exhibited higher frequencies in unamended soils, indicating their potential persistence within the soil microbiome and contribution to the perpetuation of AMR over time. Given the complex nature of AMR, it is crucial to adopt an integrated surveillance framework that embraces the One Health approach, involving multiple sectors, to effectively address this challenge. This study represents the first investigation of antimicrobial resistance genes in agricultural soils in Chile, shedding light on the presence and dynamics of AMR in this context.

How farm practices and antibiotic use drive disease incidence in smallholder livestock farms: Evidence from a survey in Uganda

Background

Antimicrobial resistance (AMR) is a growing threat to human and animal health, and the growth in AMR prevalence globally is thought to be partially driven by non-therapeutic antibiotic use in livestock production. However, livestock farms may depend on antibiotics as a prophylactic disease management tool, and reducing antibiotic use in isolation may harm farmers' economic security. In order to help farmers safely reduce their antibiotic use, we must first determine how necessary non-therapeutic antibiotic use is for disease management, and how other farm practices can guard against disease and make antibiotic use reduction safe and feasible.

Methods

Using the Antimicrobial Use in Livestock Production Settings (AMUSE) tool, a standardised survey tool for investigating attitudes and practices relating to antibiotic use on farms, we investigated the farming practices and animal disease outcomes of smallholder livestock farms in Uganda. We used logistic regression to investigate the effect of prophylactic antibiotic use; as well as of prophylactic vaccination, non-antimicrobial medicines, and on-farm biosecurity measures; on the likelihood of disease outbreaks.

Findings

We found that prophylactic antibiotic use did indeed seem to guard against disease outbreaks, underlining the rationality of non-therapeutic antibiotic use in smallholder livestock farms and the need to pair antibiotic use reduction with other interventions in order to mitigate risk. The most effective intervention pairing varied by species, with expanded access to animal health services and the use of prophylactic vaccination demonstrating the greatest potential overall.

Implications

These findings echo earlier results generated using the AMUSE survey tool. They should be followed by participatory research in which farmers are consulted to explore intervention options, and subsequently by farm-level intervention trials of combined antimicrobial stewardship interventions to verify their effectiveness.

Two-Dose Ceftiofur Treatment Increases Cephamycinase Gene Quantities and Fecal Microbiome Diversity in Dairy Cows Diagnosed with Metritis

Antimicrobial resistance is a significant concern worldwide; meanwhile, the impact of 3rd generation cephalosporin (3GC) antibiotics on the microbial communities of cattle and resistance within these communities is largely unknown. The objectives of this study were to determine the effects of two-dose ceftiofur crystalline-free acid (2-CCFA) treatment on the fecal microbiota and on the quantities of second-and third-generation cephalosporin, fluoroquinolone, and macrolide resistance genes in Holstein-Friesian dairy cows in the southwestern United States. Across three dairy farms, 124 matched pairs of cows were enrolled in a longitudinal study. Following the product label regimen, CCFA was administered on days 0 and 3 to cows diagnosed with postpartum metritis. Healthy cows were pair-matched based on lactation number and calving date. Fecal samples were collected on days 0, 6, and 16 and pooled in groups of 4 (n = 192) by farm, day, and treatment group for community DNA extraction. The characterization of community DNA included real-time PCR (qPCR) to quantify the following antibiotic resistance genes: blaCMY-2, blaCTX-M, mphA, qnrB19, and the highly conserved 16S rRNA back-calculated to gene copies per gram of feces. Additionally, 16S rRNA amplicon sequencing and metagenomics analyses were used to determine differences in bacterial community composition by treatment, day, and farm. Overall, blaCMY-2 gene copies per gram of feces increased significantly (p ≤ 0.05) in the treated group compared to the untreated group on day 6 and remained elevated on day 16. However, blaCTX-M, mphA, and qnrB19 gene quantities did not differ significantly (p ≥ 0.05) between treatment groups, days, or farms, suggesting a cephamycinase-specific enhancement in cows on these farms. Perhaps unexpectedly, 16S rRNA amplicon metagenomic analyses showed that the fecal bacterial communities from treated animals on day 6 had significantly greater (p ≤ 0.05) alpha and beta diversity than the untreated group. Two-dose ceftiofur treatment in dairy cows with metritis elevates cephamycinase gene quantities among all fecal bacteria while paradoxically increasing microbial diversity.

Sequencing-based analysis of the microbiomes of Spanish food processing facilities reveals environment-specific variation in the dominant taxa and antibiotic resistance genes

In the last years, advances in high throughput sequencing technologies have opened the possibility to broaden environmental monitoring activities in facilities processing food, offering expanded opportunities for characterizing in an untargeted manner the microbiome and resistome of foods and food processing environments (FPE) with huge potential benefits in food safety management systems. Here the microbiome and resistome of FPE from slaughterhouses (n = 3), dairy (n = 12) and meat (n = 10) processing plants were assessed through whole metagenome sequencing of 2 composite samples for each facility, comprising 10 FPE swabs taken from food contact surfaces and 10 FPE samples from non-food contact surfaces, respectively. FPE from slaughterhouses had more diverse microbiomes and resistomes, while FPE from dairy processing plants showed the highest β-dispersion, consistent with a more heterogeneous microbiome and resistome composition. The predominant bacterial genera depended on the industry type, with Pseudomonas and Psychrobacter being highly dominant in surfaces from slaughterhouses and meat industries, while different lactic acid bacteria predominated in dairy industries. The most abundant antimicrobial resistance genes (ARG) found were associated with resistance to aminoglycosides, tetracyclines and quaternary ammonium compounds (QAC). ARGs relating to resistance to aminoglycosides and tetracyclines were significantly more prevalent in slaughterhouses than in food processing plants, while QAC resistance genes were particularly abundant in some food contact surfaces from dairy and meat processing plants, suggesting that daily sanitation under suboptimal conditions may be selecting for persistent microbiota tolerant to these biocides in some facilities. The taxonomic mapping of ARG pointed to specific bacterial genera, such as Escherichia, Bacillus, or Staphylococcus, as carriers of the most relevant resistance determinants. About 63% of all ARG reads were assigned to contigs classified as plasmid-associated, indicating that the resistome of FPE may be strongly shaped through the spread of mobile genetic elements. Overall, the relevance of FPE as reservoirs of ARG was confirmed and it was demonstrated that next generation sequencing technologies allowing a deep characterisation of sources and routes of spread of microorganisms and antimicrobial resistance determinants in food industry settings hold promise to be integrated in monitoring and food safety management programmes.

Antibacterial Activity of Quinoline-Based Derivatives against Methicillin-Resistant Staphylococcus aureus and Pseudomonas aeruginosa: Design, Synthesis, DFT and Molecular Dynamic Simulations

Bacterial virulence becomes a significant challenge for clinical treatments, particularly those characterized as Multi-Drug-Resistant (MDR) strains. Therefore, the preparation of new compounds with active moieties could be a successful approach for eradication of MDR strains. For this purpose, newly synthesized quinoline compounds were prepared and tested for their antimicrobial activity against Methicillin-Resistant Staphylococcus Aureus (MRSA) and Pseudomonas Aeruginosa (PA). Among the synthesized derivatives, compounds 1-(quinolin-2-ylamino)pyrrolidine-2,5-dione (8) and 2-(2-((5-methylfuran-2-yl)methylene)hydrazinyl)quinoline (12) were shown to possess the highest antimicrobial activity with the minimum inhibitory concentration with the values of 5±2.2 and10±1.5 μg/mL towards Pseudomonas aeruginosa without any activity towards MRSA. Interestingly, compounds 2-(2-((1H-indol-3-yl)methylene)hydrazinyl)quinoline (13) and 2-(4-bromophenyl)-3-(quinolin-2-ylamino)thiazolidin-4-one (16c) showed significant inhibition activity against Staphylococcus aureus MRSA and Pseudomonas aeruginosa. Compound 13 (with indole moiety) particularly displayed excellent bactericidal activity with low MIC values 20±3.3 and 10±1.5 μg/mL against Staphylococcus aureus MRSA and Pseudomonas aeruginosa, respectively. Effects molecular modelling was used to determine the mode of action for the antimicrobial effect. The stability of complexes formed by docking and target-ligand pairing was evaluated using molecular dynamics simulations. The compounds were also tested for binding affinity to the target protein using MM-PBSA. Density-functional theory (DFT) calculations were also used to investigate the electrochemical properties of various compounds.

Consumer Preferences and Attitudes towards Antibiotic Use in Food Animals

Antimicrobial resistance (AMR) is one of the major challenges faced by society, with the real threat of the failure of many medical procedures. Antibiotics are also used in livestock production and provide a potential pathway to increasing AMR. The central challenge involves ensuring animal health and welfare while securing the long-term effectiveness of antibiotics. This paper reports the results of a survey of 5693 respondents from the customer panels of four major UK supermarkets regarding preferences and attitudes towards antibiotic use in food animals, and their perspectives on how the balance between animal welfare and human benefit can be achieved. The results of these surveys are consistent with those from other countries that found that consumers generally have limited knowledge about antibiotic use in agriculture and AMR, with around 50% responding "don't know" to many questions. There was agreement about the benefits of antibiotics outweighing harm, with 40% agreeing that, overall, the use of antibiotics to treat disease in farm animals delivers more benefit than harm. However, 44% neither agreed nor disagreed, indicating a high level of uncertainty and a situation that is potentially unstable. The seriousness of the AMR challenge is such that continued action for the more discriminating use of antibiotics must continue.

Prevalence of Foodborne Bacterial Pathogens and Antibiotic Resistance Genes in Sweets from Local Markets in Iran

BACKGROUND

This study aimed to investigate the prevalences of some important antibiotic-resistance genes (ARGs) and foodborne bacterial pathogens in sweet samples collected from local markets in Iran.

METHODS

Forty sweet samples were collected. Foodborne pathogens and ARGs were detected in the sweet samples by conventional and multiplex PCR assays using species-specific primers.

RESULTS

Staphylococcus aureus, Cronobacter sakazakii, Shigella spp., Campylobacter jejuni, and Campylobacter coli were detected and identified in 47.5%, 20%, 45%, 5%, and 30% of the sweet samples, respectively. We found S. aureus and Shigella spp. were the most prevalent bacterial pathogens. S. aureus was found to be the most frequent pathogenic bacteria profiled in these samples. We also found a significant correlation between the presence of C. coli and Cr. sakazakii. We detected the blaSHV resistance gene in 97.5% of the sweet samples; however, blaTEM was detected in only one sample (2.5%).

CONCLUSIONS

Regarding these results, we suggest preventive strategies such as implementing automation of food processing; monitoring the personal hygiene and health of food handlers, and testing regularly for antibiotic resistance in raw materials and products.

Unraveling the Role of Metals and Organic Acids in Bacterial Antimicrobial Resistance in the Food Chain

Antimicrobial resistance (AMR) has a significant impact on human, animal, and environmental health, being spread in diverse settings. Antibiotic misuse and overuse in the food chain are widely recognized as primary drivers of antibiotic-resistant bacteria. However, other antimicrobials, such as metals and organic acids, commonly present in agri-food environments (e.g., in feed, biocides, or as long-term pollutants), may also contribute to this global public health problem, although this remains a debatable topic owing to limited data. This review aims to provide insights into the current role of metals (i.e., copper, arsenic, and mercury) and organic acids in the emergence and spread of AMR in the food chain. Based on a thorough literature review, this study adopts a unique integrative approach, analyzing in detail the known antimicrobial mechanisms of metals and organic acids, as well as the molecular adaptive tolerance strategies developed by diverse bacteria to overcome their action. Additionally, the interplay between the tolerance to metals or organic acids and AMR is explored, with particular focus on co-selection events. Through a comprehensive analysis, this review highlights potential silent drivers of AMR within the food chain and the need for further research at molecular and epidemiological levels across different food contexts worldwide.

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.

The effect of antibiotic usage on resistance in humans and food-producing animals: a longitudinal, One Health analysis using European data

This paper estimates the effect of antibiotic usage in humans and food-producing animals on the prevalence of resistance in zoonotic bacteria in both humans and animals. Using comprehensive longitudinal data from annual surveillance reports on resistance and usage in Europe, we find that antibiotic usage in food-producing animals and antibiotic usage in humans are independently and causally related to the prevalence of resistance in both humans and animals. The study considers simultaneous and total usage of antibiotics in humans and food-producing animals to identify the marginal effects and joint effects of usage on resistance of both groups. By employing lagged-dependent variable and fixed-effects specifications, we provide a lower and an upper bound on the effects on resistance. The paper also contributes to the scant literature on how antibiotic use in humans is related to resistance in other animals.

A systematic review and meta-analysis of antimicrobial resistance knowledge, attitudes, and practices: Current evidence to build a strong national antimicrobial drug resistance narrative in Ethiopia

Antimicrobial resistance (AMR) is a silent pandemic that has claimed millions of lives, and resulted in long-term disabilities, limited treatment options, and high economic costs associated with the healthcare burden. Given the rising prevalence of AMR, which is expected to pose a challenge to current empirical antibiotic treatment strategies, we sought to summarize the available data on knowledge, attitudes, and practices regarding AMR in Ethiopia. Articles were searched in international electronic databases. Microsoft Excel spreadsheet and STATA software version 16 were used for data extraction and analysis, respectively. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 checklist was followed. The methodological quality of the studies included was assessed by the Joana Briggs Institute critical appraisal checklists. The random-effect meta-analysis model was used to estimate Der Simonian-Laird's pooled effect. Statistical heterogeneity of the meta-analysis was checked through Higgins and Thompson's I2 statistics and Cochran's Q test. Publication bias was investigated by funnel plots, and the regression-based test of Egger for small study effects with a P value < 0.05 was considered to indicate potential reporting bias. In addition, sensitivity and subgroup meta-analyses were performed. Fourteen studies with a total of 4476 participants met the inclusion criteria. Overall, the pooled prevalence of good AMR knowledge was 51.53% [(95% confidence interval (CI): 37.85, 65.21), I2 = 99.0%, P <0.001]. The pooled prevalence of favorable attitudes and good practices were 63.43% [(95% CI: 42.66, 84.20), I2 = 99.6, P <0.001], and 48.85% [(95% CI: 38.68, 59.01), I2 = 93.1, P <0.001] respectively. In conclusion, there is a significant knowledge and practice gap on AMR among the general public, patients, and livestock producers. As a result, we call for greater educational interventions to raise awareness and build a strong national AMR narrative.

Antimicrobial activity of α-mangostin against Staphylococcus species from companion animals in vitro and therapeutic potential of α-mangostin in skin diseases caused by S. pseudintermedius

Antimicrobial resistance in Staphylococcus species from companion animals is becoming increasingly prevalent worldwide. S. pseudintermedius is a leading cause of skin infections in companion animals. α-mangostin (α-MG) exhibits various pharmacological activities, including antimicrobial activity against G (+) bacteria. This study investigated the antimicrobial activity of α-MG against clinical isolates of Staphylococcus species from companion animals and assessed the therapeutic potential of α-MG in skin diseases induced by S. pseudintermedius in a murine model. Furthermore, the action mechanisms of α-MG against S. pseudintermedius were investigated. α-MG exhibited antimicrobial activity against clinical isolates of five different Staphylococcus species from skin diseases of companion animals in vitro, but not G (-) bacteria. α-MG specifically interacted with the major histocompatibility complex II analogous protein (MAP) domain-containing protein located in the cytoplasmic membrane of S. pseudintermedius via hydroxyl groups at C-3 and C-6. Pretreatment of S. pseudintermedius with anti-MAP domain-containing protein polyclonal serum significantly reduced the antimicrobial activity of α-MG. The sub-minimum inhibitory concentration of α-MG differentially regulated 194 genes, especially metabolic pathway and virulence determinants, in S. pseudintermedius. α-MG in pluronic lecithin organogel significantly reduced the bacterial number, partially restored the epidermal barrier, and suppressed the expression of cytokine genes associated with pro-inflammatory, Th1, Th2, and Th17 in skin lesions induced by S. pseudintermedius in a murine model. Thus, α-MG is a potential therapeutic candidate for treating skin diseases caused by Staphylococcus species in companion animals.

Molecular epidemiology and characterization of antimicrobial-resistant Staphylococcus haemolyticus strains isolated from dairy cattle milk in Northwest, China

Introduction

Non-aureus Staphylococcus (NAS) species are currently the most commonly identified microbial agents causing sub-clinical infections of the udder and are also deemed as opportunistic pathogens of clinical mastitis in dairy cattle. More than 10 NAS species have been identified and studied but little is known about S. haemolyticus in accordance with dairy mastitis. The present study focused on the molecular epidemiology and genotypic characterization of S. haemolyticus isolated from dairy cattle milk in Northwest, China.

Methods

In this study, a total of 356 milk samples were collected from large dairy farms in three provinces in Northwest, China. The bacterial isolation and presumptive identification were done by microbiological and biochemical methods following the molecular confirmation by 16S rRNA gene sequencing. The antimicrobial susceptibility testing (AST) was done by Kirby-Bauer disk diffusion assay and antibiotic-resistance genes (ARGs) were identified by PCR. The phylogenetic grouping and sequence typing was done by Pulsed Field Gel Electrophoresis (PFGE) and Multi-Locus Sequence Typing (MLST) respectively.

Results

In total, 39/356 (11.0%) were identified as positive for S. haemolyticus. The overall prevalence of other Staphylococcus species was noted to be 39.6% (141/356), while the species distribution was as follows: S. aureus 14.9%, S. sciuri 10.4%, S. saprophyticus 7.6%, S. chromogenes 4.2%, S. simulans 1.4%, and S. epidermidis 1.1%. The antimicrobial susceptibility of 39 S. haemolyticus strains exhibited higher resistance to erythromycin (92.3%) followed by trimethoprim-sulfamethoxazole (51.3%), ciprofloxacin (43.6%), florfenicol (30.8%), cefoxitin (28.2%), and gentamicin (23.1%). All of the S. haemolyticus strains were susceptible to tetracycline, vancomycin, and linezolid. The overall percentage of multi-drug resistant (MDR) S. haemolyticus strains was noted to be 46.15% (18/39). Among ARGs, mphC was identified as predominant (82.05%), followed by ermB (33.33%), floR (30.77%), gyrA (30.77%), sul1 (28.21%), ermA (23.08%), aadD (12.82%), grlA (12.82%), aacA-aphD (10.26%), sul2 (10.26%), dfrA (7.69%), and dfrG (5.13%). The PFGE categorized 39 S. haemolyticus strains into A-H phylogenetic groups while the MLST categorized strains into eight STs with ST8 being the most predominant while other STs identified were ST3, ST11, ST22, ST32, ST19, ST16, and ST7.

Conclusion

These findings provided new insights into our understanding of the epidemiology and genetic characteristics of S. haemolyticus in dairy farms to inform interventions limiting the spread of AMR in dairy production.

Antibiotic resistance associated lactic acid cross tolerance in Shiga-toxin producing E. coli

Introduction

The occurrence of antibiotic resistant (ABR) bacteria in foods is a growing public health challenge. We evaluated sanitizer cross-tolerance among ABR Escherichia coli (E. coli) O157:H7 and non-O157:H7 Shiga-toxin producing E. coli (STEC) serogroups. Sanitizer tolerance in STEC could be a public health concern as mitigation strategies against the pathogen might be compromised.

Methods

Resistance to ampicillin and streptomycin were evolved in E. coli serogroups: O157:H7 (H1730, and ATCC 43895), O121:H19 and O26:H11. Resistance to antibiotics was evolved chromosomally through incremental exposure to ampicillin (amp C) and streptomycin (strep C). Transformation using a plasmid was performed to confer resistance to ampicillin to generate amp P strep C.

Results

The minimum inhibitory concentration (MIC) of lactic acid for all strains evaluated was 0.375% v/v. Analysis of bacterial growth parameters in tryptic soy broth amended with 0.0625% v/v, 0.125% v/v, and 0.25% v/v (subMIC) lactic acid indicated that growth correlated positively with the lag phase duration, and negatively with both the maximum growth rate and change in population density for all strains evaluated except for the highly tolerant variant- O157:H7 amp P strep C. Strains O121 NR (non-ABR), O121 amp C, O121 amp P strep C, O157:H7 H1730 amp C and O157:H7 H1730 amp P strep C were not inactivated after exposure to 1% and 2.5% v/v lactic acid for 300 s. No recovery of cells was observed after the strains were exposed to 5% v/v lactic acid for 300 s. ABR strains O157:H7 H1730 amp C and O157: H7 H1730 amp P strep C demonstrated a high tolerance to lactic acid (P ≤ 0.05).

Conclusion

ABR in isolate E. coli O157: H7 H1730 may improve tolerance to lactic acid. Increased tolerance may be discerned by evaluating growth parameters of bacteria in presence of sub-MIC levels of lactic acid.

Antimicrobial use and its association with the isolation of and antimicrobial resistance in Campylobacter spp. recovered from fecal samples from Canadian dairy herds: A cross-sectional study

Campylobacteriosis is one of the most common zoonotic diseases in North America. As opposed to humans, animal infections caused by Campylobacter spp. are often asymptomatic. In this study, data collected through the Canadian Dairy Network for Antimicrobial Stewardship surveillance system were used to determine the proportion of Campylobacter spp. and antimicrobial resistant isolates recovered from dairy cattle herds. Additionally, the association of antimicrobial use (AMU) with fecal carriage and antimicrobial resistance (AMR) of Campylobacter spp. were investigated. Pooled fecal samples from 5 animals from each production phase (pre-weaned calves, post-weaned heifers, lactating cows), and a manure storage sample were collected from 140 dairy herds across Canada. Samples were cultured using selective media, and Campylobacter isolates were speciated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and interpretation was made according to the Clinical and Laboratory Standards Institute. Two multilevel logistic regression models were used to investigate the association between the AMU with the isolation and antimicrobial resistance in Campylobacter spp. Of 560 samples, 63.8% were positive for Campylobacter spp., and 96% of the participating farms had at least one sample source (i.e., calves, heifers, lactating cows, or manure storage) positive for Campylobacter spp. Overall, 54.3% of the Campylobacter spp. isolates were resistant to at least one antimicrobial. Resistance to tetracycline was observed in 49.7% of the Campylobacter spp. isolates, followed by ciprofloxacin (19.9%) and nalidixic acid (19.3%). The proportion of multi-drug resistant (≥3 antimicrobial classes) Campylobacter spp. isolates was low (0.3%); however, 15.6% were resistant to two different classes of antimicrobials. Samples collected from lactating cows, heifers, and manure storage were more likely to be positive for Campylobacter spp. compared to calves. Total AMU was associated with a decreased probability of recovering Campylobacter spp. In addition, AMR to either tetracycline or ciprofloxacin had an interaction with antimicrobial use. The probability of resistance to tetracycline increased for each unit increase in the total AMU (Defined Course Dose/100 animal-years), while the probability of resistance to ciprofloxacin decreased. Campylobacter coli isolates were more likely to be resistant to ciprofloxacin and tetracycline when compared to C. jejuni. Our study demonstrated that Campylobacter spp. is widespread among Canadian dairy farms, and a higher proportion of resistance to tetracycline was identified. The total AMU was associated with increased resistance to tetracycline in Campylobacter spp. isolates; however, for ciprofloxacin the AMU was associated with decreased resistance.

Influence of antibiotic-resistance and exudate on peroxyacetic acid tolerance in O157 and non-O157 Shiga toxin producing E. coli

Shiga toxin producing Escherichia coli (STEC) continues to cause foodborne outbreaks associated with beef and beef products despite consistent use of antimicrobial interventions. In this study, the influence of antibiotic resistance (ABR) in E. coli O157:H7 H1730, O157:H7 43,895, O121:H19 and O26:H11 on tolerance to peroxyacetic acid (PAA) was evaluated. Further, bactericidal concentrations of PAA in the presence of nutrient rich media (Tryptic Soy Broth, TSB and beef exudates) and nutrient deficient media (Sterile Deionized Water, SDW and Phosphate Buffered Saline, PBS) were evaluated for all bacterial strains. Antibiotic resistance to ampicillin (amp C), or ampicillin and streptomycin (amp P strep C) was generated in each bacterial strain through incremental exposure to the antibiotics or by plasmid transformation (n = 12 total strains). The mean bactericidal concentrations of PAA were higher (p ≤ 0.05) in nutrient rich media (205.55 ± 31.11 in beef exudate and 195.83 ± 25.00 ppm in TSB) than in nutrient deficient media (57.91 ± 11.97 ppm in SDW and 56.66 ± 9.56 ppm in PBS). Strain O157: H7 ampP strepC was the most tolerant to PAA (p ≤ 0.05). At 200 ppm in nutrient rich media and 60 ppm in nutrient deficient media, all bacterial strains declined in population to below the limit of detection. Analysis of the beef exudates indicated the presence of diverse amino acids that have been associated with acid tolerance. The results from this study indicate that beef exudates could contribute to acid tolerance and suggest that some STEC bacterial strains with certain ABR profiles might be more tolerant to PAA.

Carbohydrate-active enzymes in animal feed

Considering an ever-growing global population, which hit 8 billion people in the fall of 2022, it is essential to find solutions to avoid the competition between human food and animal feed for croplands. Agricultural co-products have become important components of the circular economy with their use in animal feed. Their implementation was made possible by the addition of exogenous enzymes in the diet, especially carbohydrate-active enzymes (CAZymes). In this review, we describe the diversity and versatility of microbial CAZymes targeting non-starch polysaccharides to improve the nutritional potential of diets containing cereals and protein meals. We focused our attention on cellulases, hemicellulases, pectinases which were often found to be crucial in vivo. We also highlight the performance and health benefits brought by the exogenous addition of enzymatic cocktails containing CAZymes in the diets of monogastric animals. Taking the example of the well-studied commercial cocktail Rovabio™, we discuss the evolution, constraints and future challenges faced by feed enzymes suppliers. We hope that this review will promote the use and development of enzyme solutions for industries to sustainably feed humans in the future.

Antimicrobial stewardship on the dairy: Evaluating an on-farm framework for training farmworkers

Dairy farmworkers are commonly responsible for disease diagnosis and routine treatment decisions for cattle. This highlights the importance of farmworkers' knowledge and skills to successfully implement judicious use of antimicrobials in livestock production systems. The main objectives of this project were to develop and evaluate an on-farm educational program for farmworkers in antimicrobial stewardship in adult dairy cattle. A longitudinal quasi-experimental study design was used, by enrolling 12 conventional dairy farms in the United States (6 in California and 6 in Ohio). Farmworkers responsible for treatment decisions on the farm (n = 25) participated in a didactic and hands-on 12-wk antimicrobial stewardship training program led by the investigators. All antimicrobial stewardship training materials were available in Spanish and English. Interactive short videos with audio were developed to cover the learning objectives for each of the 6 teaching modules: antimicrobial resistance, treatment protocols, visual identification of sick animals, clinical mastitis, puerperal metritis, and lameness. Pre- and post-training assessments were administered using an online training assessment tool to evaluate changes in knowledge and attitudes about antimicrobial stewardship practices. Cluster analysis and multiple correspondence analyses were conducted to evaluate the association among categorical variables for participants' level of change in knowledge and its association with language, farm size, and state. A 32% average increase in knowledge was observed through an assessment conducted after completing the antimicrobial stewardship training, compared with the pre-training assessment. A significant improvement in 7 of 13 attitude questions related to antimicrobial stewardship practices on the farm was observed. Knowledge and attitude scores of participants on antimicrobial stewardship and identification of sick animals significantly improved after completing the antimicrobial stewardship training. The results observed in this study support the relevance of antimicrobial stewardship training programs targeting farmworkers to improve antimicrobial drug use knowledge and skills.

β-Lactam resistance genes present in UK pheasants and red-legged partridges

BACKGROUND

Despite considerable recent reductions in antimicrobial use, the UK gamebird industry continues to struggle with production diseases during the rearing season, necessitating significant antibiotic use. This observational study investigated the presence of genes conferring resistance to β-lactam antibiotics within industry-reared pheasants and red-legged partridges in the UK.

METHODS

DNA was extracted from 60 pooled caecal samples collected from gamebirds at routine postmortem examinations during the rearing season. Genes encoding extended-spectrum β-lactamases (ESBL) were detected by PCR and the corresponding alleles were determined.

RESULTS

Over half (53%) of the samples harboured genes encoding blaTEM resistance, with blaSHV identified in 20% of samples. The blaTEM gene was more common on sites with higher antibiotic use, whereas blaSHV was predominantly found in birds younger than 5 weeks. Genotyping of the identified resistance genes revealed the presence of blaTEM-1 , blaSHV-1 and blaSHV-11 alleles.

LIMITATIONS

This was a small-scale study conducted at four sites in southern England.

CONCLUSION

This is the first report of the presence of ESBL genes in gamebirds, highlighting the need for further research into antimicrobial resistance in UK gamebirds.

Drivers of Antibiotic Use in Semi-Intensive Poultry Farms: Evidence from a Survey in Senegal

Antimicrobial resistance (AMR), the capacity of microbial pathogens to survive in the presence of antimicrobials, is considered one of the greatest threats to human health worldwide and is growing rapidly in importance. AMR is thought to be driven in part by the use of antimicrobials (AMU) in livestock production. AMU reduction in agriculture is therefore important, but doing so may endanger farmers' livelihoods and hamper broader food security. Understanding the drivers for farmers' antibiotics use is essential for designing interventions which avoid harming agricultural output and to safeguard farmers' economic security. In this study, we analyse AMUSE survey data from poultry farmers in Senegal to explore the effects of vaccination, attitudes towards AMR, and biosecurity practices on: AMU, animal mortality, and farm productivity. We found that farmers with more "AMR-aware" attitudes may be less likely to use antibiotics in healthy birds. Stronger on-farm biosecurity was associated with less use of antibiotics in healthy birds, and in some specifications was linked to higher broiler productivity. Vaccination and AMU were both higher in farms with a higher disease prevalence, and both factors appeared conducive to higher broiler productivity. Overall, there is evidence that awareness raising and biosecurity improvements could encourage prudent use of antibiotics, and that biosecurity and vaccination could to some extent replace antibiotic use as productivity-enhancing and disease management tools in broiler farms. Finally, issues of farm antimicrobial stewardship must be considered at the structural level, with farm behaviours contingent on interaction with state and private stakeholders.