Antimicrobial & antiparasitic use and resistance in British sheep and cattle: a systematic review

Small-scale sheep and cattle enterprises in Scotland: Demographics, animal health, and biosecurity

Livestock keepers who operate on a small scale in the United Kingdom are often described as either smallholders or hobby farmers; however, this is not always the case. There is another distinct population in Scotland. The crofting system promotes the preservation of a way of life that is significant to the cultural heritage of Scotland, whilst at the same time utilising and maintaining marginal land that could otherwise be deemed of very low productive value. We developed two cross-sectional questionnaire surveys to gather descriptive data about individuals from two populations (crofters and smallholders) who kept sheep and/or cattle. Our aim was to explore demographics, animal health, husbandry, and biosecurity practices of these two communities, including how they may interact with other livestock sectors. Most respondents in each population kept sheep, with far fewer keeping cattle. There was a distinct geographical difference in the approximate location of respondents' holdings. Movement of sheep was often local, temporary, and exempt from reporting to national databases. Visits from the vet were infrequent, but the vet remained an important source of animal health advice, alongside peer networks. The information from these surveys is valuable because policy decisions taken with predominantly larger, commercial-scale enterprises in mind also frequently apply to small-scale enterprises, even though these smaller enterprises may not have the same opportunity to influence those decisions or implement the requirements. Aspects of agricultural activity and food production at the scale explored in these surveys - including plurality of employment and diversification away from purely agricultural activities - are relevant to the United Nations Sustainable Development Goals of sustainable cities and communities, zero hunger and life on land. In this context, competent authorities should support this type of context-sensitive agriculture, alongside seeking to maintain animal health and welfare standards at the highest possible level on a national scale. Our surveys contribute to improved understanding of how these enterprises function and therefore will support policy makers when considering the breadth of keepers and circumstances affected by rules and regulations governing agriculture.

Prevalence of Antibiotic-Resistant Escherichia coli Isolated from Beef Cattle and Dairy Cows in a Livestock Farm in Yamagata, Japan

Antimicrobials are used on livestock farms to treat and prevent infectious animal diseases and to promote the growth of livestock. We monitored the prevalence of antibiotic-resistant Escherichia coli (AR-EC) isolates from beef cattle (BC) and dairy cows (DCs) on a livestock farm in Yamagata, Japan. Fecal samples from 5 male BC and 10 male DCs were collected monthly from October 2022 to November 2023. In total, 152 and 884 E. coli isolates were obtained from the BC and DC fecal samples, respectively. Notably, 26 (17.1%) and 29 (3.3%) E. coli isolates in the BC and DC groups, respectively, were resistant to at least one antibiotic. The resistance rates to tetracycline, ampicillin, gentamicin, and chloramphenicol of the isolates were significantly higher than those to the other antimicrobials. The tetracycline resistance genes tetA (70.6%) in DCs and tetB (28%) in BC were identified, along with the blaTEM gene in ampicillin-resistant isolates (BC: 84.2%, DCs: 42.8%). Despite significant variations in the monthly detection rates of AR-EC isolated from BC and DCs throughout the sampling period, the judicious use of antimicrobials reduced the occurrence of AR-EC in both BC and DCs, thereby minimizing their release into the environment.

Antibiotic use in the Northern Irish sheep flock: What lessons can be learnt from medicine records and farmer attitudes to improve stewardship of these essential medicines?

Stewardship of antibiotics used in livestock production has come under increasing scrutiny, from both the animal welfare point of view and due to concerns that antibiotic use in livestock may pose a risk to human health through selection pressure to drive development of antibiotic resistant strains of bacteria. Despite this concern, however, antibiotic consumption in the sheep sector is currently poorly described. This study determines the range and quantities of antibiotics used in the Northern Irish (NI) sheep flock as well as exploring drivers for their use. A mixed-methods approach was utilised, with an anonymous online scoping survey, analysis of the medicine records from 52 NI sheep farms and semi-structured interviews undertaken with 27 farmers. Eighteen farmers contributed both records and participated in interviews. Veterinary medicine records were derived from two sources: on-farm medicine books (seven) or veterinary practice sales data (51). As six of these farmers provided information from both sources a total of 52 unique farms participated. Overall, antibiotic use in sheep on the 52 farms sampled was low, with a median value of 11.35 mgPCU-1 (mean 13.63 mgPCU-1, sd 10.7; range 0-45.29 mgPCU-1), with all farms below 50 mgkg-1. Critically important antibiotics accounted for 0.21% of all antibiotics purchased. Lameness was the main driver of antibiotic use identified by this study. Others included a range of prophylactic treatments such as oral antibiotics to prevent watery mouth, injectable antibiotics to prevent abortion and following assisted lambing. Farmers acknowledged some of these uses had become habitual over time. The veterinary medicine sales records demonstrated significant sales of antibiotics not authorised for use in sheep, on an ongoing, rather than case-by-case, basis. Farmers were positive about their veterinarian's ability and knowledge to improve flock welfare and productivity, but were unwilling to pay for this advice. However, veterinarians may have facilitated weak medicine stewardship through a failure to adequately challenge farmers seeking antibiotics. Farmers did not maintain accurate or up-to-date on farm medicine or production records in the majority of cases. Despite this lack of on-farm recording, veterinary sales records can be studied in consultation with farmers to provide veterinarians with a farm-specific insight into antibiotic use and related attitudes and behaviours. Farmers and veterinarians can then identify areas and behaviours to target collaboratively, improving antibiotic and wider medicine stewardship, whilst simultaneously improving flock health and productivity.

Challenges and opportunities for reducing anthelmintic use in ruminant livestock systems: Insights from a sheep farmer survey in France

Today's level of anthelmintic use in livestock production is a major threat to both the livestock industry and the environment. In this context, the research community is looking for ways to equip farmers with preventive and treatment strategies that can decrease livestock-industry dependence on anthelmintics. Production practices for a sustainable control of parasites have been advocated for almost forty years, but farmers' uptake of these practices has been too slow to address the issues at stake. In this paper, we examine the rationales behind the under-adoption of sustainable worm control practices in grassland-based livestock systems. This research builds on 25 semi-structured interviews with dairy sheep farmers in southwestern France. The interview material was analysed via qualitative discourse analysis. We highlight farmers' social representations and rationales underpinning adoption or non-adoption of the 'low anthelmintics use' strategy. We identify six profiles for nematode control according to the way each farmer included treatment and coprology in their on-farm practice. We identify that the low-use strategy has low adoption potential due to its low perceived relative advantage; low perceived trialability; unclear compatibility with previous experiences, needs, and values; and higher complexity than the status quo option. We show that holistic, pro-environmental, and collaborative attitudes are associated with adoption of the low-use strategy. We then discuss ways to improve uptake, such as increased communication, trainings, and farm visits involving farmers, extension agents and veterinarians.

Occurrence, ecology risk assessment and exposure evaluation of 19 anthelmintics in dust and soil from China

In order to fill the blank of domestic research on anthelmintics in dust and soil, 159 paired dust (including indoor and outdoor dust) and soil samples were collected nationwide. All 19 kinds of the anthelmintics were detected in the samples. The total concentration of the target substances in the outdoor dust, indoor dust and soil samples ranged from 1.83 to 1.30 × 10³ ng/g, from 2.99 to 6.00 × 10³ ng/g and from 0.23 to 8.03 × 10² ng/g, respectively. The total concentration of the 19 anthelmintics in northern China were significantly higher than those in southern China in the outdoor dust and soil samples. No significant correlation was found in the total concentration of anthelmintics between the indoor and outdoor dust because of strong human activities interference, however, a significant correlation existed between the outdoor dust and soil samples and between the indoor dust and soil samples. High ecological risk was found at 35% and 28% of all the sampling sites to non-target organisms in the soil respectively for IVE and ABA, and merits further study. The daily anthelmintics intakes were evaluated via ingestion and dermal contact of soil and dust samples for both children and adults. Ingestion was the predominant way for anthelmintics exposure, and the anthelmintics in soil and dust did not pose a health threat to human health at present.

Prevalence of Multidrug-Resistant Bacteria (Enteropathogens) Recovered from a Blend of Pig Manure and Pinewood Saw Dust during Anaerobic Co-Digestion in a Steel Biodigester

South Africa adopts intensive livestock farming, embracing the employment of huge quantities of antibiotics to meet the increased demand for meat. Therefore, bacteria occurring in the animal products and manure might develop antibiotic resistance, a scenario which threatens public health. The study investigated the occurrence of Gram-negative bacteria from eighteen pooled samples withdrawn from a single-stage steel biodigester co-digesting pig manure (75%) and pine wood saw dust (25%). The viable counts for each bacterium were determined using the spread plate technique. The bacterial isolates were characterised based on cultural, morphological and biochemical characteristics, using the Analytical Profile Index 20 e test kit. In addition, isolates were characterised based on susceptibility to 14 conventional antibiotics via the disc diffusion method. The MAR index was calculated for each bacterial isolate. The bacterial counts ranged from 104 to 106 cfu/mL, indicating manure as a potential source of contamination. Overall, 159 bacterial isolates were recovered, which displayed diverse susceptibility patterns with marked sensitivity to amoxicillin (100% E. coli), streptomycin (96.15% for Yersinia spp.; 93.33% for Salmonella spp.) and 75% Campylobacter spp. to nitrofurantoin. Varying resistance rates were equally observed, but a common resistance was demonstrated to erythromycin (100% of Salmonella and Yersinia spp.), 90.63% of E. coli and 78.57% of Campylobacter spp. A total of 91.19% of the bacterial isolates had a MAR index > 0.2, represented by 94 MAR phenotypes. The findings revealed multidrug resistance in bacteria from the piggery source, suggesting they can contribute immensely to the spread of multidrug resistance; thus, it serves as a pointer to the need for the enforcement of regulatory antibiotic use in piggery farms. Therefore, to curb the level of multidrug resistance, the piggery farm should implement control measures in the study area.

Occurrence and Effects of Antimicrobials Drugs in Aquatic Ecosystems

Currently, thanks to the development of sensitive analytical techniques, the presence of different emerging pollutants in aquatic ecosystems has been evidenced; however, most of them have not been submitted to any regulation so far. Among emerging contaminants, antimicrobials have received particular attention in recent decades, mainly due to the concerning development of antibiotic resistance observed in bacteria, but little is known about the toxicological and ecological impact that antimicrobials can have on aquatic ecosystems. Their high consumption in human and veterinary medicine, food-producing animals and aquaculture, as well as persistence and poor absorption have caused antimicrobials to be discharged into receiving waters, with or without prior treatment, where they have been detected at ng-mg L−1 levels with the potential to cause effects on the various organisms living within aquatic systems. This review presents the current knowledge on the occurrence of antimicrobials in aquatic ecosystems, emphasizing their occurrence in different environmental matrixes and the effects on aquatic organisms (cyanobacteria, microalgae, invertebrates and vertebrates).

Antimicrobial Resistance Patterns of Escherichia coli Isolated from Sheep and Beef Farms in England and Wales: A Comparison of Disk Diffusion Interpretation Methods

Little data exist on the levels of antimicrobial resistance from bacteria isolated from British sheep and beef cattle. The aim of this study was to investigate antimicrobial resistance patterns on sheep and beef farms in England and Wales using multiple interpretation methods. Fecal samples (n = 350) from sheep and beef cattle were collected from 35 farms. Disk diffusion antimicrobial susceptibility testing against ten antimicrobials was carried out for 1115 (699 sheep, 416 beef) β-glucuronidase-positive Escherichia coli isolates. Susceptibility was interpreted using clinical breakpoints, which determine clinically resistant bacteria, and epidemiological and livestock-specific cut-off values, which determine microbiological-resistant bacteria (non-wild type). Using livestock-specific cut-off values, a high frequency of wild type for all ten antimicrobials was observed in isolates from sheep (90%) and beef cattle (85%). Cluster analysis was performed to identify patterns in antimicrobial resistance. Interpretation of susceptibility using livestock-specific cut-off values showed a cluster of isolates that were non-wild type to cefotaxime and amoxicillin/clavulanic acid, whereas clinical breakpoints did not. A multilevel logistic regression model determined that tetracycline use on the farm and soil copper concentration were significantly associated with tetracycline non-wild type isolates. The results suggest that using human clinical breakpoints could lead to both the under-reporting and over-reporting of antimicrobial resistance in sheep and beef cattle.

Therapeutic effects of chitosan in veterinary dermatology: A systematic review of the literature

Chitosan is a natural polysaccharide with biocompatibility, biodegradability, nontoxicity, antimicrobial, and hemostatic properties. This biopolymer has been used in different pharmaceutical forms; therefore, it has an attractive potential for dermal applications in veterinary medicine. The aim of this review is to assess the healing potential of chitosan, based on its dermatological effects on animals, to enrich the therapeutic options of veterinary clinicians. A systematic review was conducted based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) strategy, retrieving 1,032 studies and selecting 39 after the inclusion and exclusion criteria were applied. The studies included reports with confirmed positive effects (n = 46/99, 46.5 %) (P < 0.05), with positive effects (n = 49.5/99, 49.5 %), and with no effect (n = 4/99, 4 %); none of the studies reported adverse effects. There is an association between frequency of application and a decrease in healing time (P = 0.038); applying chitosan "every 48-72 hours" was the most recommended frequency (n = 10/19, 52.9 %). Chitosan, when applied to skin lesions on animals, produces positive effects on healing, potentially becoming a safe biomaterial for skin treatments in veterinary practice. As an initial protocol, we suggest applying chitosan every 48-72 hours for at least 2 weeks (7 applications).