Antimicrobial Use In Pigs Research Articles

Effect of Live and Fragmented Saccharomyces cerevisiae in the Feed of Pigs Challenged with Mycoplasma hyopneumoniae.

Currently, the responsible use of antimicrobials in pigs has allowed the continuous development of alternatives to these antimicrobials. In this study, we describe the impact of treatments with two probiotics, one based on live Saccharomyces cerevisiae (S. cerevisiae) and another based on fragmented S. cerevisiae (beta-glucans), that were administered to piglets at birth and at prechallenge with Mycoplasma hyopneumoniae. Thirty-two pigs were divided into four groups of eight animals each. The animals had free access to water and food. The groups were as follows: Group A, untreated negative control; Group B, inoculated by nebulization with M. hyopneumoniae positive control; Group C, first treated with disintegrated S. cerevisiae (disintegrated Sc) and inoculated by nebulization with M. hyopneumoniae; and Group D, treated with live S. cerevisiae yeast (live Sc) and inoculated by nebulization with M. hyopneumoniae. In a previous study, we found that on Days 1 and 21 of blood sampling, nine proinflammatory cytokines were secreted, and an increase in their secretion occurred for only five of them: TNF-α, INF-α, INF-γ, IL-10, and IL-12 p40. The results of the clinical evolution, the degree of pneumonic lesions, and the productive parameters of treated Groups C and D suggest that S. cerevisiae has an immunomodulatory effect in chronic proliferative M. hyopneumoniae pneumonia characterized by delayed hypersensitivity, which depends on the alteration or modulation of the respiratory immune response. The data presented in this study showed that S. cerevisiae contributed to the innate resistance of infected pigs.

Identification of resistance genes in the framework of veterinary monitoring

Real-time polymerase chain reaction (PCR-PT) was used to examine 263 environmental samples from animal and poultry facilities, as well as faeces, to determine the genetic determinants of resistance to five classes of antimicrobials such as tetracyclines (tetA, tetO, tetM) fluoroquinolones (qnrS, qnrB) cephalosporins, penicillins (CTX-M-1, CTX-M-9, CMY), polymyxins (mcr-1). 95% of samples tested for AMR showed the presence of resistance genes associated with resistance to at least two classes of these broad-spectrum antibiotics. The level of detection of resistance markers to tetracyclines and fluoroquinolones was the highest. The detection of genetic markers of resistance to most antimicrobials has the following ascending order: sheep → horse → goat → cattle → pig → poultry. Our studies correlate with a trend towards more antimicrobial use in pigs and poultry than in cattle.In samples from environmental objects, the identification of genetic determinants of resistance was comparable to the detection in samples from animals only in poultry houses. In faecal samples, resistance genes were detected two to three times more often than in environmental samples.The study showed which resistance markers are common in the fecal microbiome and environmental samples, and the relative amount and frequency of detection of these markers can serve as a risk assessment parameter for the further spread of antibiotic resistance.

Characterisation of antimicrobial usage in Danish pigs in 2020.

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

Antibiotic Use in European Pig Production: Less Is More.

The goal of this study is to describe the current use of antibiotics in the European pig industry based on an extensive literature review. To achieve this, an overview of results from national (n = 15) and multi-country (n = 2) cross-sectional and longitudinal (n = 2) surveys, which describe antimicrobial use in pigs, is presented. Results are further linked to the outcome of the European Surveillance of Veterinary Antimicrobial Consumption (ESVAC) project. Overall, it was found that weaned piglets received the most antibiotics, followed by suckling piglets resulting in over 80% of the treatments being administered to animals before 10 weeks of age. Furthermore, it was observed that antibiotic use (ABU) was significantly associated across age categories, indicating that farms with a high use in piglets also used more antibiotics in their finishers. This may, among other things, be explained by farmers' habits and behavior. However, above all, the studies showed surprisingly large differences in ABU between the countries. These differences may be related to the differences in disease prevalence and/or differences in the level of biosecurity. However, they may also reflect variations in rules and regulations between countries and/or a difference in attitude towards ABU of farmers and veterinarians that are not necessarily linked to the true animal health situation. Furthermore, it was observed that already a substantial proportion of the European pig production is able to successfully raise pigs without any group treatments, indicating that it is possible to rear pigs without systematic use of antibiotics. Based on the ESVAC data, a decline of 43.2% was observed in sales of antibiotics for animals in Europe between 2011 and 2020. To enable efficient antimicrobial quantification and stewardship, 15 European countries have already established systems for herd level monitoring ABU in pigs.

Antimicrobial use in lactating sows, piglets, nursery, and grower-finisher pigs on swine farms in Ontario, Canada during 2017 and 2018

BackgroundData on antimicrobial use (AMU) in pig production are needed for the development of good antimicrobial stewardship practices to reduce the risk of antimicrobial resistance in bacteria that can cause illness in animals and humans. In Canada, there is a lack of quantitative data on AMU in the farrowing and nursery stages of pig production. This study aimed to determine which antimicrobial active ingredients are currently used in farrowing, nursery, and grower-finisher herds in the province of Ontario, Canada, and to quantify AMU using various metrics. We collected data on herd demographics, biosecurity, health status, and AMU during one production cycle from 25 farrowing and 25 nursery herds in Ontario, between May 2017 and April 2018, and obtained data from 23 Ontario grower-finisher herds during the same time frame from the Public Health Agency’s Canadian Integrated Program for Antimicrobial Resistance Surveillance. We applied frequency measures, and weight-, and dose-based metrics to the data.ResultsIn all pigs, the highest quantity of AMU was administered in-feed. By all routes of administration and compared to other production stages, nursery pigs used more antimicrobials in mg/kg biomass and the number of Canadian defined daily doses per 1000 pig-days (doseCA rate), while grower-finisher pigs used more antimicrobials in total kilograms and the number of Canadian defined daily doses per pig. In suckling pigs in some herds, there was routine disease prevention use of ceftiofur, an antimicrobial active ingredient categorized as very highly important in human medicine by Health Canada. The top antimicrobial used in each stage of pig production often varied by the metric used. There was producer-reported growth promotion use of antimicrobials in suckling and grower-finisher feed.ConclusionsThe results of this study provide a current picture of AMU in pigs in Ontario and can be used as a basis for further research on AMU in farrowing and nursery herds in Canada. Our findings confirm that it would be useful to include farrowing and nursery herds in routine AMU surveillance in Canada. A future analysis using data from this project will examine factors that affect the quantity of AMU.

Distribution, genetic heterogeneity, and antimicrobial susceptibility of Brachyspira pilosicoli in Swiss pig herds

Brachyspira (B.) pilosicoli is a bacterium causing porcine intestinal spirochaetosis, a disease characterized by diarrhoea and depressed growth rates especially in nursery and fattening pigs. Knowledge of the epidemiology and antimicrobial susceptibility of this pathogen is limited. Therefore, the aim of this study was to analyse the distribution, genetic heterogeneity, and antimicrobial susceptibility of B. pilosicoli field isolates from Swiss pig farms. Faecal swabs of 693 animals originating from 156 herds were analysed for the presence of Brachyspira spp. using culture and polymerase chain reaction identification. Further characterisation was performed using multilocus sequence typing (MLST) and broth dilution antimicrobial susceptibility testing. With 52.6% positive herds, B. pilosicoli could be frequently isolated from herds with animals suffering from diarrhoea. In herds with animals without clinical signs of diarrhoea, detection was significantly less frequent with only 10.5% positive herds (p 0.001). Among 80 isolates used for typing, genetic heterogeneity was observed with 44 different sequence types (ST) which often differed from herd to herd. No predominant ST was observed. More than 73.0% of the 41 B. pilosicoli isolates analysed, showed minimal inhibitory concentration values above the wild type cut-off values for lincomycin, tylvalosin and/ or tylosin. For tiamulin, valnemulin and doxycycline, this was the case in 48.8%, 43.9% and 36.6%, respectively. In conclusion, a diverse population of B. pilosicoli exhibited decreased susceptibility to antimicrobials used against Brachyspira infections. Monitoring of resistance in Brachyspira spp. is highly recommended to support targeted use of antimicrobials in pigs.

Plasmid-mediated colistin resistance and ESBL production in Escherichia coli from clinically healthy and sick pigs

This study aimed to determine the percentage of colistin resistant and ESBL-producing Escherichia coli from clinically sick and healthy pigs and understand the molecular mechanisms underlying colistin resistance and ESBL production. A total of 454 E. coli isolates from healthy pigs (n = 354; piglets, n = 83; fattening pigs, n = 142 and sows, n = 100) and sick pigs (n = 100) were examined for antimicrobial susceptibility, chromosomal and plasmid-mediated colistin resistance mechanisms and ESBL genes. The healthy (41%) and sick pig (73%) isolates were commonly resistant to colistin. Three mcr genes including mcr-1 (10.4%), mcr-2 (1.1%) and mcr-3 (45%) were detected, of which mcr-3 was most frequently detected in the healthy (33%) and sick pig (57%) isolates. Coexistence of mcr-1/mcr-3 and mcr-2/mcr-3 was observed in piglets (23%), fattening pig (3.5%) and sick pig (13%) isolates. Three amino acid substitutions including E106A and G144S in PmrA and V161G in PmrB were observed only in colistin-resistant isolates carrying mcr-3. The percentage of ESBL-producing E. coli was significantly higher in the sick pigs (44%) than the healthy pigs (19.2%) (P = 0.00). The blaCTX-M group was most prevalent (98.5%), of which blaCTX-M-14 (54.5%) and blaCTX-M-55 (42.9%) were predominant. The blaTEM-1 (68.8%) and blaCMY-2 (6.3%) genes were identified in ESBL-producers. All ESBL producers were multidrug resistant and the majority from piglets (97%), fattening pigs (77.3%) and sick pigs (82%) carried mcr gene (s). ESBL producers from piglets (n = 5) and sick pig (n = 1) simultaneously transferred blaTEM-1 (or blaCTX-M-55) and mcr-3 to Salmonella. In conclusion, pigs are important reservoirs of colistin-resistant E. coli that also produced ESBLs, highlighting the need for prudent and effective use of antimicrobials in pigs and other food-producing animals.

Determinants for antimicrobial resistance genes in farm dust on 333 poultry and pig farms in nine European countries

Livestock feces with antimicrobial resistant bacteria reaches the farm floor, manure pit, farm land and wider environment by run off and aerosolization. Little research has been done on the role of dust in the spread of antimicrobial resistance (AMR) in farms. Concentrations and potential determinants of antimicrobial resistance genes (ARGs) in farm dust are at present not known. Therefore in this study absolute ARG levels, representing the levels people and animals might be exposed to, and relative abundances of ARGs, representing the levels in the bacterial population, were quantified in airborne farm dust using qPCR. Four ARGs were determined in 947 freshly settled farm dust samples, captured with electrostatic dustfall collectors (EDCs), from 174 poultry (broiler) and 159 pig farms across nine European countries. By using linear mixed modeling, associations with fecal ARG levels, antimicrobial use (AMU) and farm and animal related parameters were determined. Results show similar relative abundances in farm dust as in feces and a significant positive association (ranging between 0.21 and 0.82) between the two reservoirs. AMU in pigs was positively associated with ARG abundances in dust from the same stable. Higher biosecurity standards were associated with lower relative ARG abundances in poultry and higher relative ARG abundances in pigs. Lower absolute ARG levels in dust were driven by, among others, summer season and certain bedding materials for poultry, and lower animal density and summer season for pigs. This study indicates different pathways that contribute to shaping the dust resistome in livestock farms, related to dust generation, or affecting the bacterial microbiome. Farm dust is a large reservoir of ARGs from which transmission to bacteria in other reservoirs can possibly occur. The identified determinants of ARG abundances in farm dust can guide future research and potentially farm management policy.

Geographic Drivers of Antimicrobial Use and Resistance in Pigs in Khon Kaen Province, Thailand.

In Thailand, pig production has increased considerably in the last decades to meet a growing demand for pork. Antimicrobials are used routinely in intensive pig production to treat infections and increase productivity. However, the use of antimicrobials also contributes to the rise of antimicrobial resistance with potential consequences for animal and human health. Here, we quantify the association between antimicrobial use and resistance rates in extensive and intensive farms with a focus on geographic proximity between farm and drugstores. Of the 164 enrolled farms, 79% reported using antimicrobials for disease prevention, treatment, or as a feed additive. Antimicrobial-resistant E. coli were present in 63% of farms. These drugs included critically important antimicrobials, such as quinolones and penicillins. Medium-scale farms with intensive animal production practices showed higher resistance rates than small-scale farms with extensive practices. Farms with drug-resistant Escherichia coli were located closer to drugstores and a had a higher proportion of disease than farms without drug-resistant E. coli. We found no association between the presence of resistance in humans and antimicrobial use in pigs. Our findings call for actions to improve herd health to reduce the need for antimicrobials and systematic training of veterinarians and drugstore owners on judicious use of antimicrobials in animals to mitigate resistance.

Antimicrobial use and resistance in Escherichia coli from healthy food-producing animals in Guadeloupe

BackgroundSelection pressure exerted by use of antibiotics in both human and veterinary medicine is responsible for increasing antimicrobial resistance (AMR). The objectives of this study were to better understand antimicrobial use in pigs, beef cattle, and poultry on farms on Guadeloupe, French West Indies, and to acquire data on AMR in Escherichia coli in these food-producing animals. A cross-sectional survey was conducted at 45 farms on Guadeloupe, and practical use of antimicrobials was documented in declarative interviews between March and July 2018. A total of 216 fecal samples were collected between January 2018 and May 2019, comprising 124 from pigs, 75 from beef cattle, and 17 from poultry litter. E. coli isolates were obtained for further testing by isolation and identification from field samples. Antimicrobial susceptibility testing and screening for blaCTX-M, blaTEM, tetA, and tetB resistance genes by polymerase chain reaction on extracted genomic DNA were performed.ResultsThe study showed rational use of antimicrobials, consisting of occasional use for curative treatment by veterinary prescription. Tetracycline was the most commonly used antimicrobial, but its use was not correlated to E. coli resistance. Extended-spectrum β-lactamase (ESBL) E. coli isolates were detected in 7.3% of pigs, 14.7% of beef cattle, and 35.3% of poultry. blaCTX-M-1 was the predominant gene found in ESBL-E. coli isolates (68.8%), followed by blaCTX-M-15 (31.3%).ConclusionDespite rational use of antimicrobials, the rate of ESBL-E. coli in food-producing animals in Guadeloupe, although moderate, is a concern. Further studies are in progress to better define the genetic background of the ESBL-E. coli isolates.Graphical abstract

Evaluation of the antimicrobial use in pigs in Japan using dosage-based indicators.

The use of antimicrobial agents in food-producing animals may lead to the emergence and spread of antimicrobial resistance in bacteria of animal origin. The use of antimicrobial agents in pigs in 2018 in Japan was evaluated in terms of the weight of active ingredient and number of defined daily doses (DDD), using annual sales data of veterinary antimicrobials sold for use in pigs. In addition, the use of antimicrobial agents in the Japanese pig sector in 2008 to 2017 was evaluated to determine whether or not there were any differences in temporal change pattern by use of different metrics. In 2018, 447 metric tons of active ingredient, corresponding to 77,379 × 106 kg-days (Japanese DDD) and 34,903 × 106 kg-days (European DDD) were sold. The proportion of the sales amount of sulfonamides, trimethoprim and lincosamides to the total sales amount was significantly different depending on the metric used. For most antimicrobial classes, the number of Japanese DDDs was greater than the number of European DDDs. These results indicate that the DDD-based metric, which is more reflective of the selective pressure of antimicrobials, is recommended for use in monitoring the antimicrobial use in pigs in Japan. The differences in the number of Japanese DDDs and European DDDs appear to confirm the need for Japanese DDDs.

Antimicrobial use practices, attitudes and responsibilities in UK farm animal veterinary surgeons

Increasing levels of antimicrobial resistance in human and veterinary medicine have raised concerns around the issue of overprescribing and the indiscriminate use of antimicrobials. Their use in food producing animals is under scrutiny due to the perceived risk from the zoonotic transfer of resistant pathogens from animals to humans. This study aimed to explore UK veterinary surgeons antimicrobial prescribing behaviours, their attitudes to antimicrobial resistance and their perceptions of responsibility of antimicrobial use in pigs through a questionnaire study on a census sample of 261 veterinary surgeons in England, Wales and Scotland who had a clinical caseload which included commercial pigs. The questionnaire had a useable response rate of 34.1% (n = 61/179) in eligible veterinary surgeons.Overall, veterinary surgeons reported personal confidence that their prescribing decisions were responsible however, there was concern that the prescribing behaviours of other veterinary surgeons and physicians in human medicine may be less responsible; a sociological concept known as ‘othering’. In parallel, veterinary surgeons seldom identified that treatment failure was a consequence of antimicrobial resistance in their own clinical caseload, however they considered it an issue for other veterinary surgeons and for human prescribers. Veterinary surgeons consulted a wide spectrum of resources on antimicrobial use in pigs which, on occasion, contained conflicting guidance on what was defined as responsible prescribing. The decision over whether or not to prescribe an antimicrobial was influenced by numerous factors relating to the veterinary surgeons’ experience and the clinical situation presented, but maintaining pig welfare was a high priority. There was a shared desire to seek alternative methods to prevent disease to antimicrobial use, however the use of diagnostics to support prescribing decisions was an infrequently reported behaviour and could play a more significant role in prescriber decisions if more cost effective and rapid tests were available.Future interventions to optimise antimicrobial use in pigs needs to focus on the evolution of antimicrobial use practices in a changing political and scientific landscape whilst also considering individual motivations and justifications for use.

Antimicrobial Resistance in Commensal Escherichia coli Isolated from Pigs and Pork Derived from Farms Either Routinely Using or Not Using In-Feed Antimicrobials.

The aims of this study were (i) to evaluate whether routine in-feed antimicrobial use in pigs or not resulted in differences in antimicrobial resistance (AMR) E. coli at different pig producing stages, and (ii) to determine whether resistant strains were presented in pig meat postslaughter. A total of 300 commensal E. coli isolates were obtained and examined for antibiograms, AMR genes, plasmid replicons, and molecular types. The isolates were from two farms either using (A) or not using in-feed antimicrobials (NA), sampled four times during the production cycle and once postslaughter. E. coli resistant to aminoglycosides containing aadA1, aadA2, and aadB and extended-spectrum beta-lactamase-producing (ESBLP) E. coli containing blaCTX-M-1 were significantly increased in the nursery and growing periods in farm A compared to farm NA. IncI1-Iγ and IncHI2 were common in the nursery period and were shown to transfer blaCTX-M genes by conjugation. ST10 was the most common type only found in live pigs. ST604, ST877, ST1209, and ST2798 ESBLP were found only in live pigs, whereas ST72, ST302, and ST402 ESBLP were found in pig meat.

Optimization of Antimicrobial Treatment to Minimize Resistance Selection.

Optimization of antimicrobial treatment is a cornerstone in the fight against antimicrobial resistance. Various national and international authorities and professional veterinary and farming associations have released generic guidelines on prudent antimicrobial use in animals. However, these generic guidelines need to be translated into a set of animal species- and disease-specific practice recommendations. This article focuses on prevention of antimicrobial resistance and its complex relationship with treatment efficacy, highlighting key situations where the current antimicrobial drug products, treatment recommendations, and practices may be insufficient to minimize antimicrobial selection. The authors address this topic using a multidisciplinary approach involving microbiology, pharmacology, clinical medicine, and animal husbandry. In the first part of the article, we define four key targets for implementing the concept of optimal antimicrobial treatment in veterinary practice: (i) reduction of overall antimicrobial consumption, (ii) improved use of diagnostic testing, (iii) prudent use of second-line, critically important antimicrobials, and (iv) optimization of dosage regimens. In the second part, we provided practice recommendations for achieving these four targets, with reference to specific conditions that account for most antimicrobial use in pigs (intestinal and respiratory disease), cattle (respiratory disease and mastitis), dogs and cats (skin, intestinal, genitourinary, and respiratory disease), and horses (upper respiratory disease, neonatal foal care, and surgical infections). Lastly, we present perspectives on the education and research needs for improving antimicrobial use in the future.

Assessment of the Risk to Public Health due to Use of Antimicrobials in Pigs-An Example of Pleuromutilins in Denmark.

Antibiotic consumption in pigs can be optimized by developing treatment guidelines, which encourage veterinarians to use effective drugs with low probability of developing resistance of importance for human health. In Denmark, treatment guidelines for use in swine production are currently under review at the Danish Veterinary and Food Administration. Use of pleuromutilins in swine has previously been associated with a very low risk for human health. However, recent international data and sporadic findings of novel resistance genes suggest a change of risk. Consequently, a reassessment was undertaken inspired by a risk assessment framework developed by the European Medicines Agency. Livestock-associated methicillin-resistant Staphylococcus aureus of clonal complex 398 (MRSA CC398) and enterococci were identified as relevant hazards. The release assessment showed that the probability of development of pleuromutilin resistance was high in MRSA CC398 (medium uncertainty) and low in enterococci (high uncertainty). A relatively small proportion of Danes has an occupational exposure to pigs, and foodborne transmission was only considered of relevance for enterococci, resulting in an altogether low exposure risk. The human consequences of infection with pleuromutilin-resistant MRSA CC398 or enterococci were assessed as low for the public in general but high for vulnerable groups such as hospitalized and immunocompromised persons. For MRSA CC398, the total risk was estimated as low (low uncertainty), among other due to the current guidelines on prevention of MRSA in place at Danish hospitals, which include screening of patients with daily contact to pigs on admittance. Moreover, MRSA CC398 has a medium human–human transmission potential. For enterococci, the total risk was estimated as low due to low prevalence of resistance, low probability of spread to humans, low virulence, but no screening of hospitalized patients, high ability of acquiring resistance genes, and a limited number of alternative antimicrobials (high uncertainty). This assessment reflects the current situation and should be repeated if pleuromutilin consumption increases substantially, resulting in increased prevalence of mobile, easily transmissible resistance mechanisms. Continuous monitoring of pleuromutilin resistance in selected human pathogens should therefore be considered. This also includes monitoring of linezolid resistance, since resistance mechanisms for pleuromutilins and oxazolidones are often coupled.

Risk factors for oral antimicrobial consumption in Swiss fattening pig farms - a case-control study.

BackgroundAntimicrobial consumption in veterinary medicine is of great importance. Increased awareness by the public and media has led to demands for decreased use of antimicrobials in pigs. This study aimed to identify risk factors for regular oral antimicrobial consumption in Swiss fattening pig farms, and to quantify the amount of antimicrobial active substances administered orally to pigs at the farm level.ResultsA case–control study was performed on 99 fattening farms between May 2014 and January 2015. Seventy-two case farms (with oral group treatment of antimicrobials in at least 50 % of pigs) and 27 control farms (with no regular oral group treatment) were visited once during the study. Data about potential risk factors and antimicrobial consumption were collected by questionnaire. Antimicrobial consumption was recorded and treatment incidence (TI) was calculated for all farms over a one year period. Sulphonamides and tetracyclines were the antimicrobials consumed in the greatest quantity. The median TI for oral antimicrobial use in the case group was 224.7. In the control group, the median TI was 0 for oral antimicrobial use, with values ranging from 0 to 140.1. In a multivariable regression model, seven risk factors associated with regular oral antimicrobial group treatment were identified: mixing pigs from different suppliers within the same pen, absence of a work protocol that ensures treating of healthy pigs before sick pigs, distance to next pig farm < 500 metres, external analysis of production parameters, no availability of dirty visitor boots, the farmer not working on other farms, and no application of homoeopathic agents.ConclusionsThe results of this study point out the importance of increasing farmers’ awareness of good farming practices and biosecurity. Important recommendations for decreasing oral antimicrobial consumption identified by this study include avoiding mixing pigs from different suppliers in the same pen and strictly handling sick pigs after healthy ones. Improvements in these areas could enhance the overall health of pigs and thereby reduce the consumption of antimicrobials on pig farms.

Opinions of Spanish pig producers on the role, the level and the risk to public health of antimicrobial use in pigs

Antimicrobial use is a major driver of antimicrobial resistance and prescribers (physicians and veterinarians) and end users (patients, food producers and pet owners) are the cornerstones of this scenario. Intensive pig farming is a livestock activity that has a high antimicrobial use. This study is based on the opinions of pig producers.The study was done at national level and comprised two independent cross-sectional surveys using a questionnaire-based methodology and face-to-face interviews carried out between April and October, 2010. The collected data, which consisted of opinions of producers on 48 farrow-to-finish farms and 62 finisher farms, showed that, irrespective of farm type, pig producers in Spain have an imperfect knowledge of the main use of antimicrobials. Antimicrobials are perceived as valuable cost-effective tools for animal health and husbandry and there is little concern among pig producers about the harmful effects on public health of on-farm antimicrobial use.

Associations of antimicrobial use with antimicrobial resistance in Campylobacter coli from grow-finish pigs in Japan

To determine associations between antimicrobial use and antimicrobial resistance in Campylobacter coli, 155 isolates were obtained from the feces of apparently healthy grow-finish pigs in Japan. In addition, data on the use of antibiotics collected through the national antimicrobial resistance monitoring system in Japan were used for the analysis. Logistic regression was used to identify risk factors to antimicrobial resistance in C. coli in pigs for the following antimicrobials: ampicillin, dihydrostreptomycin, erythromycin, oxytetracycline, chloramphenicol, and enrofloxacin. The data suggested the involvement of several different mechanisms of resistance selection. The statistical relationships were suggestive of co-selection; use of macrolides was associated with enrofloxacin resistance (OR=2.94; CI95%: 0.997, 8.68) and use of tetracyclines was associated with chloramphenicol resistance (OR=2.37; CI95%: 1.08, 5.19). The statistical relationships were suggestive of cross-resistance: use of macrolides was associated with erythromycin resistance (OR=9.36; CI95%: 2.96, 29.62) and the use of phenicols was associated with chloramphenicol resistance (OR=11.83; CI95%: 1.41, 99.44). These data showed that the use of antimicrobials in pigs selects for resistance in C. coli within and between classes of antimicrobials.

Characteristics of commercial pig farms in Great Britain and their use of antimicrobials

A mail survey of 1889 pig producers in Great Britain with more than 100 sows or more than 1000 pigs was carried out to investigate their use of antimicrobials and...

Risk Factors for Antimicrobial Resistance among FecalEscherichia colifrom Residents on Forty-Three Swine Farms

Fecal Escherichia coli (n = 555) were isolated from 115 residents on 43 farrow-to-finish swine farms to determine the prevalence of antimicrobial resistance and associated risk factors. Susceptibility to 21 antimicrobials was determined and the overall prevalence of antimicrobial resistance was 25.8%. Pair-wise difference in prevalences of resistance to individual antimicrobials was significant between isolates from residents on farms that fed medicated swine rations compared to those that did not (p = 0.013). Cross-resistance among antimicrobials of same class and multidrug-resistance were observed. Logistic regression models revealed the following risk factors positively associated with antimicrobial resistance: use of antimicrobials in pigs on farms; number of hours per week that farmers spent in their pig barns; handling of sick pigs; and intake of antimicrobials by farm residents. This study indicates that occupational exposure of farmers to resistant bacteria and use of antimicrobials in pig farming may constitute a source of resistance in humans, although the human health impacts of such resistance is unknown. The consumption of antimicrobials by farmers appeared to constitute a significant risk for resistance development. Fecal E. coli from farm residents may act as a reservoir of resistance genes for animal and/or human pathogens.