Prudent Use Of Antimicrobials Research Articles

P21 | Prudent use of antimicrobials in cats at the veterinary teaching hospital of the university of Pisa, Italy

Journal of Veterinary Pharmacology and TherapeuticsVolume 46, Issue S1 p. 95-96 POSTER PRESENTATIONS P21 | Prudent use of antimicrobials in cats at the veterinary teaching hospital of the university of Pisa, Italy First published: 11 June 2023 https://doi.org/10.1111/jvp.13300Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume46, IssueS1Special Issue: 15th International Congress of the European Association for Veterinary Pharmacology and Toxicology held Bruges, Belgium, July 2–5, 2023June 2023Pages 95-96 RelatedInformation

Antimicrobial consumption in food-producing animals in Thailand between 2017 and 2019: The analysis of national importation and production data.

Antimicrobial resistance (AMR) threatens health security and the economy worldwide. AMR bacteria can spread across humans, animals, food webs and the environment. Excessive use of antimicrobials in food-producing animals has been recognised as one of the main drivers of the emergence of resistant bacteria. This study aims to quantify and identify patterns of antimicrobial consumption in food-producing animals in Thailand in a three-year period (2017-2019). Milligrams of active ingredient from total volume of imported and locally manufactured products minus exports were obtained from Thai FDA. Annual population production of food-producing animals in 2017, 2018 and 2019 was compiled and validated through cooperation between the Department of Livestock Development (DLD), Department of Fisheries (DOF). The total amount of antimicrobial consumption for food-producing animals decreased 49.0% over the three-year period from 658.7 mg/PCUThailand in 2017 to 336.3 mg/PCUThailand in 2019. In 2017, the most common antimicrobials used was macrolides which was replaced by aminopenicillins and pleuromutilins in 2019, while tetracyclines was consistently common over the three-year period. Consumption of the WHO Critically Important Antimicrobials (CIA) group declined significantly over this period, from 259.0 in 2017 to 193.2 mg/PCUThailand in 2019 (a 25.4% reduction). Findings from this study were in line with national policies which curtails prudent use of antimicrobials in food-producing animals. The government should maintain the decreasing trend of consumption, in particular of the CIA category. Improving information systems which captures consumption by specific species contributes to precision of interventions to minimise prudent use in each species.

Antimicrobial Susceptibility Profile of Pathogenic and Commensal Bacteria Recovered from Cattle and Goat Farms

The use of antibiotics in food animals results to antimicrobial resistant bacteria that complicates the ability to treat infections. The purpose of this study was to investigate the prevalence of pathogenic and commensal bacteria in soil, water, manure, and milk from cattle and goat farms. A total of 285 environmental and 81 milk samples were analyzed for Enterobacteriaceae by using biochemical and PCR techniques. Susceptibility to antibiotics was determined by the Kirby-Bauer disk diffusion technique. A total of 15 different Enterobacteriaceae species were identified from goat and cattle farms. Manure had significantly higher (p < 0.05) Enterobacteriaceae (52.0%) than soil (37.2%), trough water (5.4%), and runoff water (5.4%). There was a significant difference (p < 0.05) in Enterobacteriaceae in goat milk (53.9%) and cow milk (46.2%). Enterobacteriaceae from environment showed 100% resistance to novobiocin, erythromycin, and vancomycin E. coli O157:H7, Salmonella spp., Enterococcus spp., and Listeria monocytogenes displayed three, five, six, and ten. AMR patterns, respectively. NOV-TET-ERY-VAN was the most common phenotype observed in all isolates. Our study suggest that cattle and goat farms are reservoirs of multidrug-resistant bacteria. Food animal producers should be informed on the prudent use of antimicrobials, good agricultural practices, and biosecurity measures.

Biofilm expression and antimicrobial resistance patterns of Streptococcus uberis isolated from milk samples of dairy cows in South Africa.

The research described in this Research Communication addresses the hypothesis that intramammary infections with Streptococcus uberis (S. uberis) are associated with biofilm formation, which limits antibiotic efficacy. This retrospective study investigated biofilm expression and antimicrobial resistance (AMR) patterns of 172 S. uberis infections. Isolates were recovered from milk samples of subclinical, clinical, and intramammary infection cases on 30 commercial dairy herds. We determined the presence and intensity of biofilm expression of S. uberis isolates in vitro in three somatic cell count categories to recognise their AMR patterns. An automated minimum inhibitory concentration system with a commercially available panel of 23 antimicrobial agents evaluated AMR, while biofilm determination was conducted using a microplate method. The study established that all the S. uberis isolates assessed expressed biofilm with the following varying degrees of intensities: 30 (17.8%) strong, 59 (34.9%) medium and 80 (47.3%) weak biofilms. The newly registered UBAC mastitis vaccine containing biofilm adhesion components may, therefore, be a viable option for proactive mastitis management under field conditions. No differences were identified between biofilm intensity and the three somatic cell count groups. Most S. uberis isolates indicated a high-level sensitivity to the antimicrobial agents tested. Resistances were present in 8.7, 8.1 and 7.0% cases to rifampin, minocycline and tetracycline, respectively. Multidrug resistance was observed in 6.4%, emphasising AMR to antibiotics used in human medicine only. The low overall resistance suggests that farmers adhere to the prudent use of antimicrobials in the dairy industry.

Evaluation of the antimicrobial prescribing pattern and the stewardship programs among COVID-19 hospitals in the capital city of Kurdistan-Northern Iraq: A multicenter point prevalence study

Antimicrobial resistance (AMR) is a significant threat to healthcare system as making infections difficult to be cured and enhances disease transmission and death. Thus, prudent antimicrobial use is crucial to combat AMR, particularly in Erbil City/Northern Iraq because of the high rate of multidrug-resistance microorganisms. There is limited data on the extent and quality of antimicrobial use in Kurdistan, including COVID-19 hospitals. This study aimed to assess the prevalence and quality indicators of antimicrobial use, the status of antimicrobial stewardship program (ASP), and hospital capacity infrastructures. From September 30th 2021 to February 8th 2022, all COVID-19 hospitals in Erbil/Northern Iraq were surveyed using the Global point prevalence survey methodology. Prevalence of antimicrobial use was at the top (100%, n = 71/71), and carbapenem was the most used antimicrobial class (44.0%, n = 55/125). The majority of the prescribed antimicrobials were in WHO Watch class (88.4%, n = 76/86), high use of parenteral therapy (99.2%, n = 124/125), low targeted therapy (2.4%, n = 3/125) and neither stop/review dates documented, nor local guidelines were available. ASP was not implemented while most of the hospitals had a priority for the medium or long term to implement ASP (66.7%, n = 2/3) out of 11 hospital capacity infrastructures, only four of them were present adequately. The findings demonstrated a high and sub-optimal quality of antimicrobial prescriptions, lack of ASP, and inadequate hospital capacity infrastructures. Quick action is necessary to establish ASP to combat antimicrobial resistance, and the critical target areas include development of the local guidelines and documenting stop/review date.

A framework for evaluation of on-farm mastitis diagnostics in Australia.

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.

Antimicrobial resistance among canine enterococci in the northeastern United States, 2007-2020.

Antimicrobial resistance (AMR) is a growing and complex One Health concern worldwide, threatening the practice of human and veterinary medicine. Although dogs are a potential reservoir of multidrug-resistant bacteria, there are very few surveillance studies on AMR from the canine population in the United States. Here, we assessed the antimicrobial susceptibility patterns, identified temporal resistance and minimum inhibitory concentration trends, and described associations between resistance phenotypes among canine clinical enterococci in the northeastern United States. Through a large-scale retrospective study design, we collected species identification, minimum inhibitory concentration, and clinical data from 3,659 canine enterococci isolated at the Cornell University Animal Health Diagnostic Center between 2007 and 2020. We used the Mann-Kendall test, Sen's slope, multivariable logistic regression, and survival analysis models to detect the presence of a significant trend in resistance over the study period. Enterococcus faecalis was the most prevalent species (67.1% of isolates), followed by Enterococcus faecium (20.4%). We found high levels of AMR among enterococci to almost all the tested antimicrobials, particularly E. faecium. The lowest percentage of resistance was to vancomycin and chloramphenicol. Multidrug resistance was common (80% of E. faecium and 33% of E. faecalis) and 31 isolates were extensively drug resistant. Multidrug resistance among E. faecium increased over time, but not in E. faecalis. Resistance to penicillins, enrofloxacin, and rifampin increased during the study period, but resistance to tetracyclines is on a downward trajectory compared to AMR data from the last decade. Emerging vancomycin-resistant E. faecalis (0.3%) and E. faecium (0.8%) infections in the canine population are of great concern to both human and animal health. One E. faecium isolate with acquired vancomycin resistance was identified in 2017 and four vancomycin-resistant enterococci isolates were identified in 2020. There is a crucial need to make rational prescribing decisions on the prudent use of antimicrobials and improve the quality of care for patients, especially when empirical antimicrobial treatment for enterococcal infection is common.

Setting epidemiological cut-off values for Vibrio harveyi relevant to MIC data generated by a standardised microdilution method.

The lack of internationally harmonised criteria for interpreting the data generated by standardised susceptibility testing methods presents a serious obstacle for the development of prudent use of antimicrobials in aquaculture. The data required to set epidemiological cut-off values for minimum inhibitory concentrations for antibiotic agents against Vibrio harveyi was determined using a standard microdilution method that specified the use of cation-adjusted Mueller Hinton broth and incubation at 28°C for 24 to 28 h. In total, 120 observations were made in 4 independent laboratories from 109 unique isolates. The aggregated data from these laboratories were analysed by the normalised resistance method and by ECOFFinder to calculate epidemiological cut-off values. The data for chloramphenicol, meropenem and sulfamethoxazole were not considered as suitable for analysis. The data for ampicillin indicated that this species is innately resistant to this agent. No acceptable ranges for quality control strains have been set for ceftazidime and, therefore, only provisional cut-off values could be generated for this agent. The epidemiological cut-off values were, however, calculated for the other 6 agents. These values were ≤0.5 µg ml-1 for enrofloxacin, ≤1 µg ml-1 for florfenicol, oxolinic acid and oxytetracycline, ≤4 µg ml-1 for gentamicin and ≤0.5/9.5 µg ml-1 for trimethoprim/sulfamethoxazole. Evidence is presented demonstrating that the data for these 6 antimicrobial agents was of sufficient quantity and quality that they could be used by the relevant authorities to set internationally harmonised, consensus epidemiological cut-off values for V. harveyi.

Antibiotic-resistant threads of Aeromonas hydrophila as a major pathogen in Indonesia freshwater aquaculture

Aeromonas hydrophila is a zoonotic, important primary fish pathogen in many economic fish species. Aeromonas acquires and exchanges antimicrobial resistance genes (ARG) and has been widely studied as a potential reservoir of ARGs. This research aims to observe the impact of antibiotics used through the role of Aeromonas hydrophila as a pathogenic bacteria in aquaculture. The tested antibiotics are based on the Minister of Marine Affairs and Fisheries No. 1/2019 Decree, namely tetracycline, oxytetracycline, and enrofloxacin, which the Indonesian government allows to be used in aquaculture. Random sampling was conducted using four to five fishes per farm in West Java, namely Bogor (17 farms) and Sukabumi (10 farms), Central Java at Banyumas (38 farms), and Magelang (25 farms). The test method used is CLSI-2020, an Antimicrobial Sensitivity Test disk diffusion with standard bacteria ATCC Escherichia coli 25922. The results show that A. hydrophila is resistant to tetracycline by 15,06% and oxytetracycline by 54,54%. However, A. hydrophila is sensitive to enrofloxacin by 84%. The aquatic environment acts as a reservoir for antibiotic-resistant A. hydrophila and emphasizes the importance of prudent antimicrobial use and timely AMR surveillance in aquaculture.

Preserving our Defences – Prudent and Appropriate Use of Antimicrobials

Preserving our Defences – Prudent and Appropriate Use of Antimicrobials

Antimicrobial resistance: The next probable pandemic

Even as the world continues to grieve for those lost to the SARS-CoV-2 pandemic, another pandemic is brewing that has the potential to kill hundreds of millions of people in a century or less. In the far future, patients’ lives are being cut short in hospital wards by the stealthy but widespread epidemic of antimicrobial resistance. Unfortunately, the global health community is now confronting the silently growing pandemic that could threaten some of the most significant advancements in contemporary medicine. Considering that current medical professionals will eventually pass the torch to their students, who will hopefully lead to further improvements in antimicrobial resistance and antibiotic usage, medical students have the opportunity to contribute to a long-term solution to this problem. Future medical professionals, then, need to be better equipped to make prudent and economical use of antimicrobials.

Genetic diversity and risk factor analysis of drug-resistant Escherichia coli recovered from broiler chicken farms

A total of 38 Escherichia coli isolates were recovered from 120 samples collected from various sources of broiler chicken farms (n = 10 each) in Andhra Pradesh and Telangana states. Though the recovered E. coli isolates were found variably resistant to the tested antibiotics, all the tested isolates were susceptible to meropenem. Alarming multi-drug resistance (MDR) was observed (34/38) among the recovered isolates, wherein antibiotic-resistant genes (blaTEM, blaSHV, and tetA) were detected, except for blaCTX-M-9. The heatmap with cluster analysis exhibited that majority of the E. coli isolates recovered from different sources and regions clustered together based on their phenotypic resistance suggesting co-sharing of resistance. However, the pulsed-field gel electrophoresis (PFGE) typing revealed an extremely diverse genotypic profile. Further, a significant statistical association was not observed between hypothesized risk factors and recovered MDR- E. coli isolates from various sources, although a significant statistical association between antibiotic resistance with large flock size, poor biosecurity practices, poor workers’ hygiene, and poor disinfection practices was noticed. Since the study highlighted an alarming level of drug resistance among the recovered E. coli isolates, further in-depth research in similar veins is required to ensure the prudent use of antimicrobials in the poultry sector and the implementation of an antimicrobial surveillance system.

Bayesian latent class models to determine diagnostic sensitivities and specificities of two point of care rapid tests (Selma plus, Dipslide) for the detection of Streptococcus uberis associated with mastitis in dairy cows.

Development and validations of accurate mastitis diagnostics are crucial to make timely and evidence-based decisions on mastitis therapy in order to reduce its impact on productivity, animal welfare and practicing the prudent use of antimicrobials on dairy farms. The objectives of this study were to assess the agreement between test results from reference laboratory and two point of care tests (Selma plus, Dipslide) and to estimate the test accuracies with Bayesian latent class models (BLCMs). In total of 509 single quarter milk samples from cows with mastitis were included in the study. Among all analyzed mastitis pathogens, Streptococcus spp. was detected in up to one third of all analyzed samples and for Selma all Streptococcus samples were considered as Streptococcus uberis. The agreement (κ) when comparing two tests varied greatly depending on the bacteria, ranging from no agreement to good agreement (κ = negative to 0.86) depending on the prevalence of identified pathogens. Based on BLCMs to assess diagnostic test accuracies for the pathogen Streptococcus uberis, posterior sensitivities of 76, 71, and 64% for Selma plus, Dipslide and laboratory standard culture and specificities of 93%, 98% for Selma and Dipslide, respectively, were obtained. The two point of care rapid culture systems Dipslide and Selma plus plate can provide important preliminary pathogen identification for targeted mastitis therapy, especially when general information about growth and a rough classification of the bacteria into groups have an impact on treatment strategy. The two evaluated rapid culture systems, Dipslide and Selma plus plate, show good test accuracies for Streptococcus uberis at least at genus level. Therefore, using these tests may contribute to prudent use of antibiotics.

A participatory approach for building ex ante impact pathways towards a prudent use of antimicrobials in pig and poultry sectors in France

A participatory approach for building ex ante impact pathways towards a prudent use of antimicrobials in pig and poultry sectors in France

A participatory approach for building ex ante impact pathways towards a prudent use of antimicrobials in pig and poultry sectors in France.

Antimicrobial resistance (AMR) is a global public health threat responsible for 700,000 deaths per year worldwide. There is scientific evidence of the causal relationship between antimicrobial use (AMU) along the food chain and AMR. Improving AMU in livestock is therefore a key component in the fight against AMR. To improve AMU in livestock, there is no one-size-fits-all solution and strategies must be context-adapted and socially acceptable for actors in order to increase AMU sustainability. AMU decision-making is based on an interdependent set of economic, behavioral, ethical, and cultural factors that need to be assessed to advise on the potential impacts of measures. We hypothesized that a participatory strategic planning approach may increase the plausibility and the efficacy of the strategies formulated by facilitating the dialogue between actors of diverse backgrounds, stimulating innovative thinking and constant considerations of contextual factors, actors and impacts. We adapted and applied the ImpresS ex ante approach (IMPact in reSearch in the South, https://impress-impact-recherche.cirad.fr/) within a Living Lab engaging actors from the French pig and poultry sectors in co-creation of innovative strategies towards improved AMU. We conducted semi-structured interviews and participatory workshops between April 2021 and March 2022. The results describe 1) an initial diagnosis of the current AMU situation in the pig and poultry sectors in France; 2) a common vision of the future to which participants would like to contribute through the intervention; 3) an identification of the current problems opposed to this vision of the future; 4) a defined scope of the intervention; 5) a typology of actors protagonist or impacted by those issues and 6) outcome maps to solve a priority problem related to indicators and monitoring. This study provides recommendations for decision-makers on plausible and innovative strategies to sustainably improve AMU in pig and poultry sectors in France and evidence of the benefits of participatory strategic planning approaches.

Knowledge, Attitude, and Behavior about Antimicrobial Use and Resistance among Medical, Nursing and Pharmacy Students in Jordan: A Cross Sectional Study.

The present study aimed to survey medical, nursing and pharmacy students' knowledge, attitude and practice regarding antimicrobial use and resistance. Additionally, the study assessed the teaching and assessment activities received regarding antibiotic use. A cross sectional online survey was distributed to undergraduate students currently in clinical studies in their degree program. A total of 716 medicine, nursing and pharmacy undergraduate students were included. Respondents scored more than 76% on knowledge on effective use, unnecessary use and associated side effects of antibiotics, and 65.2% regarding knowledge on the spread of antibiotic resistance. Some participants (21.0%) agreed or strongly agreed that there has been good promotion of prudent antimicrobial use. Students were aware (13.1%), unaware (29.1%), or unsure (57.8%) that there is a national action plan relating to antimicrobial resistance. A total of 62.8% of the respondents strongly agreed or agreed that they have a key role in helping control antibiotic resistance. Participants reported that they require more information about resistance to antibiotics (53.9%), medical conditions for which antibiotics are used (51.7%) and how to use antibiotics (51.0%). Discussion of clinical cases and vignettes and small group teaching were reported as very useful or useful teaching strategies (79.9% and 74.2%, respectively). The findings from this study determined the current situation in relation to education on prudent antimicrobial use for undergraduates and highlighted areas for informing better curriculum design.

Economic evaluation of antimicrobial use practices in animal agriculture: a case of poultry farming.

The growing evidence of the contribution of antimicrobial use (AMU) in animal agriculture to the public health threat of antimicrobial resistance has highlighted to policymakers the importance of the need for prudent AMU in animal production. Livestock farming is an economic process, where farmers are using inputs such as antimicrobials to minimize their losses. Using a large and unique dataset combining time-series data on economic performance and health records in conventional broiler production in France, we identify how improved healthcare management and disease prevention impact economic performance, AMU reduction and health outcomes. We analyse the main characteristics of the economic performance of farms measured by the profit per m2, by performing advanced regression models investigating the relative importance of medication and veterinary procedures. In our study, 50% of the treatments (expressed as number of new treatments) are attributable to only 30% of all flocks. There is an inverted U-shaped relationship between AMU and economic performance. This finding implies that the marginal profit of antimicrobials is decreasing, meaning that using antimicrobials is only profitable up to a certain threshold. Results also show that the profit increases as the number of preventive treatments increase. Our findings suggest that policies encouraging farmers to work upstream from the occurrence of disease have the potential to perform better than regulations, as they would maintain a profitable activity while diminishing AMU. Encouraging adequate infection control practices by subsidizing or providing other incentives would benefit farmers and society.

Prevalence of Antimicrobial Prescribing in Long-Term Care Facilities in a Local Health Authority of Northern Italy.

Background: Almost half of antimicrobial prescriptions in long-term care facilities (LTCFs) is inappropriate. This broad use might represent a strong contributor to antimicrobial resistance in these facilities. This study aimed to assess antibiotic use patterns and potential associated factors with a survey of LTCFs in the local health authority (LHA) of Novara. Methods: A cross-sectional study was conducted in 25 LTCFs in the LHA of Novara following the healthcare-associated infection in LCTFs (HALT) protocol. Information on residents and facilities was assessed. Antibiotic usage and potential determinants were also estimated. Results: In total, 1137 patients were screened for antibiotic usage. Mean age was 84.58 years (SD 9.77), and the majority were female (76.52%). Twenty-six were antibiotic users (prevalence rate 2.29%, 95%CI 1.50–3.33). Antimicrobials were mainly prescribed orally (84.62%). Potential risk factors for antibiotic prescription were catheter use (central and peripheral venous, p-values 0.0475 and 0.0034, respectively, and urinary, p-value 0.0008), immobilization (p-value < 0.0001), and sex (p-value 0.0486). Conclusions: This study identified a low prevalence of antimicrobic consumption in LTCFs. Further surveillance studies are warranted to identify trends and changes in pathogen incidence and antimicrobial resistance and to inform public health authorities on the necessity of prudent use of antimicrobials in LCTFs.

Phenotypic and Genotypic Analysis of Antimicrobial Resistance in Escherichia coli Recovered from Feedlot Beef Cattle in Australia.

Simple SummaryAntimicrobial resistance (AMR) is a major concern for animal and human health. The use of antimicrobials is the main factor contributing to the development of AMR in food-producing animals but is unlikely to be the only factor. It is important to determine if antimicrobial use in a feedlot setting contributes to the overall resistance burden and what proportion of animals may already harbour resistant bacteria at feedlot entry. This project aimed to assess the level of AMR in E. coli isolated from beef cattle in South Australia at two time points, the entry and exit (at slaughter) from the beef feedlot. AMR frequency in E. coli isolated from entry compared to exit increased for tetracycline (0 to 17.8%), ampicillin (0.7 to 5.4%), streptomycin (0.7 to 4.7%), and sulfisoxazole (0 to 3.9%). Therefore, the regular inspection of these bacteria and their resistance determinants in food animals would be crucial to tracking changes in AMR and applying control mechanisms.This study investigated the antimicrobial resistance (AMR) profile of fecal Escherichia coli isolates from beef cattle (n = 150) at entry and exit from an Australian feedlot. Sample plating on MacConkey agar and Brilliance ESBL agar differentiated generic from extended-spectrum β-lactamase (ESBL)-producing E. coli, respectively. Resistance profiles were determined by minimum inhibitory concentration (MIC) testing and further analyzed by whole-genome sequencing (WGS). At entry, the prevalence of antimicrobial resistance to amoxicillin/clavulanic acid, ampicillin, streptomycin, and trimethoprim/sulfamethoxazole was very low (0.7%, each). At the exit, the resistance prevalence was moderate to tetracycline (17.8%) and low to ampicillin (5.4%), streptomycin (4.7%), and sulfisoxazole (3.9%). The most common AMR genes observed in phenotypically resistant isolates were tet(B) (43.2%), aph(3″)-Ib and aph(6)-Id (32.4%), blaTEM-1B, and sul2 (24.3%, each), which are responsible for resistance to tetracyclines, aminoglycosides, β-lactams, and sulfonamides, respectively. The ESBL-producing E. coli were recovered from one sample (0.7%) obtained at entry and six samples (4.0%) at the exit. The ESBL-producing E. coli harbored blaTEM (29.7%), blaCTX m (13.5%), and blaCMY (5.4%). The resistance phenotypes were highly correlated with resistance genotypes (r ≥ 0.85: p < 0.05). This study demonstrated that E. coli isolated from feedlot beef cattle can harbour AMR genes, but the low incidence of medically important resistance reflected the prudent antimicrobial use in the Australian industry.

Vaccination with an Escherichia coli F4/F18 Vaccine Improves Piglet Performance Combined with a Reduction in Antimicrobial Use and Secondary Infections Due to Streptococcus suis.

Simple SummaryPost-weaning diarrhea (PWD) due to Escherichia coli (E. coli) remains a major cause of economic losses for the pig industry. Therapy to combat PWD typically consists of antibiotic treatment or supplementation of zinc oxide to the feed. The emergence of antimicrobial resistance and new EU regulations prompt the need for alternative control strategies, such as immunization. The aim of the field study was to evaluate the effect of an oral live non-pathogenic E. coli vaccine on piglet performance, health, and antimicrobial use. We compared 10 batches receiving a standard antimicrobial control treatment to 10 batches vaccinated with the oral E. coli vaccine. The vaccine-treated groups demonstrated a significant improvement in performance, mortality weight, and antimicrobial use. In addition, secondary infections due to Streptococcus suis in the second part of nursery were reduced, as indicated by the reduction in amoxicillin use. In conclusion, the present study demonstrates the efficacy of an oral live non-pathogenic E. coli vaccine for the active immunization of piglets against PWD under field conditions. Therefore, vaccination against PWD may be considered a valuable alternative for strengthening piglet performance while meeting the new EU requirements concerning the prudent use of antimicrobials in intensive pig production.Post-weaning diarrhea (PWD) due to Escherichia coli (E. coli) remains a major cause of economic losses for the pig industry. Therapy to combat PWD typically consists of antibiotic treatment or supplementation of zinc oxide to the feed. The emergence of antimicrobial resistance to E. coli and new EU regulations prompt the need for alternative control strategies, such as immunization. The aim of the field study was to evaluate the effect of an oral live non-pathogenic E. coli vaccine on piglet performance, health, and antimicrobial use. We evaluated vaccination with an oral live non-pathogenic E. coli F4/F18 under field conditions in 10 consecutive batches against a standard antimicrobial treatment in 10 historical control batches. The vaccine-treated groups demonstrated a significant improvement in feed conversion rate, mortality weight, and antimicrobial use. From a general health perspective, secondary infections due to Streptococcus suis (S. suis) in the second part of nursery were markedly reduced, as indicated by the reduction in amoxicillin use. In conclusion, the present study demonstrates the efficacy of an oral live non-pathogenic E. coli vaccine for active immunization of piglets against PWD under field conditions. The vaccine-treated groups showed an improvement in several economically important performance parameters while reducing the overall antimicrobial use and infection pressure due to S. suis. Therefore, vaccination against PWD may be considered a valuable alternative for consolidating piglet performance while meeting the new EU requirements concerning the prudent use of antimicrobials in intensive pig production.