Prudent Use Of Antimicrobials Research Articles

Multiple impacts of the COVID-19 pandemic and antimicrobial stewardship on antimicrobial resistance in nosocomial infections: an interrupted time series analysis.

The emergency response to the COVID-19 pandemic may disrupt hospital management activities of antimicrobial resistance (AMR). This study aimed to determine the changing AMR trend over the period in China when stringent COVID-19 response measures were implemented. This retrospective study was conducted in a designated hospital for COVID-19 patients in Guangzhou, China from April 2018 to September 2021. The prevalence of 13 antimicrobial-resistant bacteria was compared before and after the COVID-19 responses through Chi-square tests. Interrupted time series (ITS) models on the weekly prevalence of AMR were established to determine the changing trend. Controlled ITS models were performed to compare the differences between subgroups. A total of 10,134 isolates over 1,265 days were collected. And antimicrobial-resistant strains presented in 38.6% of the testing isolates. The weekly AMR prevalence decreased by 0.29 percentage point (95% CI [0.05-0.80]) after antimicrobial stewardship (AMS) policy, despite an increase in the prevalence of penicillin-resistant Streptococcus pneumoniae (from 0/43 to 15/43, p < 0.001), carbapenem-resistant Escherichia coli (from 20/1254 to 41/1184, p = 0.005), and carbapenem-resistant Klebsiella pneumoniae (from 93/889 to 114/828, p = 0.042). And the changing trend did not vary by gender (male vs. female), age (<65 vs. ≥65 years), service setting (outpatient vs. inpatient), care unit (ICU vs. non-ICU), the primary site of infection (Lung vs. others), and Gram type of bacteria (positive vs. negative). The response to COVID-19 did not lead to an increase in overall AMR; however, it appears that management strategy on the prudent use of antimicrobials likely contributed to a sizable long-term drop. The frequency of several multidrug-resistant bacteria continues to increase after the COVID-19 epidemic. It is crucial to continue to monitor AMR when COVID-19 cases have surged in China after the relaxation of restriction measures.

Antimicrobials Use by Smallholder Dairy Farmers in Peri-Urban Area of Nakuru Kenya: Knowledge, Attitudes and Practices

In dairy intensification, mastitis infections become prevalent and induce frequent Antimicrobial Use (AMU), sometimes inappropriately. This poses public health risks because of growing Antimicrobial Resistance (AMR), which calls for stewardship programs informed by Knowledge, Attitude and Practices (KAPs) about AMU and AMR to halt or reverse the worrying trend. Data was obtained in cross sectional survey conducted in four peri-urban wards around Nakuru city in Kenya. Randomly selected sample farmers (n=124) with free-grazing, semi-zero-grazing or zero-grazing dairy management, representing increasing dairy intensification levels provided data on the KAPs. Chi-square test statistics was fitted to establish associations between KAPs and dairy intensification levels. Among the sample farmers, six in ten (58.8 percent) had intensified dairy production, at least six in ten were marketing milk through informal outlets and were using antimicrobial drugs. Compliance with the withdrawal period was high and increased (p&amp;lt;0.05) with increasing intensification from free-grazing to zero-grazing. Within antibiotic withdrawal period, at least seven in ten farmers did not sell milk, fewer than four in ten consumed their milk at home and fewer than three in ten fed the milk to calves. Though independent of dairy intensification level (p&amp;gt;0.05), using antimicrobials for mastitis treatment increased while sourcing information on antimicrobial use from extension and veterinary officers decreased, with increasing intensification level. Farmers with some training on prudent antimicrobial use and with positive attitudes that milk from antimicrobial treated cows is unsafe, antimicrobial resistant pathogens and residues can be passed from milk to humans, mastitis can be treated without antimicrobial drugs, and antimicrobial residues can end up accumulating in the soils increased (p&amp;gt;0.05) with increasing dairy intensification levels. These results show that regarding AMU and AMR, farmers become more knowledgeable, with positive attitudes and good practices as they intensify their dairy management. The implication is that intensification of dairy management motivates farmers to gain more knowledge, acquire positive attitudes and apply good practices towards responsible prudent use of antimicrobials in livestock. Therefore, strengthening stewardship with targeted training and sensitization can foster prudent and responsible antimicrobial use.

Development of an animal health testing tool to reduce antimicrobial use on farms: perceptions, implications, and needs of Irish dairy farmers and farm veterinarians

BackgroundThe threat of antimicrobial resistance is triggering the need for behavioural change towards antimicrobial use on Irish farms. Newly introduced veterinary medicine regulations are mandating the restricted and more prudent use of antimicrobials in the animal health sector. The need to reduce antimicrobials has placed a greater emphasis on the importance of animal health testing, however, issues with current testing practices are affecting diagnosis and subsequent drug usage. There is potential for digital technologies to address these issues and reduce antimicrobial use on farms, however, for these tools to be successful, they would need to be developed in collaboration with future end users.ResultsUsing qualitative approaches (focus groups), this study engages with dairy farmers and farm veterinary practitioners to detail current challenges with animal health diagnosis and to explore the initial development of a rapid, on-farm animal health testing tool to address these challenges. Issues with timing and testing, the role of knowledge and experience, and veterinarian availability all affect the ability of farmers and veterinarians to diagnose animal health issues on farm. These issues are having negative implications including the increased and unnecessary use of antimicrobials. An on-farm testing tool would help mitigate these effects by allowing veterinarians to achieve rapid diagnosis, facilitating the timely and targeted treatment of animal illnesses, helping to reduce overall antimicrobial use on farms. However, engagement with end users has highlighted that if a tool like this is not developed correctly, it could have unintended negative consequences such as misdiagnosis, increased antimicrobial use, challenges to farmer-veterinarian relationships, and data misuse. This study outlines initial end user needs and requirements for a testing tool but suggests that in order to successfully design and develop this tool, co-design approaches such as Design Thinking should be applied; to mitigate future negative impacts, and to ensure a testing tool like this is designed specifically to address Irish dairy farmers and farm veterinarians’ values and needs, ensuring responsible and successful uptake and use.ConclusionsDigital tools can be effective in reducing antimicrobial use on farms, however, to be successful, these tools should be designed in a user centred way.

One Health Landscape of Antimicrobial Resistance in Bacteria Isolated from Virginia between 2007-2021.

The emergence of antimicrobial-resistant (AMR) bacteria has become a critical global One Health issue, mainly attributed to the extensive use of antimicrobial agents in human and agricultural settings. Regional and local AMR surveillance data is essential for implementing awareness and mitigation strategies. This article assesses AMR frequency in 1604 bacterial isolates consisting of Escherichia coli (E. coli) and Salmonella spp. isolated from diverse sources in Virginia, including farm animals, wildlife, environment, and food samples from 2007 to 2021. The results are based on the Kirby-Bauer disc diffusion assessment method of susceptibility to select antimicrobial agents, spanning nine distinct categories approved by the US Food and Drug Administration for clinical use. Streptomycin (STR) and tetracycline (TCY) exhibited the highest frequency of resistance in E. coli (39.1%) and Salmonella (25.2%), respectively. Multidrug resistance (MDR) was evident in 6.6% of E. coli and 10.9% of Salmonella isolates. Notably, 51% of E. coli and 36% of Salmonella isolates demonstrated resistance to more than one antimicrobial. None of the tested antimicrobials guaranteed effectiveness against the bacteria isolated from the surveyed sources and regions. The study found heightened MDR and distinct AMR patterns in bacteria isolated from food products compared to other sampled sources. These findings are vital for comprehending the current AMR landscape, prompting the development of strategies to mitigate the emergence of AMR bacteria, and advocating prudent antimicrobial use from a One Health perspective.

Attitudes of South Korean consumers toward the prudent use of antimicrobials in livestock animals

Antimicrobial resistance (AMR) in livestock is a complicated and multi-sectoral risk that threatens public health in the interactions between humans, animals, and environment. Through their increased awareness of AMR issues, consumers can make a significant impact on regulations and strategies to reduce or eliminate the use of antimicrobials use. This study aims to provide evidence-based data for promoting the prudent use of antimicrobials (PUA) in the livestock industry to reduce the risk of AMR and increase animal welfare by identifying consumers' intentions to support PUA practices in livestock farming. An online survey was conducted on 1000 respondents in South Korea to examine their intention to pay more for PUA practices in livestock farming at state and individual levels against their pro-animal attitude, risk perception of antimicrobial overuse, trust in antimicrobial overuse control, and perceived value of PUA practices. The survey data was analyzed using multiple linear regression to identify the determinants of Korean consumers' support for PUA practices. Approximately 86.3% of the respondents supported government-level spending for PUA in livestock farming, and the same portion of respondents intended to pay more for livestock products that complied with the PUA principle. The four attitudinal variables—pro-animal attitude, consumers' risk perception, trust in antimicrobial resistance control, and perceived value of PUA—positively affected both state- and individual-level support. Overall, our findings highlight the Korean consumers' demand for reducing the risk of AMR and their perceived universal value of PUA for humans and animals.

Survey of farm, parlour and milking management, parlour technologies, SCC control strategies and farmer demographics on Irish dairy farms

BackgroundThis cross-sectional study describes a survey designed to fill knowledge gaps regarding farm management practices, parlour management practices and implemented technologies, milking management practices, somatic cell count (SCC) control strategies, farmer demographics and attitudes around SCC management on a sample of Irish dairy farms.ResultsWe categorized 376 complete responses by herd size quartile and calving pattern. The average respondent herd was 131 cows with most (82.2%) operating a seasonal calving system. The median monthly bulk tank somatic cell count for seasonal calving systems was 137,000 cells/ml (range 20,000 – 1,269,000 cells/ml), 170,000 cells/ml for split-calving systems (range 46,000 – 644,000 cells/ml) and 186,000 cells/ml for ‘other’ herds (range 20,000 – 664,000 cells/ml). The most common parlour types were swing-over herringbones (59.1%) and herringbones with recording jars (22.2%). The average number of units across herringbone parlours was 15, 49 in rotary parlours and two boxes on automatic milking system (AMS) farms. The most common parlour technologies were in-parlour feeding systems (84.5%), automatic washers on the bulk tank (72.8%), automatic cluster removers (57.9%), and entrance or exit gates controlled from the parlour pit (52.2%). Veterinary professionals, farming colleagues and processor milk quality advisors were the most commonly utilised sources of advice for SCC management (by 76.9%, 50.0% and 39.2% of respondents respectively).ConclusionsIn this study, we successfully utilised a national survey to quantify farm management practices, parlour management practices and technology adoption levels, milking management practices, SCC control strategies and farmer demographics on 376 dairy farms in the Republic of Ireland. Rotary and AMS parlours had the most parlour technologies of any parlour type. Technology add-ons were generally less prevalent on farms with smaller herds. Despite finding areas for improvement with regard to frequency of liner changes, glove-wearing practices and engagement with bacteriology of milk samples, we also found evidence of high levels of documentation of mastitis treatments and high use of post-milking teat disinfection. We discovered that Irish dairy farmers are relatively content in their careers but face pressures regarding changes to the legislation around prudent antimicrobial use in their herds.

Resistome, Virulome, and Clonal Variation in Methicillin-Resistant Staphylococcus aureus (MRSA) in Healthy Swine Populations: A Cross-Sectional Study.

This cross-sectional study investigates the methicillin-resistant Staphylococcus aureus (MRSA): its prevalence, antimicrobial resistance, and molecular characteristics in healthy swine populations in central Portugal. A total of 213 samples were collected from pigs on twelve farms, and MRSA prevalence was assessed using selective agar plates and confirmed via molecular methods. Antimicrobial susceptibility testing and whole genome sequencing (WGS) were performed to characterize resistance profiles and genetic determinants. Among the 107 MRSA-positive samples (83.1% prevalence), fattening pigs and breeding sows exhibited notably high carriage rates. The genome of 20 isolates revealed the predominance of the ST398 clonal complex, with diverse spa types identified. Antimicrobial susceptibility testing demonstrated resistance to multiple antimicrobial agents, including penicillin, cefoxitin, and tetracycline. WGS analysis identified a diverse array of resistance genes, highlighting the genetic basis of antimicrobial resistance. Moreover, virulence gene profiling revealed the presence of genes associated with pathogenicity. These findings underscore the significant prevalence of MRSA in swine populations and emphasize the need for enhanced surveillance and control measures to mitigate zoonotic transmission risks. Implementation of prudent antimicrobial use practices and targeted intervention strategies is essential to reducing MRSA prevalence and safeguarding public health. Continued research efforts are warranted to elucidate transmission dynamics and virulence potential, ultimately ensuring food safety and public health protection.

Changing Patterns of Organisms Causing Neonatal Sepsis and Their Antimicrobial Sensitivity Profile in a Tertiary Center - A Prospective Study.

To identify the profile of organisms causing neonatal sepsis and their antibiotic susceptibility pattern in recent years. In this prospective study, authors included neonates with blood culture proven sepsis. Antibiotic resistance patterns that were identified were extended spectrum β-lactamase, AmpC β-lactamase and possible carbapenamase producer. Xpert CARBA-R test was performed to identify genes causing carbapenem resistance. There were 210 neonates with 216 episodes of blood culture proven sepsis. Klebsiella pneumoniae (n = 85) and Escherichia coli (n = 19) were the most common gram-negative organisms. Coagulase negative Staphylococcus (n = 11) and Staphylococcus aureus (n = 7) were the mostcommon gram positive organisms. There were 17 episodes of fungal sepsis with Candida albicans (n = 6) being the most common. Sixty-five out of 216 (30%) organisms were multidrug resistant. Among the Klebsiella isolates, 32/85 (37.6%) were possible carbapenamase producers. Xpert CARBA-R performed for 13 infants showed that all were positive for New Delhi metallo-β-lactamase. Among the 19 Escherichia coli, 10/19 (37.6%) were multidrug resistant and 1/19 (5.3%) was a possible carbapenamase producer. The authors found a significant increase in New Delhi metallo-β-lactamase positive Klebsiella pneumoniae causing neonatal sepsis in last three years. Regular monitoring of resistance patterns and prudent use of antimicrobials are imperative in regulating the shadow pandemic of multi-drug resistant neonatal sepsis.

Escherichia coli isolates from vegetable farms in Addis Ababa, Ethiopia: Antimicrobial susceptibility profile and associated resistance genetic markers.

The use of animal manure to fertilize soil is an emerging concern contributing to the transfer of antimicrobial-resistant pathogens to vegetables. Hence, assessing antimicrobial susceptibility profile of Escherichia coli in vegetable farms is essential to design appropriate interventions against antimicrobial resistance (AMR) in the food chain. This study assessed antimicrobial resistance profile and associated genetic markers among E. coli isolated from vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 1044 samples were collected using convenience sampling: soil (n = 271), manure (n = 375), and vegetables (n = 398) from 81 vegetable farms in Addis Ababa, Ethiopia. Antimicrobial susceptibility test was conducted for 100 E. coli isolates and antimicrobial resistance genes (ARGs) were tested by polymerase chain reaction (PCR). Of the 1044 collected samples, 25.3% were positive for E. coli, with significantly higher prevalence in the manure sample and samples collected from Akaki Kality sub-city (p < .05). The highest resistance rate was recorded for tetracycline (72%), followed by streptomycin (63%), and sulfamethoxazole +trimethoprim (56%). Multidrug resistance was detected in 61% of the E. coli isolates. The aac(3)-IV (76.9%), bla TEM (65.4%), aadA (60.3%), tet(A) (58.3%), and sulI (51.7%) were the commonly detected resistance genes. The current study showed a high burden of antimicrobial resistance among E. coli isolated from manure-amended vegetable farms, with potential of playing a significant role in the dissemination of antimicrobial resistance in the food chain. Efforts should be made to reduce the burden of resistant organisms and ARGs through prudent use of antimicrobials in livestock and application of appropriate composting techniques before using manure as fertilizer.

The Role of Medical Microbiologists in Advancing the Frontiers of Travel Medicine

The essential role of medical microbiologists in the field of travel medicine becomes apparent amidst the escalating challenges faced by our world. This article highlights their indispensable contributions to safeguarding global health during travel. Medical microbiologists play a pivotal part in defending against infectious threats encountered during travel, identifying and characterizing novel pathogens, developing rapid diagnostic tools, and spearheading outbreak investigations for early detection and containment. Their active involvement in vaccine development and surveillance is critical for ensuring the safety of travelers, and they address vaccine hesitancy through educational initiatives and advocacy. Moreover, they combat the growing issue of antimicrobial resistance, influencing travel health guidelines and promoting prudent antimicrobial use to minimize resistance risks. Collaboration is paramount in tackling global health threats, and medical microbiologists facilitate the exchange of information, reinforcing global surveillance networks to respond effectively to emerging infections. Their role in training the next generation of experts ensures a sustainable and knowledgeable workforce in travel medicine. As we navigate the continually evolving landscape of travel, the expertise of medical microbiologists becomes increasingly vital. Their dedication to advancing travel medicine through research, education, and collaborative efforts ensures that travel remains a positive force, promoting exploration while mitigating health risks. Recognizing and supporting their endeavors contribute to building a safer and healthier future for travelers and communities worldwide.

Effect of prudent use of antimicrobials in the early phase of infection in pigs on the performance and meat quality of fattening pigs

The presented study was a part of the ThermoEye project. The study examined the effect of prudent antibiotic treatment in response to illness on the fattening performance, slaughter traits, and meat quality of the pig fatteners. Pigs were divided into an experimental group – EXP and a control – CON. In both groups, the body temperature was monitored, and diseases were confirmed by a veterinarian. In the EXP group, metaphylaxis was used in each case of confirmed disease. The EXP fatteners had greater slaughter weight (by 4.7 kg) and meatiness (by 2.1 percentage points) compared to the CON pigs. The pH in pork was lower in EXP compared to CON pigs. The longissimus thoracis et lumborum of EXP pigs was characterised by a lower cooking loss (28.30 vs. 30.45%) and yellower colour compared to the CON group. Among the amino acids, only the content of histidine (by 5.2%; P < 0.01) and tyrosine (by 7.2%; P < 0.01) was significantly greater in the meat of the CON group compared to EXP, with no effect of sex noted. The content of SFA (by 14.6%; P < 0.05), UFA (by 15.6%; P < 0.05), MUFA (by 17.8%; P < 0.05), MCFA (by 14.1%; P < 0.05), and LCFA (by 15.6%; P < 0.05) was also greater in CON compared to EXP meat. In conclusion, automated monitoring of pig body temperature during the fattening period enables more precise, prudent treatment and effective animal health control while reducing costs due to disease losses and pharmacotherapy. It allows optimal production and affects meat quality.

Assessment of the Implementation of Pakistan's National Action Plan on Antimicrobial Resistance in the Agriculture and Food Sectors.

The agriculture and food (agrifood) sectors play key roles in the emergence, spread, and containment of antimicrobial resistance (AMR). Pakistan's first National Action Plan (NAP) on AMR was developed to guide One Health interventions to combat AMR through 2017-2022. To improve subsequent iterations, we assessed the implementation of Pakistan's NAP in the agrifood sectors (NAPag) in October 2022, using the Progressive Management Pathway on AMR tool developed by the Food and Agriculture Organization of the United Nations (FAO). The assessment tool addressed four crucial focus areas of the NAPag: governance, awareness, evidence, and practices. Each focus area contains multiple topics, which involve four sequential stages of activities to progressively achieve systematic management of AMR risk in the agrifood sectors. High-level representatives of the NAPag stakeholders provided information for the assessment through pre-event documentary review and workshop discussions. The assessment results showed that Pakistan's NAPag had an overall moderate coverage (59%) of the anticipated activities. Gaps were particularly notable in strengthening governance, good practices, and interventions in non-livestock sectors. Furthermore, only 12% of the evaluated activities were fully executed and documented, consistently remaining at the planning and piloting stages in the livestock sector across all the examined topics. Insufficient attention to non-livestock sectors, inadequate regulation and enforcement capacity, and resource constraints have hindered scalable and sustainable interventions under the current plan. This assessment provides valuable insights to strengthen the inclusiveness and contribution of the agrifood sectors in the next NAP iteration. In the short-to-medium term, strategic prioritization is necessary to optimize the use of limited resources and target the most critical gaps, such as improving awareness among key stakeholders and fortifying regulations for prudent antimicrobial use. In the long term, integration of AMR into the country's broader health, development, and agricultural transformation agendas will be needed to generate sustainable benefits.

Pneumococcal population genomics changes during the early time period of conjugate vaccine uptake in southern India.

Streptococcus pneumoniae is a major cause of invasive disease of young children in low- and middle-income countries. In southern India, pneumococcal conjugate vaccines (PCVs) that can prevent invasive pneumococcal disease began to be used more frequently after 2015. To characterize pneumococcal evolution during the early time period of PCV uptake in southern India, genomes were sequenced and selected characteristics were determined for 402 invasive isolates collected from children <5 years of age during routine surveillance from 1991 to 2020. Overall, the prevalence and diversity of vaccine type (VT) and non-vaccine type (NVT) isolates did not significantly change post-uptake of PCV. Individually, serotype 1 and global pneumococcal sequence cluster (GPSC or strain lineage) 2 significantly decreased, whereas serotypes 6B, 9V and 19A and GPSCs 1, 6, 10 and 23 significantly increased in proportion post-uptake of PCV. Resistance determinants to penicillin, erythromycin, co-trimoxazole, fluoroquinolones and tetracycline, and multidrug resistance significantly increased in proportion post-uptake of PCV and especially among VT isolates. Co-trimoxazole resistance determinants were common pre- and post-uptake of PCV (85 and 93 %, respectively) and experienced the highest rates of recombination in the genome. Accessory gene frequencies were seen to be changing by small amounts across the frequency spectrum specifically among VT isolates, with the largest changes linked to antimicrobial resistance determinants. In summary, these results indicate that as of 2020 this pneumococcal population was not yet approaching a PCV-induced equilibrium and they highlight changes related to antimicrobial resistance. Augmenting PCV coverage and prudent use of antimicrobials are needed to counter invasive pneumococcal disease in this region.

Laboratory evaluation of a rapid diagnostic test for dairy mastitis.

Rapid diagnostic tests that differentiate between Gram positive, Gram negative and the absence of aerobic bacteria in milk samples from dairy cows with clinical mastitis can support antimicrobial treatment decisions and contribute to a more prudent use of antimicrobials in the dairy industry. The objective of this study was to evaluate the test characteristics of the novel rapid BACT mastitis test in discriminating causes of clinical mastitis under laboratory conditions. Test outcomes of 155 milk samples from clinical mastitis cases were incubated for 14-16 h in the BACT test and compared to results of bacteriological culture. The accuracy for detection of bacterial growth and Gram positive growth was 91 and 89%, respectively. The BACT test could provide an accurate and relatively fast decision tool for farmers to aid in antimicrobial treatment decisions in cases of clinical mastitis.

Alternative approaches for treating canine otitis externa caused by Malassezia pachydermatis

Malassezia pachydermatis is a fungal pathogen that often leads to dog dermatitis and ear infections. The current treatment for otitis externa, which involves antifungal, antibiotic, and glucocorticoid drugs, faces challenges due to drug resistance and pet owners' compliance with prolonged treatment. This review delves into alternative treatment methods beyond conventional antifungal drugs and provides recommendations for their practical use. These methods include phytotherapies, chemical substances, drug repositioning, ear cleaners, alternative administration methods, and therapeutic diets. Further research, clinical trials, and comparative studies are needed to validate the efficacy of these alternative treatments and incorporate them into clinical practice. By implementing these methods, traditional treatment protocols can be optimized, drug resistance can be minimized, and the management of M. pachydermatis otitis externa in dogs can be improved, following the One Health approach that promotes prudent antimicrobial use.

Antimicrobial Resistance in Escherichia coli Isolated from Healthy Dogs and Cats in South Korea, 2020-2022.

The occurrence of antimicrobial-resistant bacteria in companion animals poses public health hazards globally. This study aimed to evaluate the antimicrobial resistance profiles and patterns of commensal E. coli strains obtained from fecal samples of healthy dogs and cats in South Korea between 2020 and 2022. In total, 843 E. coli isolates (dogs, n = 637, and cats, n = 206) were assessed for susceptibility to 20 antimicrobials. The resistance rates of the most tested antimicrobials were significantly higher in dog than in cat isolates. Cefalexin (68.9%) demonstrated the highest resistance rates, followed by ampicillin (38.3%), tetracycline (23.1%), and cefazolin (18.7%). However, no or very low resistance (0-0.6%) to amikacin, imipenem, piperacillin, and colistin was found in both dog and cat isolates. Overall, 42.3% of the isolates exhibited multidrug resistance (MDR). MDR in isolates from dogs (34.9%) was significantly higher than in those from cats (20.9%). The main components of the resistance patterns were cefalexin and ampicillin in both dog and cat isolates. Additionally, MDR patterns in isolates from dogs (29.2%) and cats (16%) were shown to encompass five or more antimicrobials. Multidrug-resistant commensal E. coli could potentially be spread to humans or other animals through clonal or zoonotic transmission. Therefore, the incidence of antimicrobial resistance in companion animals highlights the urgent need to restrict antimicrobial resistance and ensure the prudent use of antimicrobials in Korea.

Dosage Optimisation of Trimethoprim and Sulfamethoxazole for the Treatment of an Avian Pathogenic Strain of Escherichia coli in Broiler Chickens.

Based on pharmacokinetic studies carried out according to the methodologies defined by the European Medicines Agency (EMA) using mass spectrometry analysis, a new formulation of a veterinary drug for the treatment of broiler chickens is proposed. Currently, the traditional trimethoprim-sulfamethoxazole drug used for broilers is applied in a 1:5 ratio, and the recommended dose is 45 mg kg-1 of live weight administered at 24 h intervals for 3 to 5 days. In this study, we propose a novel combination containing similar active substances in a newly established ratio of 1:4, with a recommended dosage of 20 mg kg-1 of live weight administered at 24 h intervals for 3 to 5 days. With this method, the currently recommended dose of the traditional trimethoprim-sulfamethoxazole drug used for broilers can be reduced by more than half. The efficacy of the newly designed formulation and dosage of the drug was verified in a bioassay for the treatment of broilers experimentally infected with an avian pathogenic strain of Escherichia coli. In the experiment, we compared the newly designed dosage with the traditional dosage in terms of efficacy and dosage. There were no statistically significant differences between the two drugs in efficacy regarding the survival of chickens after experimental infection or changes in their health status. The experimental results suggest that a significant reduction in the recommended daily dose of drugs containing trimethoprim and sulfamethoxazole for the treatment of bacterial infections in broilers is possible and can support the prudent use of antimicrobials, including the limitation of their overuse.

In Vitro Microevolution and Co-Selection Assessment of Florfenicol Impact on Escherichia coli Resistance Development.

The issue of antimicrobial resistance is becoming an increasingly serious challenge in both human and veterinary medicine. Prudent antimicrobial use in veterinary medicine is warranted and supported by international guidelines, with the Antimicrobial Advice Ad Hoc Expert Group (AMEG) placing particular emphasis on the critically important group B antimicrobials. These antimicrobials are commonly employed, especially in the poultry and swine industry. The impact of florfenicol, a veterinary antibiotic, was studied on the resistance development of Escherichia coli. The aim of the study was to investigate the effect of the use of florfenicol on the development of phenotypic and genomic resistances, not only to the drug itself but also to other drugs. The minimum inhibitory concentrations (MICs) of the antibiotics were investigated at 1×, 10×, 100× and 1000× concentrations using the adapted Microbial Evolution and Growth Arena (MEGA-plate) method. The results demonstrate that florfenicol can select for resistance to fluoroquinolone antibiotics (167× MIC value increase) and cephalosporins (67× MIC value increase). A total of 44 antimicrobial resistance genes were identified, the majority of which were consistent across the samples. Chromosomal point mutations, including alterations in resistance-associated and regulatory genes (acrB, acrR, emrR and robA), are thought to trigger multiple drug efflux pump activations, leading to phenotypically increased resistance. The study underscores the impact of florfenicol and its role in the development of antimicrobial resistance, particularly concerning fluoroquinolone antibiotics and cephalosporins. This study is the first to report florfenicol's dose-dependent enhancement of other antibiotics' MICs, linked to mutations in SOS-box genes (mdtABC-tolC, emrAB-tolC and acrAB-tolC) and increased multidrug efflux pump genes. Mutations in the regulatory genes acrR, emrR and rpbA support the possibility of increased gene expression. The results are crucial for understanding antimicrobial resistance and its development, highlighting the promising potential of in vitro evolutionary and coselection studies for future research.

Antimicrobial use practices in canine and feline dental procedures performed in primary care veterinary practices in the United States

This study examined the utilization of antimicrobials in canines and felines receiving dental treatments in veterinary clinics in the United States, retrospectively. A total of 818,150 animals (713,901 procedures in dogs and 104,249 procedures in cats) underwent dental procedures under general anesthesia in 2020. These included dental prophylaxis and extractions. Patient demographic data, antimicrobial treatment, treatment duration, dose, periodontal disease score, whether tooth extractions were performed and how many extractions were performed was recorded. Our results showed that local or systemic antimicrobials were used in 116,723/713,901 (16.4%) procedures in dogs and 14,264/104,249 (14%) procedures in cats. Age, weight, extraction of one or more teeth and diagnosis of periodontal disease (any stage) were associated with increased likelihood of antimicrobial administration using univariable analysis (all P&lt;0.001) and in the multivariable model. Clindamycin, amoxicillin-clavulanate and amoxicillin were the most common oral antimicrobials used in dogs and cats. Drugs classified as highest priority clinically important antibiotics (HPCIA) were administered to 30,960/116,723 (26.5%) of dogs and 7,469/14,264 (52%) of treated cats. The results obtained can inform interventions to optimize patient care and promote prudent use of antimicrobials during dental procedures in canine and feline patients.

Strategies to reduce antimicrobials in livestock and aquaculture, and their impact under field conditions: a structured scoping literature review.

Antimicrobial resistance is a pandemic problem, causing substantial health and economic burdens. Antimicrobials are extensively used in livestock and aquaculture, exacerbating this global threat. Fostering the prudent use of antimicrobials will safeguard animal and human health. A lack of knowledge about alternatives to replace antimicrobials, and their effectiveness under field conditions, hampers changes in farming practices. This work aimed to understand the impact of strategies to reduce antimicrobial usage (AMU) in livestock and aquaculture, under field conditions, using a structured scoping literature review. The Extension for Scoping Reviews of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA-ScR) were followed and the Patient, Intervention, Comparison, Outcome, Time and Setting (PICOTS) framework used. Articles were identified from CAB Abstracts, MEDLINE and Scopus. A total of 7505 unique research articles were identified, 926 of which were eligible for full-text assessment; 203 articles were included in data extraction. Given heterogeneity across articles in the way alternatives to antimicrobials or interventions against their usage were described, there was a need to standardize these by grouping them in categories. There were differences in the impacts of the strategies between and within species; this highlights the absence of a 'one-size-fits-all' solution. Nevertheless, some options seem more promising than others, as their impacts were consistently equivalent or positive when compared with animal performance using antimicrobials. This was particularly the case for bioactive protein and peptides, and feed/water management. The outcomes of this work provide data to inform cost-effectiveness assessments of strategies to reduce AMU.