Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Antimicrobial Resistance
Antimicrobial resistance in horses refers to the ability of microorganisms to withstand the effects of antimicrobial agents that are intended to inhibit or kill them. This phenomenon occurs when bacteria, viruses, fungi, or parasites evolve mechanisms to resist the actions of drugs, leading to reduced efficacy of treatments. In equine medicine, antimicrobial resistance can complicate the management of infections, impacting both animal health and treatment strategies. The development and spread of resistant strains are influenced by factors such as the overuse or misuse of antimicrobial agents in veterinary practice. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, prevalence, and implications of antimicrobial resistance in equine populations.
Equine blood cultures: Can we do better? Blood culture is considered the gold standard test for documenting bacteraemia in patients with suspected bacterial sepsis in veterinary and human medicine. However, blood culture often fails to yield bacterial growth even though the clinical picture is strongly suggestive of bacterial sepsis, or contaminating organisms can overgrow the true pathogen, making accurate diagnosis and appropriate management of this life-threatening condition very challenging. Methodology for collecting blood cultures in equine medicine, and even in human hospitals, is not standardised, and many variables can affec...
Antimicrobial resistance among Streptococcus equi subspecies zooepidemicus and Rhodococcus equi isolated from equine specimens submitted to a diagnostic laboratory in Kentucky, USA. Surveillance of antimicrobial resistance (AMR) among veterinary pathogens is necessary to identify clinically relevant patterns of AMR and to inform antimicrobial use practices. Streptococcus equi subsp. zooepidemicus and Rhodococcus equi are bacterial pathogens of major clinical importance in horses and are frequently implicated in respiratory tract infections. The objectives of this study were to describe antimicrobial resistance patterns and identify predictors of AMR and multidrug resistance (MDR) (resistance to three or more antimicrobial classes) among equine S. zooepidemicus and R. equi...
Rhodococcus equi foal pneumonia: Update on epidemiology, immunity, treatment and prevention. Pneumonia in foals caused by the bacterium Rhodococcus equi has a worldwide distribution and is a common cause of disease and death for foals. The purpose of this narrative review was to summarise recent developments pertaining to the epidemiology, immune responses, treatment, and prevention of rhodococcal pneumonia of foals. Screening tests have been used to implement earlier detection and treatment of foals with presumed subclinical R. equi pneumonia to reduce mortality and severity of disease. Unfortunately, this practice has been linked to the emergence of antimicrobial-resistant R. equi i...
Antimicrobial Susceptibility of Bacterial Isolates from Donkey Uterine Infections, 2018-2021. Endometritis is a common reproductive disease in equine animals. No investigation about the bacterial characteristics and antimicrobial susceptibility pattern of donkeys with endometritis has thus far been reported. Objective: To determine the common uterine bacterial isolates from donkeys with endometritis and to evaluate their susceptibility to antimicrobials used for the treatment thereof. Methods: Retrospective case-series. Methods: Medical records at an equine clinical diagnostic center were retrospectively reviewed to identify submissions from donkeys with bacterial endometritis between ...
Analysis of Virulence and Antimicrobial Resistance Gene Carriage in Staphylococcus aureus Infections in Equids Using Whole-Genome Sequencing. While Staphylococcus aureus is associated with significant morbidity and mortality in equids (horses, donkeys, and mules), few studies have performed whole-genome sequencing to fully categorize large collections of equine isolates. Such sequencing allows for a comprehensive analysis of the genetic lineage and relationships of isolates, as well as the virulence genes present in each, which can be important for understanding the epidemiology of strains and their range of infections. Seventy-two clinical Staphylococcus aureus isolates from equids were collected at the Texas A&M University Vet...
Antimicrobial Resistance Spectrum Conferred by pRErm46 of Emerging Macrolide (Multidrug)-Resistant Rhodococcus equi. Clonal multidrug resistance recently emerged in Rhodococcus equi, complicating the therapeutic management of this difficult-to-treat animal- and human-pathogenic actinomycete. The currently spreading multidrug-resistant (MDR) "2287" clone arose in equine farms upon acquisition, and coselection by mass macrolide-rifampin therapy, of the pRErm46 plasmid carrying the (46) macrolide-lincosamide-streptogramin resistance determinant, and of an mutation. Here, we screened a collection of susceptible and macrolide-resistant strains from equine clinical cases using a panel of 15 antimicrobials agains...
Whole genome sequencing of methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolated from 4 horses in a veterinary teaching hospital and its ambulatory service. Genomic characterization was conducted on 2 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 2 horses hospitalized during an overlapping period of time and 2 methicillin-sensitive S. aureus (MSSA) strains isolated from 2 distinct horses. Phylogenetic proximity was traced and the genotypic and phenotypic characteristics of the antimicrobial resistance of the strains were compared. Whole genome sequencing of MRSA strains for this report was similar but differed from whole genome sequencing of MSSA strains. The MRSA strains were closely related, belonging to sequence type ...
Antimicrobial prescribing patterns in equine ambulatory practice. Antimicrobial resistance is one of the most important public health risks facing our world today. Antimicrobials are commonly prescribed in equine veterinary medicine, but limited information exists documenting their use in practice. The goal of this study was to investigate antimicrobial prescription patterns in regards to prescription frequency, duration, drug class, clinician and affected body system in an equine ambulatory setting via retrospective analysis of billing and electronic medical records. Risk factors associated with antimicrobial prescription including the nature of the visit, ...
Evaluation of the Bactericidal Effect of Nebulized Silver Nanoparticles on Common Respiratory Bacteria in Horses- In Vitro Studies. Antimicrobial resistance is increasing in both human and veterinary medicine. Bacteria can be part of the etiology of respiratory disorders in horses. Bactericidal activity of silver has been largely described and silver is currently used in veterinary therapeutic applications such as wound dressings. The aim of this study was to assess the in vitro bactericidal effects of nebulized silver nanoparticles (AgNP) on 2 common equine respiratory bacteria, Streptococcus equi subsp. zooepidemicus and Actinobacillus equuli subsp. equuli. Firstly, antimicrobial susceptibility of AgNP was determined ove...
Association between antimicrobial treatment of subclinical pneumonia in foals and selection of macrolide- and rifampicin-resistant Rhodococcus equi strains at horse-breeding farms in central Kentucky. To compare soil concentrations of macrolide- and rifampicin-resistant strains (MRRE) on horse-breeding farms that used thoracic ultrasonographic screening (TUS) to identify foals with subclinical pneumonia combined with subsequent administration of macrolides and rifampin to affected foals (TUS farms) versus soil concentrations on farms that did not (non-TUS farms), determine whether the combined use of TUS and antimicrobial treatment of subclinically affected foals was associated with soil concentration of MRRE, and assess whether there were temporal effects on soil concentrations of MRRE du...
Equine antimicrobial therapy: Current and past issues facing practitioners. Equine antimicrobial therapy has advanced over time with the availability of increasing pharmacokinetic and pharmacodynamic studies in horses, allowing for greater evidence-based clinical decision-making. However, many challenges to optimal antimicrobial therapy remain and further research is needed to address these areas. There are a limited number of approved antimicrobials for use in horses, which creates a need for compounded preparations for clinicians. Extra-label drug use is commonplace in equine practice, which warrants continual education of veterinarians about policies and updates. P...
Plasma lipidome of healthy and Rhodococcus equi-infected foals over time. Many foals that develop thoracic ultrasonographic lesions as a result of Rhodococcus equi infection heal on their own. However, most of these foals receive antimicrobials because foals at risk of developing clinical pneumonia cannot be identified. Untargeted lipidomics is useful to identify candidate biomarkers. Objective: (a) To describe the changes that occur in foal lipidomics as a result of ageing (birth to 8 weeks) and (b) To compare these results with those observed in foals after experimental infection with R. equi. Methods: Experimental study. Methods: Healthy newborn foals (n = 9) ...
Faecal microbiota and antimicrobial resistance gene profiles of healthy foals. The human and domestic animal faecal microbiota can carry various antimicrobial resistance genes (ARGs), especially if they have been exposed to antimicrobials. However, little is known about the ARG profile of the faecal microbiota of healthy foals. A high-throughput qPCR array was used to detect ARGs in the faecal microbiota of healthy foals. Objective: To characterise the faecal microbiota and ARG profiles in healthy Australian foals aged less than 1 month. Methods: Observational study. Methods: The faecal microbiota and ARG profiles of 37 Thoroughbred foals with no known gastrointestinal ...
Antimicrobial-Resistant Enterococcus faecium and Enterococcus faecalis Isolated From Healthy Thoroughbred Racehorses in Japan. In this study, the occurrence of antimicrobial-resistant (AMR) enterococci was evaluated in Thoroughbred (TB) racehorses in Japan. Fecal samples were collected from 212 healthy TB racehorses at the Miho and Ritto Training Centers of the Japan Racing Association from March 2017 to August 2018. Isolation and identification were performed by enterococcus selective medium and confirmed to the species using MALDI-TOF MS. Enterococcus faecium and E. faecalis isolates were subjected to antimicrobial susceptibility test against 11 antimicrobials by minimum inhibitory concentration based on recommenda...
DNA microarray-based characterization and antimicrobial resistance phenotypes of clinical MRSA strains from animal hosts. Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe infections in humans and animals worldwide. Studies elucidating the population structure, staphylococcal cassette chromosome mec types, resistance phenotypes, and virulence gene profiles of animal-associated MRSA are needed to understand spread and transmission. Objective: The objective of this study was to determine 1) clonal complexes and spa types, 2) resistance phenotypes, and 3) virulence/resistance gene profiles of MRSA isolated from animals in Switzerland. Methods: We analyzed 31 presumptive MRSA isolates co...
Gram-positive bacteriocins: usage as antimicrobial agents in veterinary medicine. Antimicrobial resistance is a worldwide spread phenomenon that affects both human and veterinary medicine. This issue has led to a "One Health" approach in order to coordinate efforts and set back the development of drug-resistant microbes. In the search for alternatives therapies, bacteriocins or antimicrobial peptides have proven to be effective both in vitro and in vivo for multiples pathogens, even those resistant to many classic antibiotics. Gram-positive bacteriocins have been the most studied to the present. The use of bacteriocins as therapeutically active molecules is limited mainly d...
Antimicrobial Resistance in Horses. Antimicrobial resistance (AMR) is an increasingly recognized global public health threat to the modern health-care system that could hamper the control and treatment of infectious diseases [...].
Antimicrobial Usage in Horses: The Use of Electronic Data, Data Curation, and First Results. The usage of antimicrobial drugs (AMs) leads to an increase in antimicrobial resistance (AMR). Although different antimicrobial usage (AMU) monitoring programs exist for livestock animals in Germany, there is no such system for horses. However, with the increasing usage of electronic practice management software (EPMS), it is possible to analyze electronic field data generated for routine purposes. The aim of this study was to generate AMU data for German horses with data from the Clinic for Horses (CfH), University of Veterinary Medicine Hannover (TiHo), and in addition to show that different...
Horizontal Spread of Rhodococcus equi Macrolide Resistance Plasmid pRErm46 across Environmental Actinobacteria. Conjugation is one of the main mechanisms involved in the spread and maintenance of antibiotic resistance in bacterial populations. We recently showed that the emerging macrolide resistance in the soilborne equine and zoonotic pathogen is conferred by the (46) gene carried on the 87-kb conjugative plasmid pRErm46. Here, we investigated the conjugal transferability of pRErm46 to 14 representative bacteria likely encountered by in the environmental habitat. mating experiments demonstrated conjugation to different members of the genus as well as to and spp. at frequencies ranging from ∼10...
Horses as a Crucial Part of One Health. One Health (OH) is a crucial concept, where the interference between humans, animals and the environment matters. This review article focusses on the role of horses in maintaining the health of humans and the environment. Horses' impact on environmental health includes their influence on soil and the biodiversity of animal and plant species. Nevertheless, the effect of horses is not usually linear and several factors like plant-animal coevolutionary history, climate and animal density play significant roles. The long history of the relationship between horses and humans is shaped by the servic...
Comparing PFGE, MLST, and WGS in monitoring the spread of macrolide and rifampin resistant Rhodococcus equi in horse production. Rhodococcus equi (R. equi) infections are endemic in many horse facilities in the United States resulting significant economic loses annually. Currently, there is no commercial vaccine available and the emergence of isolates that are resistant to the current treatment and prophylaxis using antibiotics prompts closer surveillance of this pathogen. Objective: This study compares three different genotyping techniques, Pulsed Field Gel Electrophoresis (PFGE), Multilocus Sequence Typing (MLST) and whole genome SNP-based phylogeny to determine the most accurate method to monitor the spread of macrol...
Prevalence and risk factors associated with emergence of Rhodococcus equi resistance to macrolides and rifampicin in horse-breeding farms in Kentucky, USA. The combination of a macrolide and rifampicin has been the mainstay of therapy in foals with Rhodococcus equi pneumonia for decades. Recent studies suggest that mass antimicrobial treatment of subclinically affected foals over time has selected for antimicrobial resistance. Our objective was to estimate the prevalence of R. equi strains resistant to macrolides and rifampicin at horse breeding farms in Kentucky. A hundred breeding farms in Kentucky were surveyed and R. equi were cultured from soil samples. Data were analyzed with logistic regression and generalized linear modeling (P < 0...
Transfusion With 2 L of Hyperimmune Plasma is Superior to Transfusion of 1 L or Less for Protecting Foals Against Subclinical Pneumonia Attributed to Rhodococcus equi. Transfusing foals with Rhodococcus equi hyperimmune plasma (REHIP) is a standard practice at many horse-breeding farms to help prevent R. equi pneumonia. At many large breeding farms, pneumonia is most commonly recognized as subclinical based on thoracic ultrasonography findings. The efficacy of REHIP transfusion and the impact of the volume of plasma transfused for reducing the cumulative incidence of subclinical R. equi pneumonia are unknown. A retrospective cohort study was conducted among foals born and residing through weaning at a large breeding farm. Foals were transfused with either ...
Enterococcus infections in foals. Enterococci have been increasing in prevalence in foal sepsis over the past three decades. There are no published studies in the peer-reviewed literature documenting common sites of infection, antimicrobial susceptibility, or outcome specifically associated with enterococcal infections in foals. Our objectives were to evaluate the sites of origin, antimicrobial susceptibility, and survival outcome to discharge in foals with enterococcal infections compared with foals with sepsis of another bacterial etiology. Seventy-five foals 0-30 days of age with cultures positive for Enterococcus and 170 c...
Effect of Macrolide and Rifampin Resistance on the Fitness of Rhodococcus equi. is a leading cause of severe pneumonia in foals. Standard treatment is dual antimicrobial therapy with a macrolide and rifampin, but the emergence of macrolide- and rifampin-resistant isolates is an increasing problem. The objective of this study was to determine the effect of macrolide and/or rifampin resistance on fitness of Three unique isogenic sets were created, each consisting of four strains, as follows: a susceptible parent isolate, strains resistant to macrolides or rifampin, and a dual macrolide- and rifampin-resistant strain. Each isogenic set's bacterial growth curve was genera...
Genomic characterization and comparative analysis of Leptospira kirschneri serogroup Grippotyphosa UC5/2011, a strain isolated after mare abortion: Implications for genital animal leptospirosis. The genome of a Brazilian strain of Leptospira kirschneri serogroup Grippotyphosa isolated from a mare post-abortion was sequenced and analyzed. High symmetrical identity and few structural differences were found when compared with a European strain of the same serogroup, L. kirschneri serovar Valbuzzi strain 200702274. Genes associated with virulence and antimicrobial resistance were found. Knowledge of the virulence evolution of Leptospira remains limited, especially in diseases of the reproductive sphere. We highlight the importance of virulence studies in the sphere of genital leptospirosi...
Surveillance for Salmonella in horses in Great Britain. Francesca Martelli, Sue Kidd and Joanna Lawes of the APHA discuss surveillance findings relating to Salmonella isolates from horses, and also the antimicrobial resistance patterns being seen.
