Diagnostic and commensal Staphylococcus pseudintermedius genomes reveal niche adaptation through parallel selection of defense mechanisms.

Staphylococcus pseudintermedius is historically understood as a prevalent commensal and pathogen of dogs, though modern clinical diagnostics reveal an expanded host-range that includes humans. It remains unclear whether differentiation across S. pseudintermedius populations is driven primarily by niche-type or host-species.

Revision of fluoroquinolone breakpoints used for interpretation of antimicrobial susceptibility testing of canine bacterial isolates.

The fluoroquinolone antimicrobial agents, enrofloxacin and marbofloxacin, were US Food and Drug Administration (FDA) approved in the United States for use in dogs in 1988 and 1999, respectively. There have been many advances since then concerning the pharmacokinetic-pharmacodynamic (PK-PD) evaluation of fluoroquinolones, and there are data available on the susceptibility of targeted pathogens since the original approval. Using this information, the Clinical and Laboratory Standards Institute (CLSI) Veterinary Antimicrobial Susceptibility Testing Subcommittee (VAST) revised its antimicrobial susceptibility testing breakpoints.

Benefits and challenges of creating veterinary antibiograms for empiric antimicrobial selection in support of antimicrobial stewardship and advancement of one-health goals.

Antibiograms are important tools for antimicrobial stewardship that are often underutilized in veterinary medicine. Antibiograms summarize cumulative antimicrobial susceptibility testing (AST) data for specific pathogens over a defined time period; in veterinary medicine, they are often stratified by host species and site of infection. They can aid practitioners with empiric therapy choices and assessment of antimicrobial resistance trends within a population in support of one-health goals for antimicrobial stewardship.

Antimicrobial use in 20 U.S. beef feedyards: 2018-2019.

The objective of this study was to report antimicrobial use in a convenience sample of U.S. beef feedyards for the years 2018 and 2019.

Application and Interpretation of Antimicrobial Susceptibility Testing.

Antimicrobial susceptibility testing (AST) is an important component of antimicrobial stewardship. This article discusses how AST methods and breakpoints are developed, describes when AST may or may not be useful in clinical practice, and discusses how to interpret AST results from bacterial isolates from cattle, sheep, and goats. Discussion of when AST is not appropriate or when veterinarians should have low confidence in AST results is also included.

Using telehealth clinical case vignettes to enhance clinical confidence and competence in veterinary students.

Veterinarians contribute substantially to the health of their patients and enhance the communities in which they live. Delivery of veterinary curricula continues to evolve to ensure that veterinary graduates are prepared to meet their professional obligations on Day One of their careers. In this study, veterinary practitioners were recruited to deliver telehealth case rounds to veterinary students at Kansas State University and Texas A&M University.

The association of multiple metrics for evaluating antimicrobial use in U.S. beef feedyards.

In order to accurately portray antimicrobial use in food animals, the need for standardized metrics, and an understanding of the characteristics of different metrics, has long been recognized. Fourteen U.S.

Improving farm-level antimicrobial stewardship benchmarks by reporting antimicrobial use within the context of both the magnitude of disease pressure and the outcome of therapy.

This manuscript explores a method of benchmarking antimicrobial use within the context of farm level therapeutic incidence (a proxy for disease incidence), and the outcome of that therapy. This is reported both within the same farm over time (2016-2019), as well as evaluated across participating farms. Reporting antimicrobial use in this format addresses multiple primary questions necessary for evaluating on farm antimicrobial stewardship: How much disease is recorded? How much antimicrobial use is recorded? How often are antimicrobials included in therapy for each disease? What is the outcome of therapy? The three primary metrics reported are: therapeutic events per 100 cow years (TE/100CY), antimicrobial regimens per 100 cow years (REG/100CY), and the percent therapeutic success (% Success).

Synergistic combinations of clarithromycin with doxycycline or minocycline reduce the emergence of antimicrobial resistance in Rhodococcus equi.

Background: The alarming increase in rifampin and macrolide resistance among Rhodococcus equi isolates highlights the need to identify alternative therapeutic options that can effectively control rhodococcosis in foals while limiting the further development of drug resistance.

Objectives: To evaluate bacterial killing, antibiotic synergism and mutant prevention concentrations (MPCs) of clarithromycin alone and in combination with doxycycline, minocycline or rifampin against clinical isolates of R equi.

Study Design: In vitro experiments.

Detection of bovine inflammatory cytokines IL-1β, IL-6, and TNF-α with a multiplex electrochemiluminescent assay platform.

Commercially available bovine-specific assays are limited in number, and multiplex assays for this species are rare. Our objective was to develop a multiplex assay for the bovine inflammatory cytokines IL-1β, IL-6, and TNF-α using the Meso Scale Discovery U-PLEX platform. "Do-It-Yourself" ELISA kits that contained polyclonal antibodies, both unlabeled and biotinylated, and the specific recombinant bovine cytokine standard, were purchased for each of these three cytokines.

Cytokine and Haptoglobin Profiles From Shipping Through Sickness and Recovery in Metaphylaxis- or Un-Treated Cattle.

Fifty-six head of cattle, 28 animals with bovine respiratory disease complex (BRDC), and 28 healthy animals that were matched by treatment, sale barn of origin, day, and interactions among these variables, were identified from a population of 180 animals (60 each purchased at three sale barns located in Missouri, Tennessee, and Kentucky) enrolled in a study comparing animals receiving metaphylaxis to saline-treated controls. Cattle were transported to a feedlot in KS and assigned to treatment group. Blood samples were collected at Day 0 (at sale barn), Day 1, Day 9, and Day 28 (at KS feedlot), and transported to the US Meat Animal Research Center in Clay Center, NE where plasma was harvested and stored at -80°C until assayed for the cytokines IFN-γ, IL-1β, IL-6, and TNF-α, and the acute stress protein haptoglobin (HPT).

Genomics accurately predicts antimicrobial resistance in Staphylococcus pseudintermedius collected as part of Vet-LIRN resistance monitoring.

Whole-genome sequencing (WGS) has changed our understanding of bacterial pathogens, aiding outbreak investigations and advancing our knowledge of their genetic features. However, there has been limited use of genomics to understand antimicrobial resistance of veterinary pathogens, which would help identify emerging resistance mechanisms and track their spread. The objectives of this study were to evaluate the correlation between resistance genotypes and phenotypes for Staphylococcus pseudintermedius, a major pathogen of companion animals, by comparing broth microdilution antimicrobial susceptibility testing and WGS.

Pharmacological considerations of antibiotic failures in bovine respiratory disease cases.

Bovine respiratory disease (BRD) is one of the most common indications for antimicrobial therapy in beef cattle production and research trials demonstrate that antibiotic therapy greatly improves clinical outcome for BRD. These trials also show that BRD treatment success rates are less than 100% and that there are opportunities to optimize antimicrobial prescribing and improve clinical outcomes if the underlying cause(s) of BRD treatment failures can be identified and addressed. As the etiology of BRD in an individual animal is frequently multi-factorial in nature; it is likely that BRD treatment failures also result from complex interactions between the drug, drug administrator, animal host, pathogens, and the environment.

Antimicrobial use quantification in adult dairy cows - Part 2 - Developing a foundation for pharmacoepidemiology by comparing measurement methods.

As stewardship programmes seek to influence therapeutic choices and reduce resistance selection pressure, it is essential to understand the multiple factors which may influence any given antimicrobial use measure. This article compares 9 measures of antimicrobial use pertaining to adult cows in US dairy systems based on treatment records standardized to a single standardized regimen (SReg) format. There are 3 fundamental parameters underlying the nine measures: amount of active substance (AMOUNT), number of SRegs (ANIMALS) and treatment time (TIME).

Antimicrobial use quantification in adult dairy cows - Part 1 - Standardized regimens as a method for describing antimicrobial use.

This study describes a process to acquire and convert farm treatment records into a standardized regimen format. Multiple sources of on-farm data were utilized to convert the original treatment records to standardized regimens, enabling the generation of objective, granular descriptions of antimicrobial use. These standard regimen descriptions allow antimicrobial use data to be qualitatively stratified by active substance, disease syndrome treated, use category, and route of administration.

Antimicrobial use quantification in adult dairy cows - Part 3 - Use measured by standardized regimens and grams on 29 dairies in the United States.

This study describes antimicrobial use in terms of standardized regimens per cow year (REG/CY) and grams per cow year (GMS/CY) for 29 dairies in the United States during the years 2016 and 2017. To explore potential priorities for antimicrobial stewardship programs, these measures were stratified by both disease syndrome and antimicrobial class. Potential confounders of use measurements are discussed and challenges for measure interpretation are identified.

Comparison of surveys and use records for quantifying medically important antimicrobial use in 18 U.S. Beef Feedyards.

The objective of this study was to evaluate agreement between medically important antimicrobial use metrics derived from in-person surveys of feedyard management as opposed to metrics derived from production unit-level antimicrobial use records. Survey respondents were asked to estimate values which would allow calculation of the metrics of regimens per animal year (Reg/AY) and milligrams of antimicrobial per kilogram of liveweight sold (mg/kg-LW). At the study level, values were calculated by antimicrobial class within the use categories of in-feed use, control of bovine respiratory disease (BRD) and individual animal treatment.

Antimicrobial use in 22 U.S. beef feedyards: 2016-2017.

This study describes antimicrobial use in 22 U.S. beef feedyards by use of two metrics: milligrams of antimicrobial per kilogram of liveweight sold (mg/kg-LW) and antimicrobial regimens per animal year (Reg/AY).

Differences between predicted outer membrane proteins of genotype 1 and 2 Mannheimia haemolytica.

Background: Mannheimia haemolytica strains isolated from North American cattle have been classified into two genotypes (1 and 2). Although members of both genotypes have been isolated from the upper and lower respiratory tracts of cattle with or without bovine respiratory disease (BRD), genotype 2 strains are much more frequently isolated from diseased lungs than genotype 1 strains. The mechanisms behind the increased association of genotype 2 M.

Classification of 16S rRNA reads is improved using a niche-specific database constructed by near-full length sequencing.

Surveys of microbial populations in environmental niches of interest often utilize sequence variation in the gene encoding the ribosomal small subunit (the 16S rRNA gene). Generally, these surveys target the 16S genes using semi-degenerate primers to amplify portions of a subset of bacterial species, sequence the amplicons in bulk, and assign to putative taxonomic categories by comparison to databases purporting to connect specific sequences in the main variable regions of the gene to specific organisms. Due to sequence length constraints of the most popular bulk sequencing platforms, the primers selected amplify one to three of the nine variable regions, and taxonomic assignment is based on relatively short stretches of sequence (150-500 bases).

Bovine Respiratory Disease Treatment Failure: Impact and Potential Causes.

Bovine respiratory disease (BRD) is often attributed to complex interactions between the host, pathogen, and the environment. Likewise, many BRD treatment failures result from interactions between the host, pathogen, environment, drug, and drug administrator. Investigating and addressing the underlying causes of BRD treatment failures can improve clinical outcomes and animal welfare of future cases, improve morale of employees, reduce direct costs of dealing with BRD treatment failures, refine antimicrobial prescribing practices, and advance antimicrobial stewardship.

Current and future perspectives on the categorization of antimicrobials used in veterinary medicine.

The emergence of antimicrobial resistance in human and veterinary bacterial pathogens has led to concerns regarding the use of antimicrobials in veterinary medicine. Consequently, regulatory agencies have developed procedures for assessing the risk associated with the use of a specific antimicrobial as part of the drug approval process. Due consideration for the importance (priority categorization) of the antimicrobial to human medicine is part of this risk assessment process.