A quarterly Survey of antibiotic prescribing in small animal and equine practices-Minnesota and North Dakota, 2020.

Antimicrobials are critical for medicine, but the problem of antimicrobial resistance (AMR) threatens the effectiveness of these valuable drugs. In USA, there are no national- or state-level programs or policies in place to track antibiotic use (AU) in dogs, cats, and horses, despite acknowledgement of this sector's importance to both the AMR problem and its solution. AU measurement is a key part of antibiotic stewardship and AMR prevention. This study aimed to fill existing gaps in the veterinary professions' knowledge of antibiotic prescribing in small animals and horses. To address this aim, medical record data were collected on a single day per quarter for 1 year from 19 Minnesota and North Dakota small animal and equine practices, totaling 1,899 veterinarian consults of dogs, cats, and horses. Overall, 25.8% of all canine, feline, and equine consults involved an antibiotic prescription. Third-generation cephalosporins were the most commonly prescribed systemic antibiotic drug class, and the long-acting injectable drug, cefovecin, was the most commonly prescribed antibiotic for cats (34.5%). Topical antibiotic preparations were prescribed frequently, especially in dogs (42.5% of canine prescriptions), though systemic antibiotics were often prescribed concurrently. Common general indications, based on problem or diagnosis recorded in the medical record, for antibiotics in all species combined were skin conditions (24.4%), otitis (22.1%), ophthalmic (9.4%), gastrointestinal (8.3%), respiratory (8.3%), and urinary tract (7.6%) diseases. While 44.2% of patients for which antibiotics were prescribed had cytology performed, only 3.9% had bacterial culture and susceptibility performed. In a pre-study survey, veterinarians' recommendations for AU differed from actual prescribing, suggesting collection of AU data provides more accurate assessments of veterinary prescribing behaviour than surveys. This study shows feasibility of AU measurement in small animals and horses. The data collection tool and standard operating procedures described prove suitable for national AU data collection.

Cloning and tissue expression of the equine transferrin receptor.

BACKGROUND: Characterization of anemia in horses presents a challenge, as they do not release reticulocytes into peripheral blood. Transferrin receptor (TfR) expression is highest on erythroid cells in people and rats, and measurement of a soluble serum form (sTfR) is used to quantify erythropoiesis in these species. We hypothesized that equine TfR (eTfR) expression is similar in quantity and distribution to that in these other species and thus has potential for characterization of the regenerative response in anemic horses. OBJECTIVE: This study was conducted to clone and sequence the eTfR gene and measure expression levels using quantitative real-time PCR and immunohistochemical (IHC) staining. METHODS: Total RNA from equine bone marrow was used to produce cDNA. The eTfR gene was amplified using pooled gene-specific primers, and PCR products were sequenced. Rapid amplification of cDNA ends was used to obtain the first 22 nucleotides of the coding sequence. Quantitative PCR was performed using eTfR gene-specific primers, and IHC staining was used to localize TfR protein expression. RESULTS: The deduced amino acid (aa) sequence (767 aa) of the eTfR was 75-83% identical with sequences of the receptor in several other mammals. As in people and rats, eTfR mRNA expression was highest in the bone marrow, and distribution in other tissues was also similar. CONCLUSION: The eTfR gene is similar to that of other mammals in structure and expression levels. We hypothesize that it is also similar in function and that, following development of an immunoassay, determining sTfR concentrations will be useful for identifying the regenerative response in anemic horses.

Comparison of methods for depletion of albumin and IgG from equine serum.

BACKGROUND: Disease-specific biomarkers hold diagnostic promise in both human and veterinary medicine, but serum biomarkers in low concentrations may be masked by the presence of abundant proteins, mostly albumin and IgG. Methods to deplete albumin and IgG exist, but efficacy of these methods for depleting equine serum of these proteins has not been established. OBJECTIVE: The aim of this study was to determine if albumin and IgG could be depleted from equine serum using several commercially available kits and procedures. METHODS: One-dimensional gel electrophoresis followed by densitometry was used to determine percent of albumin, IgG, and both in pooled serum from 3 horses before and after application of 7 depletion methods. Repeatability was determined by applying the 2 best methods to serum samples from 6 grade horses. RESULTS: For pooled serum, depletion rates varied from 35-90% for albumin and 0-94% for IgG. In the repeatability study, the ProteoExtract method combined with protein G Sepharose beads to remove additional IgG provided the best overall performance with 66% albumin depletion and 100% IgG depletion. A protocol using protein G Sepharose beads to remove IgG followed by ethanol precipitation of nonalbumin proteins with albumin remaining in the supernatant was the second most effective, with 85% albumin depletion and 55% IgG depletion. Although a multiprotein immunodepletion column effectively removed 90% of the albumin, the method was ineffective at removing IgG. CONCLUSION: Albumin and IgG removal kits optimized for human use have variable efficacy for equine serum. Combined use of the ProteoExtract kit and manual incubation with protein G Sepharose beads provided the most effective depletion.