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The epidemic of antimicrobial resistant infections continues to challenge, compromising animal care, complicating food animal production and posing zoonotic disease risks. While the overall role of therapeutic antimicrobial use in animals in the development AMR in animal and human pathogens is poorly defined, veterinarians must consider the impacts of antimicrobial use in animal and take steps to optimize antimicrobial use, so as to maximize the health benefits to animals while minimizing the likelihood of antimicrobial resistance and other adverse effects. This consensus statement aims to provide guidance on the therapeutic use of antimicrobials in animals, balancing the need for effective therapy with minimizing development of antimicrobial resistance in bacteria from animals and humans.

Summary: Collateral ligament (CL) desmopathy of the distal interphalangeal joint (DIPJ) is a known injury that is not uncommonly diagnosed in horses presenting for lameness isolated to the foot. Ultrasonography and radiography are often used as primary diagnostic tests with mixed success. Medical records of horses undergoing magnetic resonance imaging (MRI) of the foot between November 2007 and October 2015 were reviewed. Horses were included only if the MRI followed an examination that localised a component of the lameness to the foot, and the MRI study indicated that CL desmopathy of the DIPJ was the most important finding. Thirty‐four limbs from 28 horses were included and 48 CL desmopathies were identified. Of the 48; 27 were distal to the coronary band, 15 were proximal to the coronary band, five lesions involved the entire ligament, and one CL had proximal and distal focal lesions. Twenty‐four of the 28 horses were able to return to work. There was no significant association between severity or lesion location and time to return to work. This study confirms that a high proportion of CL lesions of the DIPJ are located distal to the coronary band and require MRI for an accurate diagnosis that would otherwise be missed by ultrasound examination alone. [ABSTRACT FROM AUTHOR]

Summary: Background: Seizures are a common manifestation of neurological disease in the neonatal foal and are an important cause of morbidity and mortality in this population. Current antiepileptic options are effective, but often have undesirable adverse effects, short duration of action and high cost. Levetiracetam has an ideal safety and pharmacokinetic profile in multiple species, including the adult horse, and may be a safe and cost‐effective alternative anticonvulsant in neonatal foals. Due to differences in drug disposition and clearance dosages in neonates, dosing recommendations in other species or adult horses cannot be extrapolated to foals. Objective: To establish the pharmacokinetic profile of single‐dose i.v. and intragastric administration of levetiracetam in healthy neonatal foals. Study design: Randomised crossover experimental study. Methods: Levetiracetam was administered as a single dose to six healthy foals (ages 1–10 days) at a dose of 32 mg/kg bwt i.v. or intragastrically. Plasma levetiracetam concentrations were measured using a validated HPLC protocol. Results: After i.v. administration to healthy foals, levetiracetam had a mean (±s.d.) elimination half‐life of 7.76 ± 0.51 h, a mean systemic clearance of 61.67 ± 10.96 (mL/h/kg) and a mean apparent volume of distribution at steady state of 0.670 ± 0.124 (L/kg). Following intragastric administration, levetiracetam had a peak concentration of 38.34 ± 7.42 mg/L and time to achieve peak concentration was 0.875 (0.5–1.5) h. Mean bioavailability for IG administration was excellent (103.04 ± 14.51%). No significant differences in pharmacokinetic variables between routes and order of administration were observed. Main limitations: Small sample size and single‐dose administration. Conclusions: Levetiracetam has excellent intragastric bioavailability in foals and is predicted to maintain plasma concentrations at or above the proposed target concentration with twice daily i.v. or oral administration. Once‐daily administration may be possible in some foals based on the therapeutic range recommended in other species. [ABSTRACT FROM AUTHOR]

Summary: Background: Despite the paucity of data available, orally administered angiotensin‐converting enzyme (ACE) inhibitors are empirically used in horses with valvular regurgitation. Objective: Evaluate the echocardiographic and hormonal changes in response to oral benazepril in horses with left‐sided valvular regurgitation. Study design: Prospective, randomised double‐blind, placebo‐controlled trial. Methods: Horses with mitral valve (MR) and/or aortic valve regurgitation (AR) received oral benazepril (n = 6) at a dosage of 1 mg/kg q 12 h or a placebo (n = 5) for 28 days. Echocardiography was performed before drug administration and after 28 days of treatment. Plasma renin activity, serum ACE activity, angiotensin II concentration, aldosterone concentration and biochemical variables were measured before drug administration and after 7 and 28 days of treatment. Results: Relative to baseline, horses treated with benazepril had statistically significant reduction in left ventricular internal diameter in systole (mean difference between groups = −0.97 cm; 95% CI = −1.5 to −0.43 cm), aortic sinus diameter (−0.31 cm; −0.54 to −0.07 cm), and percentage of the aortic annulus diameter occupied by the base of the AR jet (−17.05%; −31.17 to −2.93%) compared with horses receiving a placebo. In addition, horses treated with benazepril had a significantly greater increase in cardiac output (11.95 L/min; 1.17–22.73 L/min) and fractional shortening (7.59%; 3.3–11.88%) compared with horses receiving a placebo. Despite profound serum ACE inhibition, renin activity and concentrations of angiotensin II and aldosterone were not significantly different between treatment groups or among time points. Main limitations: Very small sample size and short treatment period. Conclusions: Treatment with oral benazepril resulted in statistically significant echocardiographic changes that might indicate reduced cardiac afterload in horses with left‐sided valvular regurgitation. Additional studies with a larger sample size will be necessary to determine if administration of benazepril is beneficial in horses with valvular regurgitation. The Summary is available in Spanish – see Supporting Information [ABSTRACT FROM AUTHOR]

Summary: Pneumonia caused by Rhodococcus equi is one of the most important causes of disease and death in foals. R. equi can also be cultured from a large variety of extrapulmonary sites of infection. In the absence of an effective vaccine, ultrasonographic screening for early detection of pulmonary lesions has become routine practice at many farms endemic for pneumonia caused by R. equi. Consequently, the most frequently recognised form of R. equi infection at such farms is a subclinical form in which foals develop sonographic evidence of peripheral pulmonary consolidation or abscessation without necessarily manifesting clinical signs. Evidence exists that not all foals with ultrasonographic lesions will progress to develop clinical signs, and treating a large proportion of foals based on subclinical ultrasonographic findings has been linked to emergence of macrolide‐ and rifampin‐resistant R. equi at a horse farm. Selectively treating only those foals with larger lesion scores and monitoring foals with daily physical inspections and weekly thoracic ultrasonography offers an approach that could decrease antimicrobial drug use without significantly increasing mortality. Current evidence continues to support the combination of rifampin with a macrolide (azithromycin, clarithromycin or erythromycin) for treating clinical infections caused by R. equi despite recently described pharmacological interactions between these drugs. When infection with a macrolide‐resistant isolate is confirmed, limited effective alternatives exist. [ABSTRACT FROM AUTHOR]