Diagnostic performance and application of a real-time PCR assay for the detection of Salmonella in fecal samples collected from hospitalized horses with or without signs of gastrointestinal tract disease.

The main objective of this study was to assess the diagnostic performance of a real-time polymerase chain reaction (PCR) assay for the detection of Salmonella in fecal samples collected from hospitalized horses with or without signs of gastrointestinal (GI) tract disease. The PCR assay used primers and a probe that targeted the invA gene of Salmonella. Assuming a sensitivity of 100% and a specificity of 96.6%, and a disease prevalence of 2%, 5%, and 10-15% in study horses, the PCR assay had a high (100%) negative predictive value, and a positive predictive value that ranged from 37% in horses without signs of GI disease that tested Salmonella culture-negative, to 60% in horses with signs of GI disease that tested Salmonella culture-negative, to 76-83% in horses with signs of GI disease that tested Salmonella culture-positive. This study provides evidence that the real-time PCR that targets the Salmonella invA gene can be used as a screening test for the detection of Salmonella in feces of hospitalized horses with signs of GI disease. Horses that test PCR-positive can be tested in series using bacteriologic culture to reduce false positive results or to provide additional data (e.g., antibiogram and serotyping data) that can be used to identify potential nosocomial Salmonella infections.

Neurological signs and pre- and post-traction low-field MRI findings in Dobermanns with disc-associated cervical spondylomyelopathy.

OBJECTIVE: To investigate whether the presence of neurological signs and magnetic resonance imaging findings could predict the presence of a traction-responsive lesion in Dobermanns affected by disc-associated cervical spondylomyelopathy. METHODS: Retrospective review of neurological signs and low-field pre- and post-traction magnetic resonance imaging abnormalities of the cervical spine (abnormal vertebral body shape and vertebral tipping, intervertebral disc degeneration, protrusion and ligamentum flavum hypertrophy) in Dobermanns with disc-associated cervical spondylomyelopathy. The main outcome of interest was response to linear traction (dynamic versus static) at C6-C7 intervertebral disc space. The association between investigated variables and response to linear traction was assessed. RESULTS: The study included 25 dogs. No association was identified between neurological status grading and the presence of a static or traction-responsive lesion. Of the investigated magnetic resonance findings, C7-T1 intervertebral disc degeneration was significantly (P = 0 · 03) associated with the presence of a traction-responsive lesion at C6-C7 intervertebral disc space. CLINICAL SIGNIFICANCE: The presence of C7-T1 intervertebral disc degeneration might help in predicting the presence of traction-responsive C6-C7 intervertebral disc lesions.

Cardiovascular effects of N-butylscopolammonium bromide and xylazine in horses.

REASONS FOR PERFORMING STUDY: N-butylscopolammonium bromide (NBB) and xylazine are commonly used medications for the treatment of spasmodic colic and other forms of abdominal pain in horses. Both NBB and xylazine exert significant effects on the cardiovascular system and other vital systems of horses. OBJECTIVE: To evaluate the effects of i.v. administration of NBB, xylazine, and the combination of NBB and xylazine on heart rate, other commonly measured physiological parameters, cardiac rhythm and blood pressure. METHODS: Six mature horses of mixed breed were used. In a random cross-over design, each horse was given 0.3 mg/kg bwt of NBB i.v., 0.25 mg/kg bwt xylazine i.v., and a combination of 0.3 mg/kg bwt NBB and 0.25 mg/kg bwt xylazine. Heart rate, physiological parameters, cardiac rhythm and indirect blood pressure were recorded at timed intervals before and 60 min following administration. RESULTS: Heart rate and blood pressure were significantly elevated immediately following administration of NBB or NBB with xylazine. Administration of NBB with xylazine resulted in significantly greater initial and peak blood pressure values than with NBB alone. Administration of xylazine resulted in a decrease in heart rate, with an initial increase in blood pressure followed by a decrease in blood pressure. Sinus tachycardia was seen with NBB, and NBB and xylazine administration. First and second degree atrioventricular block was identified with xylazine administration. Ventricular tachycardia was identified in one horse following NBB and xylazine administration. CONCLUSIONS: Results of this study suggest that the effects of administration of NBB alone or in combination with xylazine to horses with colic, especially to those with systemic cardiovascular compromise, should be considered carefully to assess condition and predict prognosis accurately, and to avoid potential adverse effects.