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- Author or Editor: Jonathan E. Palmer x
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Abstract
Objective—To assess microorganisms isolated from blood specimens obtained from critically ill neonatal foals and to evaluate their antimicrobial susceptibility patterns.
Design—Retrospective study.
Animals—543 neonatal foals.
Procedure—Medical records of foals that were < 1 month old and were admitted to a referral neonatal intensive care unit were reviewed for results of bacteriologic culture of blood and antimicrobial susceptibility patterns.
Results—At least 1 microorganism was isolated from 155 of 543 (28.5%) foals. Escherichia coli was the most commonly isolated bacterium. A single grampositive organism was detected in 49 foals. Although 90% of the E coli isolates were susceptible to amikacin, some gram-negative and gram-positive organisms had resistance against multiple antimicrobials.
Conclusions and Clinical Relevance—Gram-negative bacteria remain the most common isolates from blood of neonatal foals; however, gram-positive organisms were also found, and with greater prevalence than reported elsewhere. Susceptibility patterns may vary, and resistance to multiple antimicrobials may develop. This is especially true for organisms such as Enterobacter spp and Enterococcus spp. Prudent empirical treatment for neonatal sepsis should include broad-spectrum antimicrobials. (J Am Vet Med Assoc 2001;218:1608–1610)
Objective
To determine prevalence of clostridial enterotoxins in feces of horses with diarrhea and colic, and to determine whether an association exists between detection of clostridial enterotoxins in feces and development of diarrhea as a complication of colic.
Design
Prospective case series and case-control study.
Animals
174 horses with diarrhea, colic, or problems not related to the gastrointestinal tract.
Procedure
Horses were assigned to 1 of 4 groups: colic with diarrhea (group 1; n = 30); colic without diarrhea (group 2; 30); diarrhea without colic (group 3; 57); and control (group 4; 57). Feces were evaluated by use of ELISA to detect Clostridium perfringens enterotoxin (CPE) and C difficile toxin A (TOXA). Frequency of detection of CPE or TOXA in groups 1 and 3 was compared with that in groups 2 and 4, respectively.
Results
Prevalence of enteric clostridiosis in horses in group 3 was 25%. Clostridium perfringens enterotoxin was detected in 9 of 57 (16%), TOXA in 8 of 57 (14%), and both toxins in 3 of 57 (5%) fecal samples collected from these horses. Neither toxin was detected in feces of the age-matched horses in group 4. Clostridial enterotoxins were detected in feces of 7 of 60 (12%) horses with colic (groups 1 and 2); however, a significant association was not found between detection of enterotoxins in feces and development of diarrhea as a complication of colic.
Conclusions and Clinical Relevance
Clostridia are important etiologic agents of diarrhea in horses. Additionally, changes in intestinal flora of horses with colic may allow for proliferation of clostridia and elaboration of enterotoxins regardless of whether diarrhea develops. (J Am Vet Med Assoc 1999;215:358–361)
Summary
The medical records of 23 American Miniature Horses with hyperlipidemia, hyperlipemia, or hepatic lipidosis were reviewed. The most common clinical signs were anorexia and lethargy. The mean duration of clinical signs was 2.4 days. A primary disease was identified in 19 cases. Enterocolitis was the most common primary disease (n = 10). Intentional feed restriction, as part of treatment for colic, resulted in hyperlipemia in 2 horses and hyperlipidemia in 1. Four horses had primary hyperlipemia, 3 of which had signs of hepatoencephalopathy secondary to hepatic lipidosis. Dextrose, heparin, and insulin were the most common treatments. The overall survival was 61% (14/23). All horses with peak serum triglyceride concentrations > 1,200 mg/dl died or were euthanatized, whereas all but 1 with peak serum triglyceride concentrations < 1,200 mg/dl survived. These findings suggest that when American Miniature Horses, like other ponies and donkeys, are in a negative energy balance, they can rapidly develop hyperlipidemia or hyperlipemia. Early detection and treatment may improve survival.
Objective—
The original objective was to determine seroprevalence of Ehrlichia risticii antibody among horses in California. On the basis of the unexpected results of the survey, an investigation into the accuracy and reproducibility of results of the indirect fluorescent antibody ( ifa) test for E risticii was carried out.
Design—
Prospective, seroprevalence study.
Animals—
Healthy horses (n = 655) and horses with clinical signs of equine monocytic ehrlichiosis ( eme; n = 514) from various regions of California.
Procedure—
The ifa test was performed. Results were compared with results of an elisa and with results of western immunoblot analysis.
Results—
Overall, 104 of 655 (15.9%) healthy horses had evidence of an antibody response. However, 84 of 514 (16.3%) horses with clinical signs of eme also had positive test results, and of the 8 seropositive diseased horses for which paired (acute and convalescent) samples had been submitted, only 1 had a rise in antibody titers between the acute and convalescent samples. Comparison of results for the ifa test, elisa, and western immunoblot analysis revealed a high rate of false-positive results for the ifa test. Subsequent studies suggested that routine vaccination of horses with non-E risticii vaccines may have contributed to the false-positive reactions.
Clinical Implications—
The data failed to provide conclusive evidence of E risticii infection among California horses. Owing to the high percentage of false-positive test results, caution is advised when using the ifa test to diagnose eme in horses or to determine the necessity for E risticii vaccination.
Summary
A Latin square design was used to compare the effects of laxatives and a corresponding volume of water on gastrointestinal tract function in 4 healthy horses. Horses were intragastrically infused with each of the following: dioctyl sodium sulfosuccinate (dss; 50 mg/kg of body weight); magnesium sulfate (0.5 g/kg—low dosage); magnesium sulfate (1.0 g/kg—high dosage); and an equal volume of water (6 L) given as a control infusion. From 5 to 33 hours after the high dosage of magnesium sulfate, feces were slightly softer than usual in all horses. In 1 horse, dss caused mild colic, hyperpnea, and diarrhea from 0.3 to 3 hours after administration. After all laxative treatments and the control infusion, fecal output, fecal water, number of defecations, and fecal water percentage were greater during the first 6 and 12 hours, compared with each subsequent 6-hour period (P < 0.05). The high dosage of magnesium sulfate had greater effect on fecal output and fecal water than did the low dosage and control infusion (P < 0.05). However, this effect preceded arrival of the liquid transit marker, polyethylene glycol, and magnesium at their highest concentrations in feces by 12 to 18 hours. Compared with the control infusion, none of the laxative treatments affected excretion of polyethylene glycol and plastic particulate markers, nor did they increase water consumption.
It was concluded that the response to intragastric infusions may involve reflex mechanisms in the gastrointestinal tract and that these responses could be used for treatment of colon impactions. Under conditions of this study, dss was not a sufficiently effective laxative to outweigh the risk of toxic effects at recommended doses. Although dss and the low dosage of magnesium sulfate may not provide a greater laxative effect than did an equal volume of water, the high dosage of magnesium sulfate should be more effective.
Abstract
Objective—To review management of pregnant mares with body wall defects and assess the effect of various management strategies on the outcome of mares and their foals.
Design—Retrospective case series.
Animals—13 mares.
Procedures—Medical records of eligible mares were reviewed. Signalment, history, admitting complaint, clinical findings, parity, type of body wall defect, concurrent diagnoses, postpartum complications, outcome of fetus, outcome of mare, and type of clinical case management were recorded.
Results—8 mares received conservative management and 5 mares received interventional management. Survival of mares to discharge was good, and no difference in mare survival was identified on the basis of type of management, type of body wall defect, or presence of hydrops. Foal survival was significantly better in the conservative management group, compared with those managed by interventional management, and was also better without hydrops.
Conclusions and Clinical Relevance—Foal survival can be improved in mares with body wall defects that occur during parturition without compromising mare survival by use of conservative management strategies that avoid induction of parturition or elective caesarian section and allow for natural parturition. Potentially, improved fetal readiness for birth may play a role.
Abstract
Case Description—A 1-day-old Standardbred foal with a history of extreme respiratory distress after birth consistent with upper airway obstruction was evaluated. A temporary tracheostomy tube was placed by the referring veterinarian.
Clinical Findings—On initial examination, there was evidence of hypoxic-ischemic syndrome, secondary to perinatal asphyxia. Endoscopy revealed obstruction of both nares at the level of the choanae; a diagnosis of bilateral choanal atresia was made.
Treatment and Outcome—The foal was anesthetized and underwent transendoscopic laser fenestration of the buccopharyngeal membranes. Three weeks after surgery, cicatricial narrowing of the choanae was apparent and further transendoscopic ablation was performed. Recurrent stenosis necessitated revision surgeries involving a combination of laser ablation with topical administration of mitomycin and, subsequently, a combination of radial incisions into the stenotic tissue and repeated bougienage with a cuffed endotracheal tube. The degree of stenosis decreased, and at 1 year of age, the horse was an appropriate size for its age, had choanae that were almost maximally open (> 85%), and had entered training. Mild stenosis was still evident when the horse was reexamined the following year, although there was no evidence of exercise intolerance or respiratory compromise.
Clinical Relevance—Bilateral choanal atresia in a foal can be successfully treated via transendoscopic fenestration of the buccopharyngeal membranes, enabling the horse to subsequently participate in athletic activities. Secondary problems resulting from initial asphyxia and recurrent stenosis at the surgical site can be overcome but may require prolonged and extensive treatment.
