... . It has antiemetic activity from dopaminergic blockade in the CTZ. But because very little domperidone crosses the blood-brain barrier, reports of extrapyramidal reactions are rare, and treatment is the same as for metoclopramide. Domperidone failed to enhance gastric emptying in healthy dogs in one study. In other studies, however, domperidone was superior to metoclopramide in stimulating antral contractions in dogs but not cats and improved antroduodenal coordination in dogs. Because of its favorable safety profile, domperidone appears to be an attractive alternative to metoclopramide. Macrolide antibiotics, including erythromycin and clarithromycin, are motilin receptor agonists. They also appear to stimulate cholinergic and noncholinergic neuronal pathways to stimulate motility. At microbially ineffective doses, some macrolide antibiotics stimulate migrating motility complexes and antegrade peristalsis in the proximal GI tract. Erythromycin therapy has been effective in the treatment of gastroparesis in human patients in whom metoclopramide or domperidone was ineffective. Erythromycin increases gastric emptying rate in healthy dogs, but large food chunks may enter the small intestine and be inadequately digested. Erythromycin induces contractions from the stomach to the terminal ileum and proximal colon ...

... diet and antibiotic therapy. Other host factors that may determine whether disease develops include age, immunity, and presence or absence of intestinal receptors for the clostridial toxins. C difficile produces protein toxin A or B or both in the intestine. Toxin A is an enterotoxin that causes hypersecretion of fluid into the intestinal lumen and also causes tissue damage. Toxin B is a potent cytotoxin that induces inflammation and necrosis. Recent antibiotic therapy is a common feature of the history of horses with C difficile -induced diarrhea. Certain antibiotics, notably erythromycin, Î ²-lactam antibiotics, and trimethoprim / sulfonamide, are more likely than others to be associated with C difficile colitis. Mares with foals that are being treated with erythromycin appear to be at high risk. Elimination of roughage from the diet prior to surgery is also reported to predispose to C difficile colitis. C perfringens type A is believed to cause diarrhea by elaboration of an enterotoxin (CPE ), which is released during sporulation and stimulates intestinal epithelial cells to secrete excess fluid into the lumen. A novel necrotizing toxin, called Î ...

... lethargic and darkened. Typical lesions include grayish, localized, or conglomerate granulomata in the viscera, especially the kidney or body wall; exophthalmos; blindness; and emaciation. A presumptive diagnosis can be based on visualization of small gram-positive rods in kidney imprints. Definitive diagnosis requires isolation and identification of the bacteria by using a selective medium that contains cysteine and incubating at 15 C for 3-6 wk. R salmoninarum is transmitted both horizontally and vertically, and fish that survive an epizootic remain carriers. Infected female fish should be injected with erythromycin (11-20 mg / kg, IM) 14-60 days before spawning to prevent vertical transmission. Erythromycin (100 mg / kg for 10-21 days) is efficacious when administered in feed early in the course of an outbreak; however, it is not FDA approved for this use. Obtaining disease-free stock and preventing contamination by infected wild fish are the best preventive measures. Gram positive bacteria of concern to fish culturists and aquarists include Streptococcus and related genera, Lactococcus, Enterococcus, and Vagococcus. Infections caused by these organisms are uncommon but can ...

... inflammation. Neutrophilic leukocytosis and hyperfibrinogenemia are common, and the severity of these findings relates to prognosis. Thoracic radiographic evaluation may reveal a pattern of perihilar alveolization, consolidation, and abscessation. The presence of nodular lung lesions and mediastinal lymphadenopathy in foals 1-5 mo of age is highly suggestive of R equi. Bacterial culture of transtracheal wash samples is required for definitive diagnosis. Cytologic evaluation of transtracheal wash samples reveals intracellular coccobacilli, identification of which indicates initiation of appropriate antimicrobial therapy pending culture results. Treatment and Prognosis: The combination of erythromycin (25 mg / kg, PO, qid; esters or salts) and rifampin (5 mg / kg, bid, or 10 mg / kg, sid) is the treatment of choice. These antimicrobials may be bacteriostatic, but their activity is synergistic, and the combination has markedly improved survival of foals. Idiosyncratic hyperthermia and tachypnea can occur with erythromycin administration during periods of warm environmental conditions, and anorexia, bruxism, and salivation may be observed. Life-threatening, antibiotic-induced enterocolitis, due to Clostridium difficile, has been observed ...