The effect of enterococci on feline Tritrichomonas foetus infection in vitro.

Tritrichomonas foetus is a common cause of large bowel diarrhea in cats. Probiotics have been suggested to be effective for many intestinal pathogens; however, there are a lack of studies evaluating the effect of probiotics in T. foetus infection. In vitro studies were performed to evaluate the effect of a probiotic containing Enterococcus faecium (Efm) SF68 and a novel probiotic, Enterococcus hirae, on the inhibition of T. foetus growth, adhesion to, and cytotoxicity towards the intestinal epithelium. The effect of enterococci on T. foetus proliferation during co-culture was evaluated throughout log phase T. foetus growth. The previously validated in vitro co-culture model system using porcine intestinal epithelial cells (IPEC-J2) was used to evaluate the effect of enterococci on T. foetus adhesion and cytotoxicity towards intestinal epithelial cells. Cytotoxicity was assessed using fluorescent microscopy and spectrophotometry. Interactions of T. foetus, enterococci, and intestinal epithelial cells were assessed using scanning electron microscopy and immunofluorescence assays (IFA). Enterococcus-induced inhibition of T. foetus growth was demonstrated at concentrations as low as 104 enterococci colony forming units (CFU)/mL and was dependent, in part, on environmental pH and the presence of viable enterococci organisms. T. foetus adhesion, including with a ronidazole-resistant strain, was reduced with pretreatment of intestinal epithelial cells with enterococci but was not significantly affected when enterococci were introduced simultaneously or following T. foetus infection. Compared to Efm, E. hirae more effectively decreased T. foetus adhesion, suggesting its superior potential as a novel probiotic for T. foetus infection. There was no effect of enterococci treatment on T. foetus-induced intestinal epithelial cell cytotoxicity. Our results support further study into the investigation of a possible benefit of enterococci-containing probiotic treatment for prevention of T. foetus infection in at-risk uninfected cats.

Comparison of heparinized saline and 0.9% sodium chloride for maintaining central venous catheter patency in healthy dogs.

BACKGROUND: The purpose of this study was to determine whether heparinized saline (HS) would be more effective in maintaining the patency of central venous catheters (CVCs) in dogs compared to 0.9% sodium chloride. This was a prospective randomized blinded study conducted at a University Veterinary Teaching Hospital. METHODS: A total of 24 healthy purpose-bred dogs were randomized into two groups: a treatment and a control group. A CVC was placed in the jugular vein of each dog. Each dog in the treatment group had their CVC flushed with 10 IU/mL HS, while dogs in the control group had their CVC flushed with 0.9% sodium chloride every 6 h for 72 h. Immediately prior to flushing, each catheter was evaluated for patency by aspiration of blood. The catheter site was also evaluated for phlebitis, and a rectal temperature was obtained in each dog every 6 h. Prothrombin (PT) and activated partial thromboplastin (aPTT) times were evaluated prior to the administration of any flush solution. Results were then compared to values obtained 72 h later. RESULTS: All CVCs in both groups were patent after 72 h, which was demonstrated by aspiration of blood and ease of flushing the catheter. Two CVCs in the 0.9% sodium chloride group had a negative aspiration at hour 12 and 36, respectively. One CVC in the HS group had a negative aspiration at hour 18. Signs of phlebitis occurred in three dog: two in the 0.9% sodium chloride group and one in the HS group. No dog was hyperthermic (>103 °F). Two catheters were inadvertently removed by dogs in the HS group during the study. There were no significant differences in catheter patency, incidence of phlebitis, or incidence of negative aspirations between both groups. aPTT and PT values remained within the normal reference range for all dogs in both groups. Ultimately, 0.9% sodium chloride was as effective as 10 IU/mL HS in maintaining the patency of CVCs for up to 72 h in healthy dogs. Further evaluation in clinical patients is warranted.

The frequency of oral famotidine administration influences its effect on gastric pH in cats over time.

BACKGROUND: Famotidine is commonly administered to cats. Prolonged famotidine administration results in decreased efficacy in humans, dogs, and cows, but the long-term effects in cats are unknown. OBJECTIVES: To compare the effect of 2 oral administration frequencies of famotidine, twice daily (Group 1) and twice daily every second day (Group 2), on intragastric pH and serum gastrin concentrations in cats. We hypothesized a diminished effect on intragastric pH would be observed over time in Group 1 but not Group 2. ANIMALS: Sixteen healthy cats. METHODS: Randomized, 2-factor repeated measures crossover design. Cats received 0.5-1.24 mg/kg (median, 0.87 mg/kg) famotidine twice daily or twice daily every second day for 14 consecutive days. Intragastric pH monitoring was used to record intragastric pH on treatment days 1-3 and 11-13. Mean pH and mean percentage time (MPT) intragastric pH was ≥3 and 4 were compared between and within treatment groups by analysis of variance. RESULTS: Significant treatment group by time interactions were observed for mean intragastric pH, MPT intragastric pH ≥3 and 4 (P = .009, P = .02, P = .005, respectively). Interaction post hoc tests identified significant decreases in mean intragastric pH (P = .001), MPT ≥3 (P = .001), and MPT ≥4 (P = .001) on day 13 compared to day 1 in Group 1 but not in Group 2. CONCLUSIONS AND CLINICAL IMPORTANCE: Oral famotidine administration results in a diminished effect on intragastric pH in healthy cats when given twice daily every day.