Enterococcus inhibit growth and adhesion of feline Tritrichomonas foetus
Rachel E. Dickson1, Maggie Daves1, David A. Bemis1, Thomas Cecere2, Jody Gookin3, Julie Vose1, M. Katherine Tolbert1
1University of Tennessee College of Veterinary Medicine, Knoxville, TN
2Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
3North Carolina State College of Veterinary Medicine, Raleigh, NC
Tritrichomonas foetus (Tf) causes chronic diarrhea in cats. Limited treatment options and increasing resistance support investigation of alternative treatments. Probiotics have emerged as adjunct therapies for many intestinal pathogens; however, little work has been done to investigate their efficacy against Tf infection.
Commercial Enterococcus faecium (Efm) and a novel probiotic, Enterococcus hirae (Eh), were used to evaluate efficacy in the inhibition of Tf growth and adhesion in vitro. The effect of Enterococcus on Tf proliferation was evaluated throughout log phase growth in co-culture media. The potential of probiotics to reduce Tf adhesion to intestinal epithelium was analyzed with a previously validated co-culture model using porcine intestinal epithelial cells (IPEC-J2). Tf adhesion and cytotoxicity were evaluated using fluorescent microscopy and crystal violet spectrophotometric analysis. SEM and IFA were used to visualize the interactions of Tf, Enterococcus, and IPEC-J2 monolayers. Data were analyzed using SigmaStat.
Enterococcus-induced inhibition of Tf growth was observed at concentrations as low as 10:1 Tf:Efm (p <0.001) and was determined to be largely pH dependent (p <0.01). Inhibition of Tf replication was not observed when co-cultured with heat-killed Enterococcus, indicating viable Enterococcus organisms were required for inhibition. Pretreatment of IPEC-J2 monolayers with Enterococcus significantly reduced Tf- induced cytopathogenicity (p =0.002). This benefit was not observed when Enterococcus was introduced simultaneously or following Tf infection. These findings suggest that pre-treatment of at-risk cats with probiotics containing Enterococci may alleviate clinical illness resulting from subsequent Tf infection. Eh more effectively decreased Tf adhesion to the intestinal epithelium as compared to Efm (p <0.001), suggesting its superiority as a novel probiotic in Tf infection. Preliminary results also showed Eh was effective at reducing growth and adhesion of a ronidazole-resistant strain of Tf. These results support further investigation of the efficacy of probiotics as an adjunct treatment to combat Tf infection in cats.
University of Tennessee College of Veterinary Medicine
Thursday, June 14
11:15 AM – 11:30 AM
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