Use of a commercially available culture system for diagnosis of Tritrichomonas foetus infection in cats

Objective-To evaluate the efficacy of and optimize a commercially available culture system for sensitive and specific in-clinic culture of Tritrichomonas foetus from cat feces. Design-Prospective study. Sample Population-Samples of freshly voided feces from 117 purebred cats and pure cultures of T foetus obtained from a cat with chronic diarrhea. Procedure Optimal conditions for use of the culture system, such as quantity of fecal inoculum (0.025 to 0.2 g) and cultivation temperature (25 or 37degreesC [98.6 or 77.0degreesF]), were determined. Specificity of the system was examined by attempted culture of Giardia lamblia and Pentatrichomonas hominis. Sensitivity of the system to detect T foetus was determined by inoculation of culture system pouches with serially diluted T foetus suspensions with and without feces. Results-Detection limit of the culture system was 1 and 1,000 T foetus organisms without and with feces from cats, respectively. Optimal fecal inoculum was < 0.1 g of feces. At 37degreesC, cultures yielded positive results in 24 hours; organisms remained viable for 1 to 6 days, and bacterial overgrowth was common. At 25degreesC, cultures yielded positive results in 1 to 11 days; organisms were long-lived, and bacterial overgrowth was uncommon. Neither G lamblia or P hominis survived in the culture system. Conclusions and Clinical Relevance-The culture system was sensitive and specific for culture of T foetus in feces of cats. Performance was optimal when test kits were inoculated with less than or equal to 0.1 g of freshly voided feces and cultured at 25degreesC.