Inhibition of Tritrichomonas foetus growth by broad-spectrum antibiotics

Abstract

Tritrichomonas foetus is a sexually transmitted protozoan that causeshighly damaging reproductive failure in livestock, promptingsome countries to initiate control programs. These programs arebased on the evaluation and exclusion of individual bulls. Nitroimidazolesare effective for controlling the disease, but their use is notrecommended in animals intended for food production. For this reason,one strategy is to find new therapeutic uses for existing drugs,such as antibiotics. Ciprofloxacin is a broad-spectrum antibiotic thatis not known for its effect on protozoa as an inhibitor of T. foetusgrowth. Chloramphenicol inhibits protein synthesis in bacteria andmay have effects on eukaryotic cells, such as inhibiting the growthof T. foetus. Therefore, the objective of this study was to investigatethe efficacy of two broad-spectrum antibiotics, ciprofloxacin andchloramphenicol. To do this, T. foetus trophozoites were incubated inculture medium with serial dilutions of ciprofloxacin or chloramphenicol,and mortality was determined after 24 hours. During this period,the antibiotic ciprofloxacin eliminated all cells with an EC50 of 21.5μg/ml. Chloramphenicol produced the same effect with a maximumeffective concentration (EC50) of 281.0 μg/ml. The results showedeffective inhibition of T. foetus growth at moderate concentrationsof ciprofloxacin. The results showed effective inhibition of T. foetusgrowth at moderate concentrations of ciprofloxacin, whereas highconcentrations of chloramphenicol are required to produce the sameeffect. The results were sensitive under the established experimentalconditions, but evaluation under other experimental conditionsand in the field is required.