Objective The relationship between fitness and single nucleotide gene polymorphism of Yersinia pestis was investigated. Methods In this paper, the mechanism of GTG in competition between different strains was revealed through continuous in vitro co-incubation competition and in vitro static competition. Results With the increase of passage times, GTG strain quickly became the absolute dominant strain and showed competitive adaptability. Under different stresses (Asp deficiency, weak acid and high salt), GTG and TTG strains showed more remarkable adaptability. In the competitive survival test of macrophages, the ratio of GTG strains to TTG strains did not change significantly. In the intracellular competitive amplification product experiment, mice with GTG: TTG=10: 1, the average dose exceeded the theoretical value during the administration process, resulting in early death of the mice. Conclusion GTG has competitive adaptability among different strains. There was no significant difference between the fitness of GTG and TTG strains in the intracellular competition of macrophages and the competition in mice, but TTG strains showed a fitness advantage in E. coli competition.

Yersinia pestis  /  gene polymorphism  /  fitness