Pang Ervinna, Tien-Lin Chang, Selvaraj Madhan, Chang Jason, Kwang Jimmy
Animal Health Biotechnology Group, Temasek Life Sciences Laboratory, National University of Singapore, Singapore.
FEMS Immunol Med Microbiol. 2011 Oct;63(1):108-18. doi: 10.1111/j.1574-695X.2011.00834.x. Epub 2011 Jul 29.
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major food-borne pathogen. From a transposon insertion mutant library created previously using S. Enteritidis 10/02, one of the mutants was identified to have a 50% lethal dose (LD(50) ) at least 100 times that of the parental strain in young chicks, with an attenuation in a poorly studied gene encoding a component of pyruvate dehydrogenase, namely the aceE gene. Evaluation of the in vitro virulence characteristics of the ΔaceE∷kan mutant revealed that it was less able to invade epithelial cells, less resistant to reactive oxygen intermediate, less able to survive within a chicken macrophage cell line and had a retarded growth rate compared with the parental strain. Young chicks vaccinated with 2 × 10(9) CFU of the ΔaceE∷kan mutant were protected from the subsequent challenge of the parental strain, with the mutant colonized in the liver and spleen in a shorter time than the group infected with the parental strain. In addition, compared with the parental strain, the ΔaceE∷kan mutant did not cause persistent eggshell contamination of vaccinated hens.
肠炎沙门氏菌肠炎血清型（肠炎沙门氏菌）是一种主要的食源性病原体。从先前使用肠炎沙门氏菌10/02构建的转座子插入突变体文库中，鉴定出其中一个突变体在幼雏中的半数致死剂量（LD50）至少是亲本菌株的100倍，该突变体中一个研究较少的编码丙酮酸脱氢酶组分的基因即aceE基因发生了衰减。对ΔaceE∷kan突变体的体外毒力特性评估显示，与亲本菌株相比，它侵袭上皮细胞的能力较弱，对活性氧中间体的抵抗力较弱，在鸡巨噬细胞系内存活的能力较弱且生长速率较慢。用2×10⁹CFU的ΔaceE∷kan突变体对幼雏进行疫苗接种后，可使其免受亲本菌株随后的攻击，该突变体在肝脏和脾脏中的定殖时间比感染亲本菌株的组短。此外，与亲本菌株相比，ΔaceE∷kan突变体不会导致接种疫苗的母鸡出现蛋壳持续污染的情况。
