Long E G, Ewing E P, Bartlett J H, Horsburgh C R, Birkness K A, Yakrus M A, Newman G W, Quinn F D
Division of AIDS, STD and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
FEMS Microbiol Lett. 2000 Sep 15;190(2):267-72. doi: 10.1111/j.1574-6968.2000.tb09297.x.
Eight-day-old embryonated hen's eggs were used as a model to study Mycobacterium avium virulence. Strains isolated from human patients caused 20-90% mortality when eggs were infected by injection of bacterial suspensions into the amniotic sac. Virulence of examined strains subsequently decreased with passage through eggs to between 0 and 40% mortality in four passages. Virulence of the egg-attenuated strains could be restored by passage through human peripheral blood mononuclear cells. The site of infection in the egg was usually the mesodermal layer of the chorioallantoic membrane. A few small granulomas containing acid-fast bacteria were seen in the liver, but not in other organs. Death of chicken embryos may have resulted from destruction of the mesodermal layer of the chorioallantoic membrane with consequent respiratory failure. PBMCs infected with less virulent egg-passaged strains of M. avium produced higher levels of tumor necrosis factor-alpha than did peripheral blood mononuclear cells infected with more virulent nonpassaged strains.
以8日龄鸡胚作为模型来研究鸟分枝杆菌的毒力。从人类患者分离出的菌株，当通过向羊膜腔内注射细菌悬液感染鸡胚时，可导致20% - 90%的死亡率。随后，所检测菌株的毒力随着在鸡胚中传代而降低，在传代4次后死亡率降至0至40%。经鸡胚减毒的菌株通过人外周血单个核细胞传代后，其毒力可恢复。鸡胚中的感染部位通常是绒毛尿囊膜的中胚层。在肝脏中可见少数含有抗酸菌的小肉芽肿，但在其他器官中未发现。鸡胚死亡可能是由于绒毛尿囊膜中胚层遭到破坏，进而导致呼吸衰竭。与感染毒力较强的未传代菌株的外周血单个核细胞相比，感染毒力较弱的经鸡胚传代菌株的外周血单个核细胞产生的肿瘤坏死因子-α水平更高。
