婴幼儿配方粉中肺炎克雷伯菌分离菌株毒力

目的 了解婴幼儿配方粉中肺炎克雷伯菌的毒力强弱及其感染所致病理变化。方法 将5株从婴幼儿配方粉中分离得到的肺炎克雷伯菌和1株标准菌制成不同浓度菌悬液,腹腔注射实验小鼠,计算其半数致死量(LD₅₀);观察染毒小鼠临床症状,解剖死亡小鼠,取其内脏制作病理切片观察病理变化。结果 各分离菌株和标准菌株的LD₅₀分别为3.031、2.638、1.516、2.638、1.516和1.516 McF/kg BW,染毒小鼠体内多器官发生明显病理变化,尤以肺脏和肝脏病变最为明显。结论 婴幼儿配方粉中污染的肺炎克雷伯菌具有较强的毒力并会对婴幼儿健康构成潜在危害。

Virulence of Klebsiella pneumoniae isolated from infant formula milk powder in mice

Objective To evaluate the virulence of Klebsiella pneumoniae isolated from infant formula milk powder and to observe the pathological changes caused by the bacteria.Methods Median lethal dose(LD₅₀) was calculated by injecting different concentrated suspensions of a Klebsiella pneumoniae standard strain and five strains isolated from infant formula milk powder samples into mice abdominal cavity.The clinical symptoms of the injected mice were observed and the pathological changes of died mice were observed with gross anatomy and pathologic section preparation.Results The LD₅₀ for the five isolated strains and the standard strain were 3.031, 2.638, 1.516, 2.638, 1.516 and 1.516 McFarland(McF)/kg BW, respectively.Many organs and tissues of the injected mice presented obvious pathological changes, and the damages of lung and liver were more serious.Conclusion Klebsiella pneumoniae isolated from infant formula milk powder has strong virulence, and their contamination may result in potential hazards to infants.