Dynamics of growth and death within a Salmonella typhimurium population during infection of macrophages
Dynamics of growth and death within a Salmonella typhimurium population during infection of macrophages
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DOI：
10.1139/m97-005
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发表时间：
1997-01-01
影响因子：
2.8
通讯作者：
Libby, SJ
中科院分区：
文献类型：
--
作者：
Buchmeier, NA;Libby, SJ
鼠伤寒沙门氏菌在巨噬细胞内的存活与毒力相关。大多数关于沙门氏菌在巨噬细胞感染期间的命运的数据来自细胞内细菌的活菌计数。这些计数是细胞内细菌死亡和生长的结果，但可能不能反映沙门氏菌巨噬细胞杀伤或细胞内细菌生长的真实水平。在这项研究中，两种独立的方法已被用来获得更准确的测量绝对水平的死亡和生长的沙门氏菌内巨噬细胞。嘌呤营养缺陷型（purD）用于测量沙门氏菌死亡的细菌生长的情况下，然后通过补充腺苷purD培养物测量细菌生长。死亡和活沙门氏菌的数量也使用BacLight染色系统进行定量，该系统可区分死亡细菌和活细菌。这两种方法都表明，巨噬细胞对沙门氏菌的杀灭作用远远大于使用传统细胞计数检测到的杀灭作用，并且在整个感染期间发生细菌灭活。沙门氏菌在J774巨噬细胞（最允许的巨噬细胞）和腹膜渗出液巨噬细胞（最不允许的巨噬细胞）中以相似的速率灭活，表明这些细胞之间的主要差异是限制细菌生长的能力。这些研究还表明，鼠巨噬细胞内沙门氏菌的生长与大量细菌死亡同时发生。确定负责将巨噬细胞和细菌之间的相互作用转向有利于细菌生长的条件的因素对于理解沙门氏菌的毒力至关重要。
Survival of Salmonella typhimurium within macrophages is associated with virulence. Most data on the fate of Salmonella during infection of macrophages are derived from viable counts of intracellular bacteria. These counts are a result of a combination of bacterial death and growth within the intracellular population but may not reflect the true levels of either macrophage killing of Salmonella or bacterial growth inside cells. In this study, two independent methods have been used to obtain a more accurate measurement of absolute levels of both death and growth of Salmonella inside macrophages. A purine auxotroph (purD) was used to measure Salmonella death in the absence of bacterial growth and then bacterial growth was measured by supplementing the purD cultures with adenosine. Numbers of dead and live Salmonella were also quantitated using the BacLight staining system, which distinguishes dead from live bacteria. Both methods demonstrate that killing of Salmonella by macrophages is considerably greater than detected using traditional cell counts and that bacterial inactivation occurs throughout the infection period. Salmonella was inactivated at a similar rate in both J774 macrophages (most permissive macrophages) and peritoneal exuadate macrophages (least permissive macrophages), suggesting that the major difference between these cells is the ability to limit bacterial growth. These studies also demonstrate that growth of Salmonella within murine macrophages occurs simultaneously with significant amounts of bacterial death. Identifying the factors responsible for shifting the interaction between macrophages and bacteria toward conditions that favor bacterial growth will be critical to understanding Salmonella virulence.