Swarming populations of Salmonella represent a unique physiological state coupled to multiple mechanisms of antibiotic resistance.
Swarming populations of Salmonella represent a unique physiological state coupled to multiple mechanisms of antibiotic resistance.
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DOI：
10.1251/bpo61
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发表时间：
2003
影响因子：
6.4
通讯作者：
Surette MG
中科院分区：
文献类型：
--
作者：
Kim W;Surette MG
鼠伤寒沙门氏菌能够在半固体表面上大量繁殖。尽管它的集群行为与其他集群细菌有许多容易观察到的相似之处，但这种现象在某种程度上仍然是这种细菌的谜，因为一些属性偏离了更好的特征系统。成群运动与经典的游泳运动是完全不同的，因为细胞首先要经历形态上的转变为成群的细胞。在一些生物中，群体效应是由群体感应控制的，而在另一些生物中，群体效应已被证明与重要毒力因子表达的增加相结合。在鼠伤寒沙门氏菌中蜂拥与对各种结构和功能上不同类别的抗菌化合物的抵抗力增加有关。随着鼠伤寒沙门氏菌分化为群细胞，pmrHFIJKLM操纵子上调，导致更具正电荷的内毒素核心。此外，随着群体细胞开始去分化，PMR操纵子的表达下调，迅速达到在游泳细胞中观察到的水平。这是一种潜在的机制，使群体细胞对阳离子抗菌肽等抗生素的抵抗力增强。然而，更多的机制可能与处于群体状态的细胞有关，这些细胞对如此广泛的抗菌剂具有更高的耐药性。
Salmonella enterica serovar Typhimurium is capable of swarming over semi-solid surfaces. Although its swarming behavior shares many readily observable similarities with other swarming bacteria, the phenomenon remains somewhat of an enigma in this bacterium since some attributes skew away from the better characterized systems. Swarming is quite distinct from the classic swimming motility, as there is a prerequisite for cells to first undergo a morphological transformation into swarmer cells. In some organisms, swarming is controlled by quorum sensing, and in others, swarming has been shown to be coupled to increased expression of important virulence factors. Swarming in serovar Typhimurium is coupled to elevated resistance to a wide variety of structurally and functionally distinct classes of antimicrobial compounds. As serovar Typhimurium differentiates into swarm cells, the pmrHFIJKLM operon is up-regulated, resulting in a more positively charged LPS core. Furthermore, as swarm cells begin to de-differentiate, the pmr operon expression is down-regulated, rapidly reaching the levels observed in swim cells. This is one potential mechanism which confers swarm cells increased resistance to antibiotics such as the cationic antimicrobial peptides. However, additional mechanisms are likely associated with the cells in the swarm state that confer elevated resistance to such a broad spectrum of antimicrobial agents.