Hendrixson David R, DiRita Victor J
Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA.
Mol Microbiol. 2004 Apr;52(2):471-84. doi: 10.1111/j.1365-2958.2004.03988.x.
Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans in developed countries throughout the world. This bacterium frequently promotes a commensal lifestyle in the gastrointestinal tracts of many animals including birds and consumption or handling of poultry meats is a prevalent source of C. jejuni for infection in humans. To understand how the bacterium promotes commensalism, we used signature-tagged transposon mutagenesis and identified 29 mutants representing 22 different genes of C. jejuni strain 81-176 involved in colonization of the chick gastrointestinal tract. Among the determinants identified were two adjacent genes, one encoding a methyl-accepting chemotaxis protein (MCP), presumably required for proper chemotaxis to a specific environmental component, and another gene encoding a putative cytochrome c peroxidase that may function to reduce periplasmic hydrogen peroxide stress during in vivo growth. Deletion of either gene resulted in attenuation for growth throughout the gastrointestinal tract. Further examination of 10 other putative MCPs or MCP-domain containing proteins of C. jejuni revealed one other required for wild-type levels of caecal colonization. This study represents one of the first genetic screens focusing on the bacterial requirements necessary for promoting commensalism in a vertebrate host.
空肠弯曲菌是全球发达国家人类细菌性肠胃炎的主要病因。这种细菌常在包括鸟类在内的许多动物的胃肠道中营共生生活方式，食用或处理禽肉是人类感染空肠弯曲菌的常见来源。为了解该细菌如何促进共生，我们使用了签名标签转座子诱变技术，并鉴定出29个突变体，它们代表空肠弯曲菌81-176菌株中参与雏鸡胃肠道定殖的22个不同基因。鉴定出的决定因素包括两个相邻基因，一个编码甲基接受趋化蛋白（MCP），可能是对特定环境成分进行正确趋化所必需的，另一个基因编码一种假定的细胞色素c过氧化物酶，其可能在体内生长过程中发挥作用以减轻周质过氧化氢应激。删除任何一个基因都会导致在整个胃肠道中的生长减弱。对空肠弯曲菌的其他10个假定的MCP或含MCP结构域的蛋白质进行进一步研究发现，另一个是盲肠定殖达到野生型水平所必需的。这项研究是首批聚焦于在脊椎动物宿主中促进共生所需细菌条件的遗传筛选之一。
