Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka 1212, Bangladesh.
Proc Natl Acad Sci U S A. 2013 Jun 11;110(24):9926-31. doi: 10.1073/pnas.1307697110. Epub 2013 May 28.
Cholera epidemics have long been known to spread through water contaminated with human fecal material containing the toxigenic bacterium Vibrio cholerae. However, detection of V. cholerae in water is complicated by the existence of a dormant state in which the organism remains viable, but resists cultivation on routine bacteriological media. Growth in the mammalian intestine has been reported to trigger "resuscitation" of such dormant cells, and these studies have prompted the search for resuscitation factors. Although some positive reports have emerged from these investigations, the precise molecular signals that activate dormant V. cholerae have remained elusive. Quorum-sensing autoinducers are small molecules that ordinarily regulate bacterial gene expression in response to cell density or interspecies bacterial interactions. We have found that isolation of pathogenic clones of V. cholerae from surface waters in Bangladesh is dramatically improved by using enrichment media containing autoinducers either expressed from cloned synthase genes or prepared by chemical synthesis. These results may contribute to averting future disasters by providing a strategy for early detection of V. cholerae in surface waters that have been contaminated with the stools of cholera patients or asymptomatic infected human carriers.
霍乱疫情长期以来一直被认为是通过受到人类粪便污染的水传播的，这些粪便中含有产毒细菌霍乱弧菌。然而，由于存在休眠状态，水 中霍乱弧菌的检测变得复杂，在这种休眠状态下，该生物体仍然具有活力，但在常规细菌培养基上难以培养。据报道，在哺乳动物肠道中的生长会引发这种休眠细胞的“复苏”，这些研究促使人们寻找复苏因子。尽管这些研究中有一些积极的报告，但激活休眠霍乱弧菌的确切分子信号仍然难以捉摸。群体感应自动诱导物是一类小分子，通常根据细胞密度或种间细菌相互作用来调节细菌的基因表达。我们发现，通过使用含有自动诱导物的富集培养基，从孟加拉国地表水分离出致病性霍乱弧菌克隆，其分离效果得到了显著提高，这些自动诱导物要么来自克隆的合成酶基因表达，要么通过化学合成制备。这些结果可能有助于避免未来的灾难，提供了一种在受到霍乱患者粪便或无症状感染人类携带者污染的地表水早期检测霍乱弧菌的策略。
