Surveillance of Bacterial Intestinal diseases in Southeast Asian countries

从鼠伤寒沙门氏菌LT 2中克隆了复苏促进因子（Rpf）的编码基因。鼠伤寒沙门氏菌LT 2 rpf基因长696 bp，与肠道沙门氏菌Oranienburg血清型（99.4%）有一个保守片段。rRpf不仅促进增殖，而且以剂量依赖性方式诱导VNC（活的但不可培养的）细胞复苏至可培养状态。因此，rRpf可用于检测食品样品和环境中以VNC形式存在的细菌污染物（Panutdaporn N.等人，Int.J.Food Microbiol.一百零六：在1998年日本发生的由盐腌鲑鱼卵引起的肠出血性大肠杆菌（EHEC）O 157：H7爆发中，食物分离物（F2）是NaCl抗性的，而患者分离物（P5）对NaCl敏感。过氧化氢酶，如NaCl，诱导P5的可培养性的显着损失。BacLight检测表明，EHEC O 157：H7进入活但不可培养（VNC）状态。小鼠传代的F2的同基因变异体成为NaCl和氧化敏感，进入非培养状态，以响应这些压力，并可以复苏丙酮酸钠。体内传代负调节RpoS表达，随后的应激暴露诱导EHEC O 157：H7分离株的VNA状态（Asakura H.等人，FEMS Microbiol.Lett. 253：243-249，2005）。

A gene encoding the resuscitation-promoting factor (Rpf) from Salmonella Typhimurium LT2 was cloned and characterized. The S.Typhimurium LT2 rpf gene is 696 bp long, and shared a conserved segment with Salmonella enterica serovar Oranienburg (99.4%). The rRpf not only promoted proliferation but also induced resuscitation of VNC (viable but non-culturable) cells to the culturable state in a dose-dependent manner. Therefore, rRpf may be useful for detection of bacterial contaminants present in the VNC form in food samples and the environment (Panutdaporn N. et al, Int.J.Food Microbiol. 106 : 241-247, 2006).In an enterohemorrhagic Escherichia coli (EHEC) O157:H7 outbreak caused by salted salmon roe that occurred in Japan, 1998, a food isolate (F2) was NaCl-resistant and a patient isolate (P5) was sensitive to NaCl. Hydrogen peroxidase, like NaCl, induced a significant loss of culturability in P5. The BacLight assay suggested that the EHEC O157:H7 entered a viable but non-culturable (VNC) state. Mouse-passaged isogenic variants of F2 became NaCl- and oxidation-sensitive, entered the non-culturable state in response to either of these stresses, and could be resuscitated by sodium pyruvate. In vivo passage negatively modulated RpoS expression, and the subsequent stress exposure induced the VNA state in the EHEC O157:H7 isolates (Asakura H. et al, FEMS Microbiol.Lett. 253 : 243-249, 2005).