Surveillance of Bacterial Intestinal diseases in Southeast Asian countries

克隆并鉴定了鼠伤寒沙门氏菌LT2中复苏促进因子（Rpf）的编码基因。鼠伤寒沙门氏菌LT2 rpf基因全长696 bp，与Oranienburg肠炎沙门氏菌（99.4%）共享一个保守片段。rRpf不仅能促进增殖，还能诱导VNC（活但不可培养的）细胞复苏至可培养状态，且呈剂量依赖性。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. et al ., intj . food microbiology . 106: 241-247, 2006）。1998年日本盐鲑鱼卵引起的肠出血性大肠杆菌（EHEC） O157:H7暴发中，一株食品分离株（F2）耐盐，一株患者分离株（P5）对NaCl敏感。过氧化氢酶和NaCl一样，在P5中诱导了显著的可培养性损失。BacLight实验表明EHEC O157:H7进入了可存活但不可培养（VNC）状态。小鼠传代的F2等基因变异体对NaCl和氧化敏感，在这两种胁迫下进入不可培养状态，并可通过丙酮酸钠复苏。体内传代负向调节RpoS表达，随后的应激暴露诱导EHEC O157:H7分离株的VNA状态（Asakura H. et al ., FEMS microbial . et al .）。中国科学院学报（自然科学版）；

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).