2005 Fiscal Year Final Research Report Summary
Surveillance of Bacterial Intestinal diseases in Southeast Asian countries
| Project/Area Number |
16406013
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Osaka Prefecture University (2005)
Okayama University (2004) |
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Principal Investigator |
KURAZONO Hisao Osaka Prefecture University, Dept. of Veterinary Medicine, Professor, 生命環境科学研究科, 教授 (90186487)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAYAMA Toshiya Nagasaki University, Institute for Tropical Medicine, Professor, 熱帯医学研究所, 教授 (50050696)
MAKINO Souichi Obihiro University, Center for Animal Hygiene and Food Safety, Professor, 大動物特殊疾病研究センター, 教授 (30181621)
HOSHI Hidenobu Osaka Prefecture University, Dept. of Veterinary Medicine, Research Associate, 生命環境科学研究科, 助手 (30301188)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Southeast Asia / Bacteria / Intestinal Infection / Virulence factor / Epidemiology |
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| Research Abstract |
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).
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