In order to evaluate reliability of pulsed-field gel electrophoresis (PFGE) analysis performed at different prefectural public health institutes (PHIs) for use in the PulseNet Japan surveillance system to detect enterohemorrhagic Escherichia coli O157, we compared the results of PFGE-typing of 14 selected strains of O157 performed at 8 selected PHIs to evaluate the reliability of different experimental protocols used in these PHIs. PFGE was performed for 14 strains for which there were 14 PFGE types in 3 PHIs, and 13 PFGE types in 5 PHIs by using their own protocols and/or those of the National Institute of Infectious Diseases (NIID). PFGE fingerprints from 5 out of the 8 PHIs were successfully genotyped for all of the 14 strains. A PFGE fingerprint from one PHI was successfully genotyped when the NIID pulsing protocol was used, but was not genotyped when the PHI's own protocols were used. PFGE fingerprints from 2 PHIs failed to be genotyped for one each of the strains. The cause of this genotyping failure was considered to be inappropriate PFGE pulsing protocols or inadequate digestion of chromosomal DNA. These results suggest that PFGE protocols should be standardized for the establishment of PulseNet Japan.
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Jpn J Infect Dis
January 2008
Department of Epidemiology, Public Health College, Harbin Medical University, Harbin, China.
We identified seven distinct subtypes of enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were derived from sporadic cases and outbreaks from multiple prefectures in Japan in 2005. A surveillance system utilizing pulsed-field gel electrophoresis (PFGE), PulseNet Japan, was used. Some strains showed indistinguishable PFGE patterns using another restriction enzyme (BlnI or SpeI) in each subtype of EHEC O157:H7 isolates that were routinely subtyped by the XbaI PFGE pattern.
View Article and Find Full Text PDFFoodborne Pathog Dis
June 2006
Department of Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan.
We applied pulsed-field gel electrophoresis (PFGE) to the investigation of diffuse outbreaks of illness due to Shiga toxin?producing Escherichia coli O157:H7 (STEC O157) in Japan and used these data to develop a database of STEC O157 PFGE patterns and associated clinical and microbiologic information to facilitate the recognition of geographic and temporal clusters of cases based on their PFGE profiles. This project has evolved into a subtyping network called PulseNet Japan that is cooperatively run by National Institute of Infectious Diseases (NIID) and the local Health Institutes and the Ministry of Health, Labor and Welfare. Although our domestic PFGE network that utilized locally developed PFGE protocols was effective in recognizing diffuse outbreaks of STEC O157 within Japan, we decided to adopt the standardized PFGE protocols from PulseNet USA and collaborate closely with the Centers for Disease Control and Prevention (CDC) in the United States to facilitate recognition of international clusters of STEC O157 and their investigations.
View Article and Find Full Text PDFFoodborne Pathog Dis
June 2006
Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
PulseNet is a network that utilizes standardized pulsed-field gel electrophoresis (PFGE) protocols with the purpose of conducting laboratory-based surveillance of foodborne pathogens. PulseNet standardized PFGE protocols are subject to rigorous testing during the developmental phase and careful evaluation during a validation process assessing its robustness and reproducibility in different laboratories. Here we describe the development and validation of a rapid PFGE protocol for subtyping Vibrio cholerae for use in PulseNet International activities.
View Article and Find Full Text PDFJpn J Infect Dis
June 2005
Aichi Prefectural Institute of Public Health, 7-6 Nagare, Tsuji-machi, Kita-ku, Nagoya 462-8576, Japan.
In order to evaluate reliability of pulsed-field gel electrophoresis (PFGE) analysis performed at different prefectural public health institutes (PHIs) for use in the PulseNet Japan surveillance system to detect enterohemorrhagic Escherichia coli O157, we compared the results of PFGE-typing of 14 selected strains of O157 performed at 8 selected PHIs to evaluate the reliability of different experimental protocols used in these PHIs. PFGE was performed for 14 strains for which there were 14 PFGE types in 3 PHIs, and 13 PFGE types in 5 PHIs by using their own protocols and/or those of the National Institute of Infectious Diseases (NIID). PFGE fingerprints from 5 out of the 8 PHIs were successfully genotyped for all of the 14 strains.
View Article and Find Full Text PDFKansenshogaku Zasshi
October 2002
Department of Bacteriology, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan.
As the foods are stocked below freezing and widely distributed, a kind of food-borne outbreak which occurs in separate regions or in different time, so called "diffuse outbreak", has been found at the present day. Unless the outbreak is early recognized, the number of victims would increase. Some methods have been developed to analyze the relatedness of bacteria isolated from the patients of enteric infections.
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