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Ohtsuka K.,Saitama Institute of Public Health | Tanaka M.,Saitama Prefectural Meat Inspection Center | Takatori K.,Japan National Institute of Health Sciences | Hara-Kudo Y.,Japan National Institute of Health Sciences
Foodborne Pathogens and Disease | Year: 2010

Beef organ meat, such as liver, and beef are major food sources contaminated with Escherichia coli O157. This study investigated the detection method of E. coli O157 in beef liver and carcass. In an experiment with beef liver inoculated with E. coli O157, the direct plating method, plating after the immunomagnetic separation (IMS) method, and Shiga toxin (Stx)-producing E. coli detection and E. coli O157 detection loop-mediated isothermal amplification (LAMP) assays were compared for the detection of Stx-producing E. coli O157. Fifty percent and 45% of samples were positive by Stx-producing E. coli detection LAMP assay and E. coli O157 detection LAMP assay, respectively. Thirty-five percent and 10% of samples were positive by the IMS method and direct plating method, respectively. In an examination of beef swab samples, contamination frequencies with E. coli O157 were analyzed by LAMP assays and the IMS method. E. coli O157 was detected in 12 of 230 samples (5.2%). There was no sample positive for E. coli O157 isolation but negative for LAMP assays for Stx gene and O157 antigen gene. Four samples (1.7%) were positive by both LAMP assays but negative by the IMS method. The result that there was no sample positive for the O157 antigen gene, but not the Stx gene, indicated that the IMS method failed to detect E. coli O157. Twenty-nine samples (12.6%) were positive for the Stx gene but not the O157 antigen gene. The results indicated that screening of Stx gene and O157 antigen gene by LAMP assays is effective in saving time and effort to isolate E. coli O157 by the IMS method because the LAMP assay is more sensitive. This suggested that samples positive for Stx gene and O157 antigen gene should be examined by the IMS method to isolate E. coli O157. © Copyright 2010, Mary Ann Liebert, Inc.


PubMed | Toyama Institute of Health, Saitama Institute of Public Health, Japan National Institute of Public Health, Hiroshima City Institute of Public Health and 7 more.
Type: | Journal: International journal of food microbiology | Year: 2016

To establish an efficient detection method for Shiga toxin (Stx)-producing Escherichia coli (STEC) O26, O103, O111, O121, O145, and O157 in food, an interlaboratory study using all the serogroups of detection targets was firstly conducted. We employed a series of tests including enrichment, real-time PCR assays, and concentration by immunomagnetic separation, followed by plating onto selective agar media (IMS-plating methods). This study was particularly focused on the efficiencies of real-time PCR assays in detecting stx and O-antigen genes of the six serogroups and of IMS-plating methods onto selective agar media including chromogenic agar. Ground beef and radish sprouts samples were inoculated with the six STEC serogroups either at 4-6CFU/25g (low levels) or at 22-29CFU/25g (high levels). The sensitivity of stx detection in ground beef at both levels of inoculation with all six STEC serogroups was 100%. The sensitivity of stx detection was also 100% in radish sprouts at high levels of inoculation with all six STEC serogroups, and 66.7%-91.7% at low levels of inoculation. The sensitivity of detection of O-antigen genes was 100% in both ground beef and radish sprouts at high inoculation levels, while at low inoculation levels, it was 95.8%-100% in ground beef and 66.7%-91.7% in radish sprouts. The sensitivity of detection with IMS-plating was either the same or lower than those of the real-time PCR assays targeting stx and O-antigen genes. The relationship between the results of IMS-plating methods and Ct values of real-time PCR assays were firstly analyzed in detail. Ct values in most samples that tested negative in the IMS-plating method were higher than the maximum Ct values in samples that tested positive in the IMS-plating method. This study indicates that all six STEC serogroups in food contaminated with more than 29CFU/25g were detected by real-time PCR assays targeting stx and O-antigen genes and IMS-plating onto selective agar media. Therefore, screening of stx and O-antigen genes followed by isolation of STECs by IMS-plating methods may be an efficient method to detect the six STEC serogroups.


Wajima T.,Tokyo University of Pharmacy and Life Science | Morozumi M.,Keio University | Hanada S.,Toranomon Hospital | Sunaoshi K.,Saitama Institute of Public Health | And 3 more authors.
Emerging Infectious Diseases | Year: 2016

We collected β-hemolytic streptococci (1,611 isolates) from patients with invasive streptococcal infections in Japan during April 2010–March 2013. Streptococcus dysgalactiae subsp. equisimilis (SDSE) was most common (n = 693); 99%m of patients with SDSE infections were elderly (mean age 75 years, SD ±15 years). We aimed to clarify molecular and epidemiologic characteristics of SDSE isolates and features of patient infections. Bacteremia with no identified focus of origin and cellulitis were the most prevalent manifestations; otherwise, clinical manifestations resembled those of S. pyogenes infections. Clinical manifestations also differed by patient’s age. SDSE isolates were classified into 34 emm types; stG6792 was most prevalent (27.1%), followed by stG485 and stG245. Mortality rates did not differ according to emm types. Multilocus sequence typing identified 46 sequence types and 12 novel types. Types possessing macrolide-and quinolone-resistance genes were 18.4% and 2.6%, respectively; none showed blactam resistance. Among aging populations, invasive SDSE infections are an increasing risk. © 2016, Centers for Disease Control and Prevention (CDC). All rights reserved.


Takekuma M.,Saitama Institute of Public Health | Saito K.,Hoshi University | Falandysz J.,University of Gdansk | Nakazawa H.,Hoshi University
Science of the Total Environment | Year: 2011

This study investigates the compositional variations, changes in concentrations and contribution of particular congeners of PCDDs, PCDFs, non-ortho PCBs and mono-ortho PCBs in human milk from two mothers sampled during the 12-month lactation period. Total PCDD/F and dioxin-like PCB concentration in milk sampled from the primiparous mother on day 5 after delivery was 37. pg. TEQ/g fat, and this value decreased significantly by 43% at 12. months. In milk sampled from the multiparous mother nursing her second child on day 5 after delivery was 12. pg. TEQ/g fat, and this value decreased by 40% at 12. months. The decrease was statistically significant not for PCDD/Fs, but for dioxin-like PCBs. The ratio variance of the congener profiles of PCDD/Fs and dioxin-like PCBs in the milk remained similar during lactation. Moreover, the congener profiles of PCDD/Fs and dioxin-like PCBs in the milk showed similar percentages for both mothers independent of the lactation event and the number of previous births. The mean daily intake of dioxins by the infant nursed by the primiparous mother and the infant nursed by the multiparous mother up to six months of age was 140 and 46. pg TEQ/kg body weight, respectively. From seven to twelve months of age, the mean daily intake was 37 and 13. pg TEQ/kg body weight, respectively. Both values decreased by approximately 70%. The reasons why the mothers' body burden of dioxins decreased by breastfeeding and why the infants' daily intake of human milk per body weight decreased as the infant grows older consequently decreased were considered. © 2010 Elsevier B.V.


PubMed | Aomori Prefectural Public Health and Environment Center, Miyagi Prefectural Institute of Public Health and Environment, Hokkaido Institute of Public Health, Iwate Prefectural Meat Inspection Center and 8 more.
Type: | Journal: Scientific reports | Year: 2015

We studied the molecular evolution of the capsid gene in all genotypes (genotypes 1-9) of human norovirus (NoV) genogroup I. The evolutionary time scale and rate were estimated by the Bayesian Markov chain Monte Carlo (MCMC) method. We also performed selective pressure analysis and B-cell linear epitope prediction in the deduced NoV GI capsid protein. Furthermore, we analysed the effective population size of the virus using Bayesian skyline plot (BSP) analysis. A phylogenetic tree by MCMC showed that NoV GI diverged from the common ancestor of NoV GII, GIII, and GIV approximately 2,800 years ago with rapid evolution (about 10(-3) substitutions/site/year). Some positive selection sites and over 400 negative selection sites were estimated in the deduced capsid protein. Many epitopes were estimated in the deduced virus capsid proteins. An epitope of GI.1 may be associated with histo-blood group antigen binding sites (Ser377, Pro378, and Ser380). Moreover, BSP suggested that the adaptation of NoV GI strains to humans was affected by natural selection. The results suggested that NoV GI strains evolved rapidly and date back to many years ago. Additionally, the virus may have undergone locally affected natural selection in the host resulting in its adaptation to humans.


Matsushima Y.,Kawasaki City Institute for Public Health | Matsushima Y.,Yokohama City University | Ishikawa M.,Kawasaki City Institute for Public Health | Shimizu T.,Kawasaki City Institute for Public Health | And 11 more authors.
Eurosurveillance | Year: 2015

A novel GII.P17-GII.17 variant norovirus emerged as a major cause of norovirus outbreaks from December 2014 to March 2015 in Japan. Named Hu/GII/JP/2014/GII.P17-GII.17, this variant has a newly identified GII. P17 type RNA-dependent RNA polymerase, while the capsid sequence displays amino acid substitutions around histo-blood group antigen (HBGA) binding sites. Several variants caused by mutations in the capsid region have previously been observed in the GII.4 genotype. Monitoring the GII.17 variant’s geographical spread and evolution is important. © 2015, European Centre for Disease Prevention and Control (ECDC). All Rights Reserved.


Morozumi M.,Kitasato University | Wajima T.,Kitasato University | Kuwata Y.,Kitasato University | Chiba N.,Kitasato University | And 5 more authors.
Epidemiology and Infection | Year: 2014

Streptococcus agalactiae (group B streptococcus; GBS) isolates (n = 150) from infants with invasive infections between 2006 and 2011 were analysed for capsular serotype, multilocus sequence type, and antibiotic susceptibility. In cases with late-onset disease (n = 115), primary meningitis was predominant (62·6%), but represented only 39·1% in cases with early-onset disease (n = 23). The most common serotype was III (58·7%), followed by Ia (21·3%) and Ib (12·7%). Sequence types (STs) of serotype III strains included ST17 (50·0%), ST19 (26·1%), ST335 (18·2%), ST27 (4·5%), and ST1 (1·1%). Predominant STs of serotypes Ia and Ib were ST23 (81·3%) and ST10 (84·2%), respectively. No penicillin-resistant strains were detected, but 22·0% of strains had mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance. A new ST335, possessing an mef(A/E) gene belonging to clonal complex 19 gradually increased in frequency. Improved prevention of invasive GBS infections in infants requires timely identification, and ultimately vaccine development. © 2013 Cambridge University Press.


Matsuzaki K.,Nihon University | Ishii R.,Saitama Institute of Public Health | Kobiyama K.,Nihon University | Kitanaka S.,Nihon University
Journal of Natural Medicines | Year: 2010

New benzophenone and flavonol galloyl glycosides were isolated from an 80% MeOH extract of Psidium guajava L. (Myrtaceae) together with five known quercetin glycosides. The structures of the novel glycosides were elucidated to be 2,4,6-trihydroxybenzophenone 4-O-(6′-O-galloyl)-β-D- glucopyranoside (1, guavinoside A), 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6′-Ogalloyl)-β-D-glucopyranoside (2, guavinoside B), and quercetin 3-O-(5′-O-galloyl)-a-L-arabinofuranoside (3, guavinoside C) by NMR, MS, UV, and IR spectroscopies. Isolated phenolic glycosides showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage- like cell line, RAW 264.7. © The Author(s) 2010.


Jiao W.-H.,Shenyang Pharmaceutical University | Gao H.,Jinan University | Li C.-Y.,Shenyang Pharmaceutical University | Zhou G.-X.,Jinan University | And 4 more authors.
Magnetic Resonance in Chemistry | Year: 2010

Five new β-carboline alkaloids, 6,12-dimethoxy-3-(2-hydroxylethyl)- β-carboline (1), 3,10-dihydroxy-β-carboline (2), 6,12-dimethoxy-3-(1- hydroxylethyl)-β-carboline (3), 6,12-dimethoxy-3-(1,2-dihydroxylethyl)- β-carboline (4), and 6-methoxy-3-(2-hydroxyl-1-ethoxylethyl)-β- carboline (5), and two new natural products, 6-methoxy-12-hydroxy-3- methoxycarbonyl-β-carboline (6) and 3-hydroxy-β-carboline (7) were isolated from the stems of Picrasma quassioides along with 16 known β-carboline alkaloids (8-23). The structures of new compounds were determined by extensive spectroscopic analyses, and the 1D and 2D NMR data of compounds 6, 7 and 10 were reported for the first time. The bioassays showed that only compounds 14 and 16 could enhance the differentiation of 3T3-L1 preadiocytes accompanied by secretion of adiponectin proteins among these 23 compounds. Copyright © 2010 John Wiley & Sons, Ltd.


Ochiai Y.,Nippon Veterinary and Life Science University | Yamada F.,Nippon Veterinary and Life Science University | Yamada F.,Saitama Institute of Public Health | Batmunkh O.,Nippon Veterinary and Life Science University | And 4 more authors.
Journal of Food Protection | Year: 2010

This study was conducted to determine the prevalence of Listeria monocytogenes in retailed meats, comprising beef, chicken, and pork, in the Tokyo metropolitan area. A total of 379 samples of retailed meat were collected from 1998 to 2003, most of which were obtained by simultaneously purchasing the three classes of meat from a shop and then making another simultaneous purchase of meat from the same shop a few weeks later. The prevalence of L. monocytogenes was 28.0%, and the serotypes isolated were mainly 1/2a, 1/2b, 1/2c, and 4b. Comparison of the prevalence of each serotype among the classes of meat showed a predominant distribution of serotypes 1/2a, 1/2b, and 4b in chicken, while serotype 1/2c was dominant in pork. A total of nine cases considered to be due to persistence and/or cross-contamination were found. Most of the strains involved in persistence and/or cross-contamination were of serotypes 1/2c or 4b. These results suggest that contamination in retailed meat in Japan is at almost the same level as in other countries and that chicken has the highest potential as a source of contamination and infection. In addition, we suggest that the ecological niche of serotype 1/2c is distinct from those of 1/2a, 1/2b, and 4b, which may explain why human hosts have less opportunity to be exposed to serotype 1/2c and why there is a lower rate of isolation of this serotype from cases of human listeriosis. Copyright © International Association for Food Protection.

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