Fukuoka City Institute for Hygiene and the Environment

Chūō-ku, Japan

Fukuoka City Institute for Hygiene and the Environment

Chūō-ku, Japan
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Lee K.-I.,Japan National Institute of Infectious Diseases | Morita-Ishihara T.,Japan National Institute of Infectious Diseases | Iyoda S.,Japan National Institute of Infectious Diseases | Ogura Y.,Kyushu University | And 40 more authors.
Frontiers in Microbiology | Year: 2017

From 2014 to 2015, we investigated a suspected nationwide outbreak of enterohemorrhagic Escherichia coli serogroup O121. However, similar pulsed field gel electrophoresis (PFGE) profiles and the lack of epidemiological links between the isolates made detection of the outbreak difficult. To elucidate a more precise genetic distance among the isolates, whole genome sequence (WGS) analyses were implemented in the investigation. The WGS-based single nucleotide polymorphism (SNP) analysis showed that 23 out of 44 isolates formed a distinct cluster (the number of intra-cluster SNPs was ≤8). Specific genomic regions in the clustered isolates were used to develop a specific PCR analysis. The PCR analysis detected all the clustered isolates and was suitable for rapid screening during the outbreak investigation. Our results showed that WGS analyses were useful for the detection of a geographically widespread outbreak, especially for isolates showing similar PFGE profiles and for the development of a rapid and cost-effective screening method. © 2017 Lee, Morita-Ishihara, Iyoda, Ogura, Hayashi, Sekizuka, Kuroda, Ohnishi and EHEC Working Group in Japan.


Takashita E.,Japan National Institute of Infectious Diseases | Kiso M.,Tokyo Medical University | Fujisaki S.,Japan National Institute of Infectious Diseases | Yokoyama M.,Japan National Institute of Infectious Diseases | And 77 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2015

Between September 2013 and July 2014, 2,482 influenza 2009 pandemic A(H1N1) [A(H1N1)pdm09] viruses were screened in Japan for the H275Y substitution in their neuraminidase (NA) protein, which confers cross-resistance to oseltamivir and peramivir. We found that a large cluster of the H275Y mutant virus was present prior to the main influenza season in Sapporo/Hokkaido, with the detection rate for this mutant virus reaching 29% in this area. Phylogenetic analysis suggested the clonal expansion of a single mutant virus in Sapporo/Hokkaido. To understand the reason for this large cluster, we examined the in vitro and in vivo properties of the mutant virus. We found that it grew well in cell culture, with growth comparable to that of the wild-type virus. The cluster virus also replicated well in the upper respiratory tract of ferrets and was transmitted efficiently between ferrets by way of respiratory droplets. Almost all recently circulating A(H1N1)pdm09 viruses, including the cluster virus, possessed two substitutions in NA, V241I and N369K, which are known to increase replication and transmission fitness. A structural analysis of NA predicted that a third substitution (N386K) in the NA of the cluster virus destabilized the mutant NA structure in the presence of the V241I and N369K substitutions. Our results suggest that the cluster virus retained viral fitness to spread among humans and, accordingly, caused the large cluster in Sapporo/Hokkaido. However, the mutant NA structure was less stable than that of the wild-type virus. Therefore, once the wild-type virus began to circulate in the community, the mutant virus could not compete and faded out. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


Kishida N.,Japan National Institute of Infectious Diseases | Fujisaki S.,Japan National Institute of Infectious Diseases | Yokoyama M.,Japan National Institute of Infectious Diseases | Sato H.,Japan National Institute of Infectious Diseases | And 18 more authors.
Clinical and Vaccine Immunology | Year: 2012

The vaccine strains against influenza virus A/H3N2 for the 2010-2011 season and influenza virus B for the 2009-2010 and 2010-2011 seasons in Japan are a high-growth reassortant A/Victoria/210/2009 (X-187) strain and an egg-adapted B/Brisbane/60/2008 (Victoria lineage) strain, respectively. Hemagglutination inhibition (HI) tests with postinfection ferret antisera indicated that the antisera raised against the X-187 and egg-adapted B/Brisbane/60/2008 vaccine production strains poorly inhibited recent epidemic isolates of MDCK-grown A/H3N2 and B/Victoria lineage viruses, respectively. The low reactivity of the ferret antisera may be attributable to changes in the hemagglutinin (HA) protein of production strains during egg adaptation. To evaluate the efficacy of A/H3N2 and B vaccines, the cross-reactivities of postvaccination human serum antibodies against A/H3N2 and B/Victoria lineage epidemic isolates were assessed by a comparison of the geometric mean titers (GMTs) of HI and neutralization (NT) tests. Serum antibodies elicited by the X-187 vaccine had low cross-reactivity to both MDCK-and egg-grown A/H3N2 isolates by HI test and narrow cross-reactivity by NT test in all age groups. On the other hand, the GMTs to B viruses detected by HI test were below the marginal level, so the cross-reactivity was assessed by NT test. The serum neutralizing antibodies elicited by the B/Brisbane/60/2008 vaccine reacted well with egg-grown B viruses but exhibited remarkably low reactivity to MDCK-grown B viruses. The results of these human serological studies suggest that the influenza A/H3N2 vaccine for the 2010-2011 season and B vaccine for the 2009-2010 and 2010-2011 seasons may possess insufficient efficacy and low efficacy, respectively. Copyright © 2012, American Society for Microbiology. All Rights Reserved.


PubMed | Oita Prefectural Institute of Health and Environment, Kumamoto Prefectural Meat Inspection Office, University of Miyazaki, Toyama Institute of Health and 13 more.
Type: Journal Article | Journal: Open forum infectious diseases | Year: 2015

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection causes severe diseases such as bloody diarrhea and hemolytic uremic syndrome (HUS). Although EHEC O157:H7 strains have exhibited high genetic variability, their abilities to cause human diseases have not been fully examined.Clade typing and stx subtyping of EHEC O157:H7 strains, which were isolated in Japan during 1999-2011 from 269 HUS patients and 387 asymptomatic carriers (ACs) and showed distinct pulsed-field gel electrophoresis patterns, were performed to determine relationships between specific lineages and clinical presentation.Clades 6 and 8 strains were more frequently found among the isolates from HUS cases than those from ACs (P = .00062 for clade 6, P < .0001 for clade 8). All clade 6 strains isolated from HUS patients harbored stx2a and/or stx2c, whereas all clade 8 strains harbored either stx2a or stx2a/stx2c. However, clade 7 strains were predominantly found among the AC isolates but less frequently found among the HUS isolates, suggesting a significant association between clade 7 and AC (P < .0001). Logistic regression analysis revealed that 0-9 year old age is a significant predictor of the association between clade 8 and HUS. We also found an intact norV gene, which encodes for a nitric oxide reductase that inhibits Shiga toxin activity under anaerobic condition, in all clades 1-3 isolates but not in clades 4-8 isolates.Early detection of EHEC O157:H7 strains that belonged to clades 6/8 and harbored specific stx subtypes may be important for defining the risk of disease progression in EHEC-infected 0- to 9-year-old children.


Tsuruda S.,Fukuoka City Institute for Hygiene and the Environment | Akaki K.,Fukuoka City Institute for Hygiene and the Environment | Hiwaki H.,Fukuoka City Institute for Hygiene and the Environment | Suzuki A.,Chiba University | Akiyama H.,Japan National Institute of Health Sciences
Bioscience, Biotechnology and Biochemistry | Year: 2012

A rapid multiplex real-time PCR assay was developed to achieve highly specific, simultaneous detection of two kinds of mushrooms, Omphalotus guepiniformis and Lentinula edodes. Primers and TaqMan minor groove binder probes were designed according to the internal transcribed spacers 1-5.8S region of rDNA and evaluated by the specificity for fruiting bodies of 17 O. guepiniformis, 16 L. edodes and samples from 57 other species. DNA extracts of all the target species had positive signals with no cross-reaction, the limit of detection being 0.00025 ng of DNA. Threshold cycle (Ct) values for raw and processed fruiting bodies and for fruiting bodies (1% (w/w)) mixed with foodstuffs or artificial gastric juice contents ranged from 17.16 to 26.60 for both examined species. This new assay proved specific to the target species, highly sensitive, and applicable to processed food samples and gastric juice contents, making it useful for rapidly identifying O. guepiniformis and L. edodes.


Watanabe T.,Japan National Institute of Health Sciences | Kikuchi H.,Japan National Institute of Health Sciences | Matsuda R.,Japan National Institute of Health Sciences | Hayashi T.,Japan National Institute of Health Sciences | And 2 more authors.
Journal of the Food Hygienic Society of Japan | Year: 2015

Here, we set out to improve our previously developed methylmercury analytical method, involving phenyl derivatization and gas chromatography-mass spectrometry (GC-MS). In the improved method, phenylation of methylmercury with sodium tetraphenylborate was carried out in a toluene/ water two-phase system, instead of in water alone. The modification enabled derivatization at optimum pH, and the formation of by-products was dramatically reduced. In addition, adsorption of methyl phenyl mercury in the GC system was suppressed by co-injection of PEG200, enabling continuous analysis without loss of sensitivity. The performance of the improved analytical method was independently evaluated by three analysts using certified reference materials and methylmercury- spiked fresh fish samples. The present analytical method was validated as suitable for determination of compliance with the provisional regulation value for methylmercury in fish, set in the Food Sanitation haw.


Sakamoto T.,Fukuoka City Institute for Hygiene and the Environment | Akaki K.,Fukuoka City Institute for Hygiene and the Environment | Watanabe T.,Japan National Institute of Health Sciences | Matsuda R.,Japan National Institute of Health Sciences | Hiwaki H.,Fukuoka City Institute for Hygiene and the Environment
Bunseki Kagaku | Year: 2012

A method for the determination of methylmercury in foods by GC-MS method following phenylation was investigated. Methylmercury was isolated by acid leaching (mixture of potassium bromide solution and sulfuric acid saturated with copper sulfate), the extraction of methylmercury into toluene, then back-extraction into L-cysteine solution. Methylmercury was phenylated with sodium tetraphenylborate, and extracted into n-heptane. Phenylated methylmercury was purified by PSA mini-column, then analyzed by GC-MS (SIM). As a result of the performance evaluation using five certified reference materials (CRM-7402a, CRM-7403a, BCR-463, ERMCE-464 and DOLT-4), trueness (%), repeatability (RSD%) and reproducibility within laboratory (RSD%) was 98-108, less than 10 and less than 15, respectively. It was shown that the method satisfy the performance satisfied criteria set by Ministry of Health, Labor and Welfare. © 2012 The Japan Society for Analytical Chemistry.

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