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Ikebe T.,Japan National Institute of Infectious Diseases | Tominaga K.,Yamaguchi Prefectural Institute of Public Health and Environment | Shima T.,Toyama Institute of Health | Okuno R.,Japan National Institute of Public Health | And 10 more authors.
Epidemiology and Infection | Year: 2015

Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multi-organ failure, and high mortality. In Japan, appropriate notification measures based on the Infectious Disease Control law are mandatory for cases of STSS caused by β-haemolytic streptococcus. STSS is mainly caused by group A streptococcus (GAS). Although an average of 60-70 cases of GAS-induced STSS are reported annually, 143 cases were recorded in 2011. To determine the reason behind this marked increase, we characterized the emm genotype of 249 GAS isolates from STSS patients in Japan from 2010 to 2012 and performed antimicrobial susceptibility testing. The predominant genotype was found to be emm1, followed by emm89, emm12, emm28, emm3, and emm90. These six genotypes constituted more than 90% of the STSS isolates. The number of emm1, emm89, emm12, and emm28 isolates increased concomitantly with the increase in the total number of STSS cases. In particular, the number of mefA-positive emm1 isolates has escalated since 2011. Thus, the increase in the incidence of STSS can be attributed to an increase in the number of cases associated with specific genotypes. Copyright © Cambridge University Press 2014. Source

Murakami K.,Fukuoka Institute of Health Environmental | Etoh Y.,Fukuoka Institute of Health Environmental | Ichihara S.,Fukuoka Institute of Health Environmental | Maeda E.,Fukuoka Institute of Health Environmental | And 6 more authors.
PLoS ONE | Year: 2014

An increasing number of Shiga toxin 2f-producing Escherichia coli (STEC2f) infections in humans are being reported in Europe, and pigeons have been suggested as a reservoir for the pathogen. In Japan, there is very little information regarding carriage of STEC2f by pigeons, prompting the need for further investigation. We collected 549 samples of pigeon droppings from 14 locations in Kyushu, Japan, to isolate STEC2f and to investigate characteristics of the isolates. Shiga toxin stx2f gene fragments were detected by PCR in 16 (2.9%) of the 549 dropping samples across four of the 14 locations. We obtained 23 STEC2f-isolates from seven of the original samples and from three pigeon dropping samples collected in an additional sampling experiment (from a total of seven locations across both sampling periods). Genotypic and phenotypic characteristics were then examined for selected isolates from each of 10 samples with pulsed-field gel electrophoresis profiles. Eight of the stx 2f gene fragments sequenced in this study were homologous to others that were identified in Europe. Some isolates also contained virulence-related genes, including lpfAO26, irp2, and fyuA, and all of the 10 selected isolates maintained the eae, astA, and cdt genes. Moreover, five of the 10 selected isolates contained sfpA, a gene that is restricted to Shiga toxin-producing E. coli O165:H2 and sorbitol-fermenting Shiga toxin-producing E. coli O157:NM. We document serotypes O152:HNM, O128:HNM, and O145:H34 as STEC2f, which agrees with previous studies on pigeons and humans. Interestingly, O119:H21 was newly described as STEC2f. O145:H34, with sequence type 722, was described in a German study in humans and was also isolated in the current study. These results revealed that Japanese zoonotic STEC2f strains harboring several virulence-related factors may be of the same clonal complexes as some European strains. These findings provide useful information for public health-related disease management strategies in Japan. © 2014 Murakami et al. Source

Ohnishi T.,Japan National Institute of Health Sciences | Lim B.,Jeju National University | Nojima N.,Center for Inspection of Imported Foods and Infectious Deseases | Kunitoshi O.,Center for Inspection of Imported Foods and Infectious Deseases | And 10 more authors.
Biocontrol Science | Year: 2016

Kudoa septempunctata is the causative agent of a food-borne disease associated with the ingestion of raw olive flounder. As the current qRT-PCR method for its detection is time-consuming, a rapid and simple method is required. Recently, a new real-time loop-mediated isothermal amplification (LAMP) method and an immunochromatography method, whose sensitivities are intended to be compatible with that designated in the official analytical method (105 spores/g olive flounder), have been developed. To validate these new methods, we performed an inter-laboratory study across seven laboratories. Both methods could not detect less than 104 spores/g; however, these methods were able to detect more than 105 spores/g in olive flounder samples. These results demonstrated that the sensitivities of these methods were compatible with the designated level in the official analytical method. We concluded that these new methods were acceptable as the screening methods for K. septempunctata. Source

Tang W.-F.,Oita University | Ogawa M.,Oita Prefectural Institute of Health and Environment | Eshita Y.,Oita University | Aono H.,Oita University | Makino Y.,Oita University
Infection, Genetics and Evolution | Year: 2010

In order to identify the patterns of genetic change of Japanese encephalitis virus (JEV) strains circulating in Oita, the complete envelope (E) gene has been sequenced for 35 isolates from swine in a 30-year span. Based on nucleotide and deduced amino acid sequences, the genetic variation was examined, phylogeny was estimated and selection pressures were also analyzed. This study demonstrated that the major genotype (G) of JEV isolates had shifted from GIII to GI in the mid-1990s in Oita. The intensities of selection acting on the Oita GIII and GI strains were found to be almost same. It suggests that the intensity of selection might not be the reason for such a genotype shift observed in Oita. Pairwise comparisons revealed the high conservation of the E gene at the protein level. Compared with the Oita GIII strains, all the Oita GI strains shared four amino acid changes at E129 (T-M), E222 (A-S), E327 (S-T) and E366 (A-S). Among all 70 JEV isolates involved in this paper, the GI strains shared only one amino acid change at E222 (A-S) in comparison with the GIII strains. No strong evidence for positive selection was found, the JEV evolution has generally been subject to strong purifying selection, but one ongoing evolutionary pathway was found to be under relaxed purifying selection in Oita. This study is a localized example of JEV molecular evolution in nature. © 2009 Elsevier B.V. All rights reserved. Source

Narimatsu H.,Oita Prefectural Institute of Health and Environment | Narimatsu H.,Oita University | Ogata K.,Oita Prefectural Institute of Health and Environment | Makino Y.,Oita University | Ito K.,Japan National Institute of Infectious Diseases
Journal of Clinical Microbiology | Year: 2010

The relationship to diarrhea of genes located on the pathogenicity islands (PAI) other than the locus of enterocyte effacement (LEE) was investigated. Enteropathogenic Escherichia coli (EPEC), the retention of espC on the EspC PAI, the OI-122 genes (efa1/lifA, nleB), the phylogenetic marker gene yjaA, and the bundle-forming pilus gene bfpA on the EPEC adherence factor (EAF) plasmid were studied. E. coli strains carrying the intimin gene (eae) without the Shiga toxin gene, isolated from patients with diarrhea (n = 83) and healthy individuals (n = 38) in Japan, were evaluated using PCR. The genotypes of eae and espC were identified by heteroduplex mobility assay (HMA). The proportions of strains isolated from individuals with and without diarrhea that carried these genes were as follows: bfpA, 13.3 and 7.9%, respectively; espC, 25.3 and 36.8%; efa1/lifA, 32.5 and 13.2%; nleB, 63.9 and 60.5%; yjaA, 42.2 and 55.3%. Statistical significance (P < 0.05) was achieved only for efa1/lifA. The proportion of strains lacking espC and carrying efa1/lifA was higher for patient-derived strains (30.1%) than for strains from healthy individuals (13.2%), but the difference was not significant. Strains carrying both espC and efa1/lifA were rare (2 strains from patients). Statistical analyses revealed significant relationships between espC and yjaA and between efa1/lifA and nleB, as well as significant inverse relationships between espC and efa1/lifA and between efa1/lifA and yjaA. espC was found in eae HMA types a1, a2, and c2, whereas efa1/lifA was found in types b1, b2, and c1. In addition, 6 polymorphisms of espC were found. The espC, yjaA, efa1/lifA, and nleB genes were mutually dependent, and their distributions were related to eae type, findings that should be considered in future epidemiological studies. Copyright © 2010, American Society for Microbiology. All Rights Reserved. Source

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