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Purpose: To evaluate the diagnostic performance of noncontrast-enhanced magnetic resonance imaging (MRI) to grade pancreatic fibrosis and to assess hemoglobin (Hb) A1c values. Materials and Methods: Twenty-nine consecutive patients with pancreatic or biliary malignancy who underwent pancreatectomy were evaluated. Patients were classified into three groups: HbA1c < 5.7 (group 1), 5.7 ≤ HbA1c < 6.5 (group 2), and HbA1c ≥ 6.5 (group 3). MRI of the pancreas was performed using a 1.5T MR system. The pancreas-to-muscle signal intensity ratio (SIR) on in- and opposed-phase T1 -, T2 -, and diffusion-weighted images, as well as the apparent diffusion coefficient were calculated. MRI measurements, degrees of pancreatic fibrosis, and HbA1c values were compared using multiple regression analysis and Kruskal-Wallis test. Results: The pancreatic fibrosis grade was negatively correlated with the SIR on in-phase T1 -weighted images (r = -0.67, P = 0.0002). The pancreatic fibrosis grade and HbA1c value were negatively correlated with the SIR on opposed-phase T1 -weighted images (r = -0.47, P = 0.019 and r = -0.51, P = 0.0089, respectively). SIRs on in- and opposed-phase T1 -weighted images were significantly lower in group 3 than in groups 1 and 2 (P < 0.05). Conclusion: The pancreas-to-muscle SIRs on in- and opposed-phase T1 -weighted images could be a potential biomarker for pancreatic fibrosis and elevated HbA1c values. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the feasibility of diffusion kurtosis (DK) imaging of the pancreas for the assessment of hemoglobin (Hb) A1c values.Materials and Methods: Our Institutional Review Board approved this prospective study and written informed consent was obtained. In all, 102 consecutive patients with suspected pancreatic disease underwent magnetic resonance imaging (MRI), including DK imaging. Patients were classified into three groups according to American Diabetes Association criteria: HbA1c < 5.7% (group 1), 5.7% ≤ HbA1c < 6.5% (group 2), and HbA1c ≥ 6.5% (group 3). Mean kurtosis (MK) and apparent diffusion coefficient (ADC) of pancreatic parenchyma were computed. MRI measurements and HbA1c values were then compared.Results: HbA1c values positively correlated with MK (r = 0.66, P < 0.0001). Group 3 was significantly (P < 0.05) higher (P < 0.05) in MK than groups 1 and 2. The sensitivity, specificity, and area under the ROC curve of the MK for the detection of group 3 were 90%, 88%, and 0.92, respectively.Conclusion: The MK measurement on DK imaging of the pancreas could be a potential biomarker for assessing HbA1c level. [ABSTRACT FROM AUTHOR]

In Vibrio cholerae, 41 chitin-inducible genes, including the genes involved in natural competence for DNA uptake, are governed by the orphan two-component system ( TCS) sensor kinase ChiS. However, the mechanism by which ChiS controls the expression of these genes is currently unknown. Here, we report the involvement of a novel transcription factor termed ' TfoS' in this process. TfoS is a transmembrane protein that contains a large periplasmic domain and a cytoplasmic AraC-type DNA-binding domain, but lacks TCS signature domains. Inactivation of tfoS abolished natural competence as well as transcription of the tfoR gene encoding a chitin-induced small RNA essential for competence gene expression. A TfoS fragment containing the DNA-binding domain specifically bound to and activated transcription from the tfoR promoter. Intracellular TfoS levels were unaffected by disruption of chiS and coexpression of TfoS and ChiS in Escherichia coli recovered transcription of the chromosomally integrated tfoR:: lacZ gene, suggesting that TfoS is post-translationally modulated by ChiS during transcriptional activation; however, this regulation persisted when the canonical phosphorelay residues of ChiS were mutated. The results presented here suggest that ChiS operates a chitin-induced non-canonical signal transduction cascade through TfoS, leading to transcriptional activation of tfoR. [ABSTRACT FROM AUTHOR]

ABSTRACT Twelve Vibrio cholerae isolates with genes for a type III secretion system (T3SS) were detected among 110 environmental and 14 clinical isolates. T3SS-related genes were distributed among the various serogroups and pulsed-field gel electrophoresis of NotI-digested genomes showed genetic diversity in these strains. However, the restriction fragment length polymorphism profiles of the T3SS-related genes had similar patterns. Additionally, naturally competent T3SS-negative V. cholerae incorporated the ca. 47 kb gene cluster of T3SS, which had been integrated into a site on the chromosome by recombination. Therefore, it is suggested that horizontal gene transfer of T3SS-related genes occurs among V. cholerae in natural ecosystems. [ABSTRACT FROM AUTHOR]

Summary The genus Borrelia is arthropod-borne infectious agents in vertebrates, and is classified into Lyme disease (LD) Borrelia spp. and Relapsing fever (RF) Borrelia spp. In addition to these Borrelia groups, we recently reported reptile-associated (REP) Borrelia spp. from reptiles and from hard-bodied ticks, which probably transmitted the REP Borrelia spp. In this study, we investigated the presence of REP Borrelia sp. in moulted ticks, and found that trans-stadial transmission of REP Borrelia sp. occurred in the midgut, while it was observed that REP Borrelia sp. entered the salivary gland during blood-feeding. This characteristic is also found in LD Borrelia spp., which are also transmitted by hard-bodied ticks. Although phylogenetic analysis demonstrated that REP Borrelia spp. are similar to RF Borrelia spp., the ecology of the spirochaetes within the vector ticks is different for REP Borrelia spp. and RF Borrelia spp. Elucidation of the evolutionary history of the genus Borrelia and its adaptation to ticks promises to be of great interest to researchers of vector-borne microorganisms. [ABSTRACT FROM AUTHOR]

The expression of the type III secretion system-a main determinant of virulence in Shigella-is controlled by regulator cascades VirF-InvE (VirB) and CpxAR two-component system. A screen for mutants that restore virulence in the cpxA background led to the isolation of a mutant of rodZ, a cytoskeletal protein that maintains the rod-shaped morphology of bacilli. InvE is normally repressed at 30 °C because of decreased messenger RNA (mRNA) stability, but rodZ mutants markedly increase invE-mRNA stability. Importantly, the inhibition of InvE production by RodZ can be genetically separated from its role in cell-shape maintenance, indicating that these functions are distinguishable. Thus, we propose that RodZ is a new membrane-bound RNA-binding protein that provides a scaffold for post-transcriptional regulation. [ABSTRACT FROM AUTHOR]

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC), a food- and waterborne pathogen, causes diarrhea, hemorrhagic colitis, and life-threatening HUS. MLVA is a newly developed and widely accepted genotyping tool. An MLVA system for EHEC O157 involving nine genomic loci has already been established. However, the present study revealed that the above-mentioned MLVA system cannot analyze EHEC O26 and O111 isolates-the second and third most dominant EHEC serogroups in Japan, respectively. Therefore, with several modifications to the O157 system and the use of nine additional loci, we developed an expanded MLVA system applicable to EHEC O26, O111, and O157. Our MLVA system had a relatively high resolution power for each of the three serogroups: Simpson's index of diversity was 0.991 (95% CI = 0.989-0.993), 0.988 (95% CI, 0.986-0.990), and 0.986 (95% CI, 0.979-0.993) for O26, O111, and O157, respectively. This system also detected outbreak-related isolates; the isolates collected during each of the 12 O26 and O111 outbreaks formed unique clusters, and most of the repeat copy numbers among the isolates collected during the same outbreak exhibited no or single-locus variations. These results were comparable to those of cluster analyses based on PFGE profiles. Therefore, our system can complement PFGE analysis-the current golden method. Because EHEC strains of three major serogroups can be rapidly analyzed on a single platform with our expanded MLVA system, this system could be widely used in molecular epidemiological studies of EHEC infections. [ABSTRACT FROM AUTHOR]

Purpose: To compare 11C-choline positron emission tomography (C-PET), 18F-fluorodeoxyglucose PET (FDG-PET), and MR imaging in the preoperative detection of prostate cancer. Materials and Methods: C-PET, FDG-PET, and MR images were obtained in 43 consecutive patients with suspected prostate cancer, and prostate cancers were histopathologically confirmed in 26 patients. Unenhanced T1-weighted, T2-weighted, and gadolinium-enhanced MR images were obtained. C-PET and FDG-PET were conducted 1.5 and 60 minutes after injection of 5.5 and 5.0 MBq/kg tracers, respectively. A nuclear and a genitourinary radiologist retrospectively reviewed PET and MR images at random, respectively, and assigned a confidence level for the presence of prostate cancer using a four-point scale. Diagnostic performance was tested using the McNemar test and receiver operating characteristic curve analysis. Results: The sensitivity was greater ( P < 0.05) with MR (88%) and C-PET (73%) images than with FDG-PET images (31%). The accuracy was greater ( P < 0.05) with MR images (88%) than with C-PET (67%) and FDG-PET (53%) images. The area-under-curve value with MR (0.90) was greater than those with C-PET (0.53) and FDG-PET (0.54) images ( P < 0.01). Conclusion: MR imaging should be primarily performed in the preoperative detection of prostate cancer. C-PET and FDG-PET did not improve the detection. J. Magn. Reson. Imaging 2010;31:1151-1156. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The members of the genus Borrelia are transmitted by arthropods and known to be infectious to vertebrates. Here we found isolates and DNAs belonging to the Borrelia turcica and unknown Borrelia species from imported reptiles and their ectoparasites. The Borrelia strains were isolated from blood and multiple organs of exotic tortoises, and were experimentally infectious to captive-bred tortoises. These findings suggest that these tortoises may be a candidate as the reservoir host of the Borrelia species. In this study, the Borrelia strains were also isolated from and/or detected in hard-bodied ticks, Amblyomma ticks and Hyalomma ticks. In some of these ticks, immunofluorescence imaging analysis revealed that the Borrelia had also invaded into the tick salivary glands. Accordingly, these ticks were expected to be a potential vector of the Borrelia species. Sequencing analyses of both housekeeping genes ( flaB gene, gyrB gene and 16S rDNA gene) and 23S rRNA gene-16S rRNA gene intergenic spacer region revealed that these Borrelia strains formed a monophyletic group that was independent from two other Borrelia groups, Lyme disease Borrelia and relapsing fever Borrelia. From these results, the novel group of Borrelia comprises the third major group of arthropod-transmitted borreliae identified to date. [ABSTRACT FROM AUTHOR]

Genes essential for eliciting pathogenicity of enterohemorrhagic Escherichia coli are located within the locus of enterocyte effacement (LEE). Expression of LEE genes is positively regulated by paralogues PchA, PchB and PchC, which are encoded by separate loci of the chromosome. To elucidate the underlying regulatory mechanism, we screened transposon mutants exhibiting reduced expression of pchA, transcription level of which is highest among the pch genes. Here, we report that the LysR-homologue A (LrhA) positively regulated the transcription of pchA and pchB. A deletion in lrhA reduced the transcription levels of pchA and pchB to different degrees, and also reduced the expression of LEE-coded type 3-secreted protein, EspB. Expression of LrhA from a plasmid restored and markedly increased the transcription levels of pchA and pchB respectively, and highly induced EspB expression. Deletion analysis of the regulatory region showed that both promoter-proximal (−195 to +88) and promoter-distal (−418 to −392 for pchA and −391 to −375 for pchB) sequences were required for the LrhA-mediated upregulation of pchA and pchB genes. Purified His6-LrhA protein differentially bound to the regulatory regions of pchA/B, suggesting that direct regulation of pchA and pchB genes by LrhA in turn controls the expression of LEE genes. [ABSTRACT FROM AUTHOR]

Objective: Measurement of salivary IgA antibody (PAc-peptide antibody, PPA) to amino acid residues 361–386 of Streptococcus mutans PAc, which possess a multiple binding motif to various HLA-DR molecules and a B-cell epitope that recognises the inhibiting antibody to S. mutans, is an indicator for the population numbers of mutans streptococci (MS) in human saliva. The purpose of this study was to clarify the role of PPA in infection control of MS after professional oral hygiene care. Materials and methods: Thirty-nine dependently living institutionalised elderly subjects (75.9 ± 7.5 years; 10 males, 29 females) participated in the study. The measurements of PPA, MS, total streptococci (TS) and lactobacilli (LB) were performed by ELISA and culture techniques from saliva, plaque and tongue samples from the elderly. Results: After treatment using professional oral care, the numbers of MS decreased significantly at 6 months in saliva and tongue samples from the group not having PPA in comparison with the primary data; whereas in the PPA-detected group, a significant decrease in MS number was shown immediately following professional care at 1–12 months in all samples. There was little difference in the numbers of LB at any of the time points. The numbers of TS decreased rapidly in PPA-not detected group in comparison with the PPA-detected group. Conclusion: PPA may be more effective for controlling MS number in the oral cavity after professional treatment. The measurement of PPA may be used for preventive instruction to dental caries at the chair side in the clinical setting. [ABSTRACT FROM AUTHOR]

A recombinant positive control plasmid was developed to be used in PCR for Orientia tsutsugamushi. This pUC19-based plasmid contains the O. tsutsugamushi DNA sequence, part of which is replaced with Candida albicans DNA. pUC19-Posi is a PCR control that provides several advantages over currently used positive controls for both universal and serotypical PCR. [ABSTRACT FROM AUTHOR]

Ehrlichia-specific DNA fragments of Ehrlichia omp-1 and groEL genes were found in two I. granulatus ticks which had been collected from wild small mammals in a subtropical zone in Japan. The DNA sequences of groEL and 16SrDNA of the suspected Ehrlichia were clustered into a group of E. chaffeensis, E. muris, and Ehrlichia sp. HF565 found in I. ovatus, but were distinctly different. Therefore the Ehrlichia strain was designated as a novel Ehrlichia sp. 360. The Ehrlichia sp. 360 was detected in I. granulatus but not in any other ticks. This suggests that I. granulatus is a probable vector of Ehrlichia sp. 360 in Japan. [ABSTRACT FROM AUTHOR]

Purpose To determine the optimal b values required for diffusion-weighted (DW) imaging of the liver in the detection and characterization of benign and malignant hepatic lesions. Materials and Methods MR images obtained in 76 patients including 28 malignant hepatic lesions (21 hepatocellular carcinomas and 7 metastases) and 27 benign lesions (12 hemangiomas and 15 cysts) were reviewed. DW-echo planner images (EPIs; b values with100, 200, 400, and 800 s/mm2) were reviewed solely first, and then with T2-weighted EPIs ( b = 0 s/mm2). Results Sensitivity for malignant lesions (74%) was highest on DW-EPIs with b value of 100 s/mm2 and T2-weighted EPIs combined ( P < 0.05), and sensitivity for benign lesions (87%) was highest on DW-EPIs with b value of 800 s/mm2 and T2-weighted EPIs ( P < 0.05). Specificities were comparably high for all sequences. The Az values for malignant lesions were 0.94, 0.90, 0.87, and 0.89, and those for benign lesions were 0.91, 0.89, 0.87, and 0.94 on DW-EPIs with b values of 100, 200, 400, and 800 and T2-weighted EPIs combined, respectively. Hepatic cysts were clearly distinguished with the cutoff ADC value of 2.5 ×10−3 mm2/s using a b value of 400 s/mm2 or greater. Conclusion DW-EPIs with middle b values were not required in the detection and characterization of benign and malignant hepatic lesions. J. Magn. Reson. Imaging 2008;28:691-697. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

To investigate the genetic difference of Legionella pneumophila in human-made environments, we collected isolates of L. pneumophila from bath water ( n = 167) and cooling tower water ( n = 128) primarily in the Kanto region in 2001 and 2005. The environmental isolates were serogrouped and sequenced for a target region of flaA. A total of 14 types of flaA genotypes were found: 10 from cooling tower water and nine from bath water. The flaA genotypes of isolates from cooling tower water were quite different from those of bath water. [ABSTRACT FROM AUTHOR]

A mismatch amplification mutation PCR assay was developed and validated for rapid detection of the biotype specific cholera toxin B subunit of V. cholerae O1. This assay will enable easy monitoring of the spread of a new emerging variant of the El Tor biotype of V. cholerae O1. [ABSTRACT FROM AUTHOR]

Pandemic V. parahaemolyticus strains have rapidly changed their serotypes, but its determinants, especially K antigen, and the genes involved in serotype have been an open question. The purpose of this study was to gain insights into these points. Although V. parahaemolyticus is known to be lacking O-side chain on its lipopolysaccharide, and O antigens are thought to be represented by core OS, the genome sequence of V. parahaemolyticus O3:K6 strain RIMD2210633 suggests that this bacterium potentially synthesizes O-side chain. To explore possible relatedness between this O-side chain biosynthesis gene cluster, which is similar in the serotypes of Vibrio cholerae, and of V. parahaemolyticus, we amplified both core OS and O-side chain gene clusters of the strains belonging to various serotypes of V. parahaemolyticus by long PCR and performed PCR RFLP analyses. The results of our RFLP analyses suggest that the core OS biosynthesis gene cluster is related to the O antigens of pandemic V. parahaemolyticus and that the putative O-side chain gene cluster is related to K antigens of pandemic V. parahaemolyticus. We then determined the sequence of these regions of a pandemic O4:K68 strain, and compared it with the corresponding sequence of RIMD2210633. In addition, PCR analysis showed the putative O4 and K68 antigen gene clusters are unique to the strains belonging to the O4 and K68 serotype respectively. The data implies that the pandemic O4:K68 V. parahaemolyticus strain emerged from the pandemic O3:K6 strain by replacement of the putative O and K antigen gene clusters. [ABSTRACT FROM AUTHOR]

Sporadic cases of hepatitis E have been reported in industrialized countries, including Japan. The source of hepatitis E virus (HEV) in these patients is unknown, although zoonotic transmission has been suggested. To investigate whether or not rodents might be a reservoir of HEV, we conducted an epidemiological survey for the antibody to a recombinant capsid protein of HEV using serum samples from wild rodents in Japan. One hundred and fourteen of 362 (31.5%) Norway rats (Rattus norvegicus) and 12 of 90 (13.3%) black rats (Rattus rattus) were positive for anti-HEV IgG. In contrast, all of the sera from 55 mice were negative for anti-HEV IgG. The rate of antibody positivity increased with weight among Norway rats. Seropositive rats were found in all five districts surveyed in this study, but the prevalence of anti-HEV IgG in wild rats differed among these prefectures. Despite the fact that Japan is a non-endemic country of hepatitis E, widespread infection of HEV was observed among wild rats in Japan. Our results suggested that HEV or a closely related virus is circulating among wild rats in Japan. [Copyright &y& Elsevier]

Background Lyme borreliosis has been implicated in the pathogenesis of acute peripheral facial palsy (APFP). Few studies, however, have used Western blot analyses to confirm the serological diagnosis. Purpose To analyze the prevalence of anti- Borrelia antibodies in patients with APFP compared with healthy control subjects living in Hokkaido Island, Japan. Patients and Methods In total, 113 patients with APFP were analyzed. They included 32 patients with varicella zoster virus (VZV) reactivation (Ramsay Hunt syndrome and zoster sine herpete) and 81 patients with Bell's palsy. Fifty-eight healthy control subjects were also included. IgM and IgG antibodies to Borrelia garinii and afzelii were tested by Western blot, and diagnoses were made according to the Centers for Disease Control and Prevention criteria. Results Five of 81 (6.2%) patients with Bell's palsy, 1 of 32 (3.1%) patients with VZV reactivation, and 1 of 58 control subjects (1.7%) were judged to have both IgM and IgG antibodies to Borrelia. This difference was not significant ( P >.05, χ2 test). Patients with Bell's palsy who had herpes simplex virus type 1 (HSV-1) reactivation at the onset of palsy had a higher IgM-immunoreactivity to Borrelia afzelii. Conclusions Although it is one of the endemic areas of Lyme disease in Japan, the prevalence of APFP caused by Lyme borreliosis is low in Hokkaido Island. In addition, cross-reactivity to B. afzelii in IgM blots is often observed in patients with HSV-1 reactivation, suggesting that careful interpretation of Borrelia IgM immunoblot data are needed for accurate serological diagnosis. [ABSTRACT FROM AUTHOR]

Summarizes the molecular epidemiological analysis of enterohemorrhagic Escherichia coli (EHEC) isolates in Japan. Symptoms experienced by patients with EHEC infection; Serotype strains whose isolation frequency is increasing.

Yersinia enterocolitica produces heat-stable enterotoxin (Y-ST) as one of its virulence factors. The yst gene, however, frequently and spontaneously becomes inactive (silent) during storage, which is accompanied by concurrent changes in some biological properties such as colony morphology, growth rate, carbon fermentation and ornithine decarboxylase activity. Northern blot analysis revealed that the level of mRNA for yst was repressed. To investigate the regulatory region, we transformed a yst-silent strain with a chromosomal gene library of Y-ST producing an isogenic counterpart. Out of 3604 clones, one clone resumed the Y-ST production and concurrently other biological properties. An open reading frame in this clone was designated as yrp, yersinia regulator for pleiotropic phenotype. Deduced from the nucleotide sequence, Yrp was a small protein of 101 amino acids with no similarity with any regulatory factor described, but showed high homology with an Escherichia coli host factor 1 required for Qβ-replicase, and with an Azorhizobium caulinodans NrfA required for the expression of nifA. The yrp gene mutation caused decreased negative supercoiling of plasmids, as did hfq. The yrp gene could similarly complement Y-ST production in two other silent strains of Y. enterocolitica. In all three silent strains examined, we found various mutations in the yrp region. [ABSTRACT FROM AUTHOR]

An approximately 1.1 kbp fragment that was commonly observed only in the enterohemorrhagic Escherichia coli (EHEC) O157 strains in an analysis of amplified fragment length polymorphism was found to be a partial gene sequence encoding the locus of toxB and a useful molecular marker for the identification of EHEC O157.

Pathogenic Escherichia coli remains important etiological agent of infantile diarrhea in Bangladesh. Previous studies have focused mostly on clinical strains, but very little is known about their presence in aquatic environments. The present study was designed to characterize potentially pathogenic E. coli isolated between November 2001 and December 2003 from aquatic environments of 13 districts of Bangladesh. Serotyping of 96 randomly selected strains revealed O161 to be the predominant serotype (19%), followed by O55 and O44 (12% each), and 11% untypable. Serotype-based pathotyping of the E. coli strains revealed 47%, 30%, and 6% to belong to EPEC, ETEC, and EHEC pathotypes, respectively. The majority of the 160 strains tested were resistant to commonly used antimicrobial agents. Plasmid pro-filing showed a total of 17 different bands ranging from 1.3 to 40 kb. However, 35% of the strains did not contain any detectable plasmid, implying no correlation between plasmid and drug resistance. Although virulence gene profiling revealed 97 (61%) of the strains to harbor the gene encoding heat-stable enterotoxin (ST), 2 for the gene encoding Shiga toxin (Stx), and none for the gene for heat-labile enterotoxin (LT), serotype-based pathotyping of E. coli was not fully supported by this gene profiling. A dendrogram derived from the PFGE patterns of 22 strains of three predominant serogroups indicated two major clusters, one containing mainly serogroup O55 and the other O8. Three strains of identical PFGE profiles belonging to serogroup O55 were isolated from three distinct areas, which may be of epidemiological significance. Finally, it may be concluded that serotype-based pathotyping may be useful for E. coli strains of clinical origin; however, it is not precise enough for reliably identifying environmental strains as diarrheagenic.

In 2003, a Leptospira survey was performed on Yoroshima Island of the Amami Islands located in the southwestern part of Japan. Seven Leptospira strains were isolated from the field rat Rattus rattus, which were identified as L. borgpetersenii by flaB sequencing, 16S rDNA sequencing and gyrB sequencing, and serovar Javanica was determined by a microscopic agglutination test. NotI-long restriction fragment analysis indicated that these isolates were genetically indistinguishable from an isolate from the Okinawa Islands. The present results suggest that L. borgpetersenii is migrating into the Amami Islands in Japan.

A real-time PCR assay with the cycling probe method was used to detect mutations at codons 83 and 87 in the DNA gyrase A subunit encoded by gyrA in Salmonella enterica serovar Typhi and Paratyphi A clinical isolates. The susceptibility estimated from the results of the gyrA mutation assay was consistent with that identified by the culture method using an E-test. This assay allows rapid screening of S. enterica serovar Typhi and Paratyphi A with reduced susceptibility to ciprofloxacin.

Rickettsia was first detected in seabird soft-bodied ticks, Carios capensis and C. sawaii in Japan. According to sequence analysis, Rickettsia in Japan was identical to Rickettsia scc31 in C. capensis in the U.S.A. This suggested that an environmental circulation had consisted among microorganisms, ticks and long distance migratory seabirds around the Pacific Ocean.

Thirty-one epidemiologically unrelated Legionella pneumophila serogroup 1 isolates (10 from cooling towers, 10 from public spas and/or hot spring baths, and 11 from patients) were analyzed by pulsed-field gel electrophoresis (PFGE) and sequence-based typing (SBT) using 6 loci, flaA, pilE, asd, mip, mompS, and proA. The results of PFGE and SBT analysis indicated that all 10 isolates from cooling towers clustered into a unique type, which was distinct from strains of other environmental sources.

DNase B is a major nuclease and a possible virulence factor in Streptococcus pyogenes. The allelic diversity of streptococcal DNase B (sdaB) gene was investigated in 83 strains with 14 emm genotypes. Of the 15 alleles identified, 11 alleles carried only synonymous nucleotide substitutions. On the other hand, 4 alleles had a non-synonymous substitution other than synonymous substitutions, resulting in the substitution of a single amino acid. The distribution of each allele was generally emm genotype-specific. Only sdaB7 was found in both emm2 and emm4. The promoter region was highly conserved and DNase B protein was similarly expressed in all alleles.

A PCR-based assay to identify pandemic group Vibrio parahaemolyticus has been developed. The assay employs an oligonucleotide primer pair derived from the group-specific sequence of an arbitrarily primed-PCR fragment, which is located in the genome encoding a "hypothetical protein," approximately 80% homologous to the Mn2+ and Fe2+ transporter of the NRAMP family of V. vulnificus. The assay distinguished the pandemic group from other V. parahaemolyticus strains by yielding a 235-bp specific amplicon, and can be a useful diagnostic tool for identification of pandemic group strains.

Clinical isolates of Streptococcus pyogenes were classified by serological typing of their surface M protein. Non-M typeable strains with the emm1 gene were characterized as the degradation of M protein caused by overproduction of the extracellular cysteine protease, SpeB. These events are dependent on the growth phase. M protein produced prior to expression of SpeB is degraded in the stationary phase when the active form of SpeB is detected. The proteolytic degradation of M protein should be considered for precise M typing analysis.

Among roughly one thousand incidents of shigellosis annually in Japan, approximately 70% of the cases are estimated to be associated with overseas travel. However, at the end of 2001, reports of domestically acquired Shigella sonnei infections suddenly increased. We report here the first multi-prefectural outbreak of Shigella sonnei infections linked to the consumption of imported oysters in Japan at the end of 2001. Isolates of S. sonnei from patients epidemiologically linked to eating contaminated oysters and from the imported oysters themselves showed an indistinguishable pulsed-field gel electrophoresis pattern and drug resistance pattern.

In the course of nationwide investigation on epidemiological characteristics in Salmonella Typhimurium isolates from food-producing animals in Japan between 1999 and 2001, fifty-seven isolates of S. Typhimurium DT104 and 104B obtained from cattle and swine at farm level in Japan between 1999 and 2001 were classified with pulsotype and antimicrobial resistance type. Most of the isolates were resistant to five or more antimicrobials and were genotyped into four groups. The present nationwide investigation shows that at least 11 types of S. Typhimurium related to DT104 are prevalent among food-producing animals across the country.

Detection of gamma-glutamyl transpeptidase (GGT; ggt ) activity is one of the useful methods for a specific identification of Neisseria meningitidis. However, we previously happened to isolate a ggt -deficient N. meningitidis strain (NIID113) from a healthy carrier. In this study, in order to re-examine the reliability of the marker, we again investigated the GGT activity of 245 N. meningitidis human isolates and identified two other GGT-defective N. meningitidis isolates besides NIID113. The isolation frequency (1.2%) of ggt mutants among human isolates strongly confirmed the 98.8% reliability of GGT activity as the identification marker for N. meningitidis.

Leptospira meyeri were isolated from the blood or the pleural effusion cultures of four patients at a commercial clinical laboratory. All isolates were identical in their 16S rDNA sequences and NotI or SfiI restriction profiles of the chromosome DNA on pulsed-field gel electrophoresis. However, intraperitoneal inoculation of the isolate (NIID1) failed to kill hamsters and none of the patients' sera reacted with L. meyeri strains isolated, indicating leptospiral contamination occurred during laboratory investigation.

Salmonella enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones (MICs of ciprofloxacin, 0.25 to 2 microg/ml) have a mutation at codon either Ser-83 or Asp-87 of gyrA gene. A screening method by PCR-restriction fragment length polymorphism (PCR-RFLP) was designed to screen the mutations at codon Ser-83 and Asp-87 of the gyrA gene of S. enterica serovar Typhi and serovar Paratyphi A clinical isolates. This method successfully screened the gyrA mutations of S. enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones.