The present paper deals with the occurrence of Legionella bacteria in a variety of man-made environmentalwaters, including whirlpool bathes, cooling towers and others, from April 1996 to November2000 in the eastern part of Japan around Tokyo area. A total of 2, 895 water samples were examinedfor the possible occurrence of Legionella and 904 (31%) were demonstrated to be positive. Among the various water sources, Legionella were frequently detected both in whirlpool bathes andin cooling towers, of which detection rates were 48% and 46%, respectively. More precisely, occurrenceof Legionella was higher in private-use whirlpool bathes than those for public-use; namely, thepositive rate was 71% in bathes accommodated in private houses, 63% in company's club houses, 62% in company dormitories for employees, and 51%in old-people's homes. Occurrence of Legionella, onthe other hand, was less common (≤30%) in bathes for public-use such as those installed in hotelsand in hot spring facilities. Typing of L. pneumophila serogroups revealed that SG5 (34%) was dominantin whirlpool bath waters followed by SG3 (22%), whereas SG1 (32%) was dominantly found incooling tower waters.

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We compared eight HCV screening tests for detection of anti-HCV antibody; Ortho Quick Chaser HCV Ab (QC), Ortho HCV Ab ELISA III (ELISA), Ortho HVC Ab PA test III (PA), Lumipulse II Ortho HCV (LUMI), IMx HCV·DAINAPACKII (IMx), ARCHITECT HCV (ARCH), Immucheck·F-HCV C50 Ab (Immu), RANREAM HCV Ab Ex II (RAN). Sera from six hundred patientswere examined by these eight screening tests. The positive rates of the eight screening testswere from 9.0% to 13.2%. Forty-five sera showed discrepant results between the eight screeningtests, and about half of them showed weak positive reaction and/or false positive. Twenty-five of theforty-five sera were negative for ant-HCV antibody in the CHIRON RIBA III confirmatory test, andforty-four of them were negative for HCV-RNA in the PCR method. The agreement rates betweenthe two reagents were from 95.5% to 99.2%, but were not always high between the two reagentsthat used similar antigen. The specificities and sensitivities evaluated by using the RIBA III confirmatorytest were excellent in ELISA, LUMI, IMx, ARCH and Immu. Three BBI seroconversion panelswere used to compare the positive readings in the initial stage of HCV infection by eight screeningtests. ELISA and ARCH showed the earliest positive readings, and then IMx, LUMI=RAN, PA, QC and Immu in this order. These findings indicate that ELISA and ARCH were the most excellentin the sensitivity, specificity and early diagnosis of HCV infection. However, we must pay attention tothe weak positive reaction in the screening tests, because there is a possibility of “false positive”.

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To clarify the pathogenic role of enteropathogenic Escherichia coli (EPEC) or enteroaggregative E. coli (EAggEC), the possession of eaeA gene of EPEC or aggR gene of EAggEC in the strains isolatedfrom 525 patients in sporadic diarrhea cases during 3 years (1998-2000) in Tama, Tokyo was investigatedby a PCR method. The eaeA -positive E.coli strains were confirmed from 23 cases including5 cases detected verotoxin-producing E.coli (VTEC), and those except VTEC strains (18 cases, 3.4%) were the 5th predominant enteropathogen following rotavirus, Campylobacter, adenovirus, and Salmonella. By age, 17 eaeA-positive cases were from children <10 years of age, and noticeably, ofwhich 9 were from infants <24months of age. On the other hand, although aggR -positive E.colistrains were detected from 11 cases (2.1%), of which 6 also were from infants<24 months of age.Clinical symptoms of patients whom eaeA or aggR gene-positive E.coli was isolated as the only potentialenteric pathogen were similar, showing a mild gastroenteritic features.
Only one strain of eaeA-positive E.coli and 4 of aggR -strains were typed with the commercial Oantisera, which were O55, and O86, O111 or O126. In antibiotic sensitivity tests for 9 agents, 22% of eaeA-strains and 91% of aggR-strains showed resistant, especially 10 aggR-strains had resistant toABPC. These findings suggest that these organisms are a significant causative agents of infantile diarrheaand the PCR method is a useful procedure for the diagnosis of EPEC or EAggEC infectiousdisease.

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To evaluate the prevalence of pathogenic factor-related genes in 964 O-serotype Escherichia coliisolated from sporadic diarrhea cases at 2 hospitals in Fukui during 1997 to 2001, we checked all ofthese strains for H-serotype and examined them for 4 pathogenic factor-related genes (LT, ST, stxand invE) by PCR. Of these strains, 409 except for most of 9 serotypes which are usually low prevalenceof pathogenic factor-related genes, and additional 16 strains isolated from other hospitals inFukui Prefecture were also examined for 3 pathogenic factor-related genes (eaeA, astA and aggR) by PCR.
It was found that 4 serotypes, O6: H16, O25: HNM, O111: H21 and O126: H27, were highlypositive for pathogenic factor-related genes; O6: H16 (11/12 strains) positive for LT, ST, astA, O25: HNM (10/14 strains) positive for ST and astA, O111: H21 (22/22 strains) positive for astA or aggR, and O126: H27 (8/9) positive for astA and aggR genes. According to the drug susceptibilitytest, these serotypes as O6: H16, O25: HNM, O111: H21 and O126: H27 showed a significant resistanceto some drugs in 7/12, 4/14, 21/22 and 9/9 strains, respectively.
Such results indicate that both O111 and O126-serotypes are highly positive for pathogenicfactor-related genes and also drug-resistant, namely this fact suggests that the O-serotyping as laboratoryscreening is one of the useful measures of clinical managment. Additionally, the pulsedfield gelelectrophoresis patterns found in each of the 4 serotypes mentioned revealed that a part of E. coli inFukui might be derived from the same source of infection.

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To monitor the development of specific and cross-reactive antibody response in twenty Japanesevolunteers after vaccination with live yellow fever vaccine. Serum samples were collected onvarious days after vaccination and examined for hemagglutination inhibition (HI) antibodies againstyellow fever virus (YFV), Japanese encephalitis virus (JEV) and dengue virus (DV), neutralizingantibodies against YFV and JEV, and IgM antibodies against YFV. None of the volunteers had beenpreviously immunized with this vaccine. Fifteen of 20 had pre-vaccinated with JEV 7 to 40 years before. Ten of the 20 had neutralizing antibodies against JEV before immunization.
None of the 20 had detectable antibodies against YFV or DV before vaccination. On day 10th afterthe vaccination, neutralizing antibodies to YFV were detected in 6 of 19 volunteers and IgM antibodiesagainst YFV were detected in 7 of 19. On day 14 th, HI, neutralizing, and IgM antibodiesagainst YFV were detected in all the tested sera. Neutralizing antibodies against JEV were developedin 2 volunteers and HI antibodies against JEV were increased in 3 of 6 volunteers respectively. On day 29th, cross-reactive HI antibodies for JEV and DV were detected in all the tested sera. Theresults indicate that YF vaccine induces YFV-specific antibodies in all the tested volunteers and thatit also induces HI antibodies cross-reactive for JEV and DV. The YF vaccine has a strong immunogenicitybecause it is a live vaccine, and induces antibody against YFV predominantly. The internationalcertificate of yellow fever vaccination becomes valid 10 days after vaccination. On day 14th aftervaccination, we detected neutralizing antibodies against YFV from all tested volunteers, however, only 6 of 19 volunteers had detectable neutralizing antibody on the 10th day after vaccination.Therefore, the vaccine may not be perfectly effective on day 10th after the vaccination.

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Although results of IFNα therapy in chronic hepatitis C (C-CH) patients co-infected with TT virus (TTV) have been reported, no results of IFN β therapy or IFN β and α combination therapy have beenreported. In this study, we retrospectively investigated whether co-infection with TTV affects the resultsof IFN therapy by using stored sera from 60 C-CH patients co-infected with TTV who underwent IFN β therapy or IFN β and α combination therapy. The stored sera were from 29 complete responders, 10 incompleteresponders, and 21 non-responders, and they were used for qualitative and quantitative analysis of HCV RNA, HCV genotype analysis, and qualitative and quantitative analyses of TTV DNA. TTV DNAwas detected in 23 (38.3%) of the 60 C-CH sera. The TTV DNA-positive rate was 17.2% among the completeresponders to IFN therapy, versus 58.1% in the incomplete responders and non-responders, and thedifference was significant (p<0.01). While the complete response prediction rate based on two factors, HCV RNA level and HCV genotype, was 80.8% (21/26) in the C-CH patients, the prediction rate based onthree factors, these two factors plus TTV DNA, was higher, 90.0% (18/20). It was concluded that determinationof HCV RNA concentration, HCV genotype, and TTV DNA, before IFN β therapy or IFN β and α combination therapy is useful for predicting the results of treatment of C-CH patients.

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We investigated the detection of non-specific reaction in measurement of plasma (1-3)-β-Dglucan (β-glucan) by alkaline treatment, chromogenic automated kinetic assay (alkaline-kinetic assay) and dilution and heating method, chromogenic endpoint assay (dilution heating endpoint assay).In this study, we reexamined the values of β-glucan by both methods with and without 4-amidinophenyl benzoate hydrochloride (APB) as protease inhibitor that blocks Limulus reaction inthe 142 serum samples from 142 patients who had been treated and measured β-glucan in Kawasakimedical school hospital between January 1999 and May 1999. Non-specific reactions were judged bythe calculated value under APB additive condition. The non-specific reactions were found in 135 oftotal 142 samples (95.1%) in the alkaline-kinetic assay while no non-specific reactions were recognizedin dilution heating endpoint assay. The alkaline-kinetic assay has been used widely and been evaluatedit's usefulness because of good sensitivity. However, we found very high frequency of nonspecificreaction in this method. Further studies are needed to define the reasons of non-specific reaction.On the other hand, although non-specific reactions were not detected in dilution heating endpointassay, it's clinical utilities should be evaluated in future clinical studies.

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[in Japanese]

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