Publications by authors named "Junko Amemura-Maekawa"

27 Publications

  • Page 1 of 1

Persistent Legionella contamination of water faucets in a tertiary hospital in Japan.

Int J Infect Dis 2020 Apr 5;93:300-304. Epub 2020 Mar 5.

Department of Medicine, International University of Health and Welfare Narita, 4-3, Kouzunomori, Narita-shi, Chiba, 162-8640, Japan. Electronic address:

Objective: The feasibility of the decontamination procedure for Legionella pneumophila of water systems in healthcare facilities varies by water purification and disinfection methods in each country. We evaluated the efficacy of feasible decontamination strategies in Japan.

Methods: This study was conducted at Tokyo Medical University Hospital (1015 beds) between 2015 and 2018. Samples from the water system and cooling tower were cultured periodically. Hyper-chlorination of cool tap water (>0.2 ppm), increases in the temperature of hot water (>55 °C), and flushing were used as decontamination strategies. The case of healthcare-associated legionellosis was surveyed. Environmental and clinical isolates were genotyped.

Results: 1439 environmental samples were collected; 19 (1.3%) samples tested positive for L. pneumophila from water faucets of patient rooms, toilets, waste rooms, and water sourced from wells. Genotyping of 12 isolates confirmed that the same strains were present in eight environmental isolates and two isolates from patients over three years. Although the environmental contamination of the water system was persistent, the number of positive locations of hospital environments gradually decreased; eight in 2015, four in 2016, three in 2017, and four in 2018, respectively.

Conclusions: Monitoring contamination, hyper-chlorination, controlling temperature, and flushing were effective as a Legionella decontamination strategy.
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http://dx.doi.org/10.1016/j.ijid.2020.03.002DOI Listing
April 2020

Distribution of Alleles, , and Genes of Lipopolysaccharide and Sequence-Based Types Among Serogroup 1 Isolates in Japan and China.

Front Cell Infect Microbiol 2019 5;9:274. Epub 2019 Aug 5.

State Key Laboratory for Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, China.

Approximately 85% of cases of Legionnaires' disease are caused by serogroup 1. In this study, we analyzed the distribution of alleles, and genes of lipopolysaccharide (LPS) and sequence-based types of 616 serogroup 1 strains isolated in Japan (206 clinical, 225 environmental) and China (13 clinical and 172 environmental). The gene was harbored by significantly more of the clinical isolates compared with the environmental isolates (90.3 vs. 19.1% and 61.6 vs. 3.0%, respectively; both < 0.001). genes were detected in 51.0% of Japanese clinical and 36.0% of Japanese environmental ( = 0.001) isolates, as well as 15.3% of Chinese clinical and 9.9% of Chinese environmental isolates ( = 0.544). genes were detected in 12.1% of Japanese clinical and 5.8% of Japanese environmental ( = 0.017) isolates, as well as 7.7% of Chinese clinical and 3.4% of Chinese environmental isolates ( = 0.388). The Japanese and Chinese isolates were assigned to 203 and 36 different sequence-types (ST), respectively. ST1 was predominant. Most isolates with the same ST also had the same , and gene subgroups. In conclusion, the was present in most of the clinical isolates, but was absent from most of the environmental isolates from both China and Japan, regardless of the water source and SBT type. PCR-based serotyping and subgrouping methods can be used to define a hierarchy of virulence genotypes that require stringent surveillance to prevent human disease.
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http://dx.doi.org/10.3389/fcimb.2019.00274DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691400PMC
July 2020

Legionella pneumophila and Other Legionella Species Isolated from Legionellosis Patients in Japan between 2008 and 2016.

Appl Environ Microbiol 2018 09 31;84(18). Epub 2018 Aug 31.

Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.

The Reference Center in Japan collected 427 clinical isolates between 2008 and 2016, including 7 representative isolates from corresponding outbreaks. The collection included 419 isolates, of which 372 belonged to serogroup 1 (SG1) (87%) and the others belonged to SG2 to SG15 except for SG7 and SG11, and 8 isolates of other species (, , , , , and ). isolates were genotyped by sequence-based typing (SBT) and represented 187 sequence types (STs), of which 126 occurred in a single isolate (index of discrimination of 0.984). These STs were analyzed using minimum spanning tree analysis, resulting in the formation of 18 groups. The pattern of overall ST distribution among isolates was diverse. In particular, some STs were frequently isolated and were suggested to be related to the infection sources. The major STs were ST23 (35 isolates), ST120 (20 isolates), and ST138 (16 isolates). ST23 was the most prevalent and most causative ST for outbreaks in Japan and Europe. ST138 has been observed only in Japan, where it has caused small-scale outbreaks; 81% of those strains (13 isolates) were suspected or confirmed to infect humans through bath water sources. On the other hand, 11 ST23 strains (31%) and 5 ST120 strains (25%) were suspected or confirmed to infect humans through bath water. These findings suggest that some ST strains frequently cause legionellosis in Japan and are found under different environmental conditions. serogroup 1 (SG1) is the most frequent cause of legionellosis. Our previous genetic analysis indicated that SG1 environmental isolates represented 8 major clonal complexes, consisting of 3 B groups, 2 C groups, and 3 S groups, which included major environmental isolates derived from bath water, cooling towers, and soil and puddles, respectively. Here, we surveyed clinical isolates collected from patients with legionellosis in Japan between 2008 and 2016. Most strains belonging to the B group were isolated from patients for whom bath water was the suspected or confirmed source of infection. Among the isolates derived from patients whose suspected infection source was soil or dust, most belonged to the S1 group and none belonged to the B or C groups. Additionally, the U group was discovered as a new group, which mainly included clinical isolates with unknown infection sources.
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http://dx.doi.org/10.1128/AEM.00721-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122005PMC
September 2018

A Case of Community-Acquired Pneumonia Due to Legionella pneumophila Serogroup 9 Wherein Initial Treatment with Single-Dose Oral Azithromycin Appeared Useful.

Jpn J Infect Dis 2017 Nov 11;70(6):660-662. Epub 2017 Sep 11.

Department of Bacteriology I, National Institute of Infectious Diseases.

Legionella species are important causative pathogens for severe community-acquired pneumonia (CAP). Most cases of Legionella pneumonia are due to Legionella pneumophila serogroup 1, and CAP due to L. pneumophila serogroup 9 is rare. A fourth case of CAP due to L. pneumophila serogroup 9 has been reported, and initial treatment using single-dose oral azithromycin appeared useful. Azithromycin or fluoroquinolone injection is usually recommended for the treatment of Legionella pneumonia, and no previous reports have shown the effectiveness of single-dose oral azithromycin. This case report is therefore valuable from the perspective of possible treatment for mild to moderate Legionella pneumonia using single-dose oral azithromycin.
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http://dx.doi.org/10.7883/yoken.JJID.2016.548DOI Listing
November 2017

Prevalence of Legionella species isolated from shower water in public bath facilities in Toyama Prefecture, Japan.

J Infect Chemother 2017 May 8;23(5):265-270. Epub 2017 Feb 8.

Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, Imizu-City, Toyama 939-0363, Japan.

Aims: We investigated the prevalence of Legionella spp. isolated from shower water in public bath facilities in Toyama Prefecture, Japan. In addition, we analyzed the genetic diversity among Legionella pneumophila isolates from shower water as well as the genetic relationship between isolates from shower water and from stock strains previously analyzed from sputum specimens.

Methods: The isolates were characterized using serogrouping, 16S rRNA gene sequencing, and sequence-based typing.

Results: Legionella spp. were isolated from 31/91 (34.1%) samples derived from 17/37 (45.9%) bath facilities. Isolates from shower water and bath water in each public bath facility were serologically or genetically different, indicating that we need to isolate several L. pneumophila colonies from both bath and shower water to identify public bath facilities as sources of legionellosis. The 61 L. pneumophila isolates from shower water were classified into 39 sequence types (STs) (index of discrimination = 0.974), including 19 new STs. Among the 39 STs, 12 STs match clinical isolates in the European Working Group for Legionella Infections database. Notably, ST505 L. pneumophila SG 1, a strain frequently isolated from patients with legionellosis and from bath water in this area, was isolated from shower water.

Conclusions: Pathogenic L. pneumophila strains including ST505 strain were widely distributed in shower water in public bath facilities, with genetic diversity showing several different origins. This study highlights the need to isolate several L. pneumophila colonies from both bath water and shower water to identify public bath facilities as infection sources in legionellosis cases.
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http://dx.doi.org/10.1016/j.jiac.2017.01.002DOI Listing
May 2017

Outbreak of Legionnaire's Disease Caused by Legionella pneumophila Serogroups 1 and 13.

Emerg Infect Dis 2017 02;23(2):349-351

In Japan, hot springs and public baths are the major sources of legionellosis. In 2015, an outbreak of Legionnaires' disease occurred among 7 patients who had visited a spa house. Laboratory investigation indicated that L. pneumophila serogroup 1 and 13 strains caused the outbreak and that these strains were genetically related.
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http://dx.doi.org/10.3201/eid2302.161012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324795PMC
February 2017

Variation and association of fibronectin-binding protein genes fnbA and fnbB in Staphylococcus aureus Japanese isolates.

Microbiol Immunol 2016 May;60(5):312-25

Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.

Fibronectin-binding proteins A and B (FnBPA and FnBPB) mediate adhesion of Staphylococcus aureus to fibrinogen, elastin and fibronectin. FnBPA and FnBPB are encoded by two closely linked genes, fnbA and fnbB, respectively. With the exception of the N-terminal regions, the amino acid sequences of FnBPA and FnBPB are highly conserved. To investigate the genetics and evolution of fnbA and fnbB, the most variable regions, which code for the 67th amino acids of the A through B regions (A67-B) of fnbA and fnbB, were focused upon. Eighty isolates of S. aureus in Japan were sequenced and 19 and 18 types in fnbA and fnbB, respectively, identified. Although the phylogeny of fnbA and fnbB were found to be quite different, each fnbA type connected with a specific fnbB type, indicating that fnbA and fnbB mutate independently, whereas the combination of both genes after recombination is stable. Hence those fnbA-fnbB combinations were defined as FnBP sequence types (FnSTs). Representative isolates of each FnST were assigned distinct STs by multilocus sequence typing, suggesting correspondence of FnST with genome lineage. Linkage disequilibrium (LD) analysis of the A67-B region revealed that subdomains N2, N3 and FnBR1 form a LD block in fnbA, whereas N2 and N3 form two independent LD blocks in fnbB. N2-N3 three-dimensional structural models indicated that not only the variable amino acid residues, but also well-conserved amino acid residues between FnBPA and FnBPB, are located on the surface of the protein. These results highlight a molecular process of the FnBP that has evolved by mingled mutation and recombination with retention of functions.
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http://dx.doi.org/10.1111/1348-0421.12377DOI Listing
May 2016

Diagnostic Utility of Splenial Lesions in a Case of Legionnaires' Disease due to Legionella pneumophila Serogroup 2.

Intern Med 2015 1;54(23):3079-82. Epub 2015 Dec 1.

Department of Neurology, Juntendo University Shizuoka Hospital, Japan.

We herein report the case of a 49-year-old man with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) associated with Legionnaires' disease due to Legionella pneumophila serogroup 2. Past reports suggest that Legionella infection is frequent in cases of MERS-associated pneumonia. Obtaining an early diagnosis of legionella infection is a challenge, especially if a Legionella pneumophila serogroup other than serogroup 1 contains the causative agent. In this case, the splenial lesion played an important role in recognizing the legionella infection. We suggest that legionella infection should be considered as a differential diagnosis in cases of splenial lesions associated with pneumonia.
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http://dx.doi.org/10.2169/internalmedicine.54.4872DOI Listing
August 2016

Reply to the letter to the editor by Edelstein PH.

J Infect Chemother 2015 Jan 30;21(1):77. Epub 2014 Oct 30.

Department of Respiratory Medicine, Saiseikai Yamagata Saisei Hospital, Japan.

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http://dx.doi.org/10.1016/j.jiac.2014.09.005DOI Listing
January 2015

A case of pneumonia caused by Legionella pneumophila serogroup 12 and treated successfully with imipenem.

J Infect Chemother 2014 Jun 12;20(6):390-3. Epub 2014 Mar 12.

Department of Respiratory Medicine, Saiseikai Yamagata Saisei Hospital, Japan.

The patient was an 83-year-old man hospitalized for Haemophilus influenzae pneumonia, who developed recurrent pneumonia after improvement of the initial episode. Legionella pneumophila serogroup 12 was isolated from the sputum, accompanied by increased serum antibody titers to L. pneumophila serogroup 12. Therefore, the patient was diagnosed as having Legionella pneumonia caused by L. pneumophila serogroup 12. Case reports of pneumonia caused by L. pneumophila serogroup 12 are rare, and the case described herein is the first report of clinical isolation of this organism in Japan. When the genotype was determined by the protocol of The European Working Group for Legionella Infections (Sequence-Based Typing [SBT] for epidemiological typing of L. pneumophila, Version 3.1), the sequence type was ST68. Imipenem/cilastatin therapy was found to be effective for the treatment of Legionella pneumonia in this patient.
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http://dx.doi.org/10.1016/j.jiac.2014.01.010DOI Listing
June 2014

Distribution of monoclonal antibody subgroups and sequence-based types among Legionella pneumophila serogroup 1 isolates derived from cooling tower water, bathwater, and soil in Japan.

Appl Environ Microbiol 2012 Jun 6;78(12):4263-70. Epub 2012 Apr 6.

Department of Bacteriology I, National Institute of Infectious Diseases, Sinjuku-ku, Tokyo, Japan.

Legionella pneumophila serogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates of L. pneumophila SG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW; n = 50), cooling tower water (CT; n = 50), and soil (SO; n = 35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respectively. The ratios of MAb 3/1 positive isolates were 26, 2, and 14% from BW, CT, and SO, respectively. The environmental isolates from BW, CT, and SO were divided into 34 sequence types (STs; index of discrimination [IOD] = 0.973), 8 STs (IOD = 0.448), and 11 STs (IOD = 0.879), respectively. Genetic variation among CT isolates was smaller than seen in BW and SO. ST1 accounted for 74% of the CT isolates. The only common STs between (i) BW and CT, (ii) BW and SO, and (iii) CT and SO were ST1, ST129, and ST48, respectively, suggesting that each environment constitutes an independent habitat.
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http://dx.doi.org/10.1128/AEM.06869-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3370504PMC
June 2012

[Four cases of respiratory infections caused by Legionella pneumophila serogroup 3].

Kansenshogaku Zasshi 2011 Jul;85(4):373-9

Department of Respiratory Medicine, Kurashiki Central Hospital.

Legionella pneumonia tends to be severe and is known to be fatal. Introduction of the urinary Legionella antigen test and changes in the Infectious Disease Law have led to increased numbers of reports, and milder cases are now occasionally seen. We experienced three cases demonstrating mild respiratory infections and one case demonstrating nosocomial pneumonia associated by Legionella pneumophila serogroup 3. Case 1 showed multiple ground-glass opacities on HRCT and productive cough. Cases 2 and 3 showed abnormal findings on chest X-ray, and chest CT findings in both cases suggested chronic respiratory infection. Case 4 experienced fever and hypoxia, and pulmonary edema was noted on X-ray. All of them four cases were diagnosed with respiratory infections isolated L. pneumophila serogroup 3 by culture results, and three of them cases were treated in the outpatient clinic. Thus, milder cases of Legionella pneumonia may be encountered during routine care, and tests for Legionella should be performed in such cases.
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http://dx.doi.org/10.11150/kansenshogakuzasshi.85.373DOI Listing
July 2011

Isolation of Legionella rubrilucens from a pneumonia patient co-infected with Legionella pneumophila.

J Med Microbiol 2010 Oct 17;59(Pt 10):1242-1246. Epub 2010 Jun 17.

Division of Pulmonary Medicine, Allergy and Rheumatology, Department of Internal Medicine, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka 020-8505, Japan.

We report what we believe to be the first clinical isolation of Legionella rubrilucens from a pneumonia patient co-infected with Legionella pneumophila. L. rubrilucens strains were found in both a patient's sputum and the water of a hot spring in which the patient bathed, and DNA analysis by PFGE showed that they were indistinguishable.
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http://dx.doi.org/10.1099/jmm.0.016089-0DOI Listing
October 2010

Comparison of ethidium monoazide and propidium monoazide for the selective detection of viable Legionella cells.

Jpn J Infect Dis 2010 Mar;63(2):119-23

Department of Bacteriology I, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.

Ethidium monoazide (EMA) and propidium monoazide (PMA) have been utilized for selective PCR amplification of DNA from viable bacterial cells. In this study, we compared the abilities of EMA and PMA, together with real-time PCR, to specifically distinguish dead Legionella cells from viable cells. Several experiments showed that PMA or EMA treatment could specifically prevent the PCR amplification of DNA from dead Legionella cells in water samples. However, a 4-fold higher concentration of PMA than EMA was required to achieve this effect. EMA may therefore be more useful for practical environmental investigations of Legionella.
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March 2010

Characterization of Legionella pneumophila isolates from patients in Japan according to serogroups, monoclonal antibody subgroups and sequence types.

J Med Microbiol 2010 Jun 25;59(Pt 6):653-659. Epub 2010 Feb 25.

Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.

We collected 86 unrelated clinical Legionella pneumophila strains that were isolated in Japan during the period 1980-2008. Most (80.2%) belonged to serogroup 1, followed by serogroups 5, 3 and 2. Interestingly, the patients with L. pneumophila serogroup 1 had a significantly higher male-to-female ratio (12.4) than the patients with other L. pneumophila serogroups (2.0) (OR, 10.5; 95% CI, 2.5-44.5). When the serogroup 1 strains were analysed by monoclonal antibody (mAb) typing, the most prevalent subgroup was Benidorm (34.9% of all isolates). Moreover, 79.7% of the serogroup 1 isolates were bound by mAb 3/1, which recognizes the virulence-associated epitope. When all 86 isolates were subjected to sequence-based typing (SBT) using seven loci, they could be divided into 53 sequence types (STs). The ST with the most isolates (seven) was ST1, to which most isolates from patients and environments around the world belong. However, six of the seven ST1 isolates were isolated before 1994. Other major STs were ST306 (n=6), ST120 (n=5) and ST138 (n=5). All ST306 and ST138 isolates, except for one isolate (ST306), were suspected or confirmed to be derived from bath water, which suggests that these strains prefer bath habitats. The sources of all ST1 and ST120 isolates remain unclear. By combining the SBT and mAb data, the 86 isolates could be divided into 59 types (discrimination index, 0.984). This confirms the usefulness of this combination in epidemiological studies.
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http://dx.doi.org/10.1099/jmm.0.017509-0DOI Listing
June 2010

[Legionella contamination risk factors in non-circulating hot spring water].

Kansenshogaku Zasshi 2009 Jan;83(1):36-44

Ehime Prefectural Institute of Public Health and Environmental Science.

We examined water from 182 non-circulating hot spring bathing facilities in Japan for possible Legionella occurrence from June 2005 to December 2006, finding Legionella-positive cultures in 119 (29.5%) of 403 samples. Legionellae occurrence was most prevalent in bathtub water (39.4%), followed by storage tank water (23.8%), water from faucets at the bathtub edge (22.3%), and source-spring water (8.3%), indicating no statistically significant difference, in the number of legionellae, having an overall mean of 66 CFU/100mL. The maximum number of legionellae in water increased as water was sampled downstream:180 CFU/100 mL from source spring, 670 from storage tanks, 4,000 from inlet faucets, and 6,800 from bathtubs. The majority--85.7%--of isolated species were identified as L. pneumophila : L. pneumophila serogroup (SG) 1 in 22%, SG 5 in 21%, and SG 6 in 22% of positive samples. Multivariate logistic regression models used to determine the characteristics of facilities and sanitary management associated with Legionella contamination indicated that legionellae was prevalent in bathtub water under conditions where it was isolated from inlet faucet/pouring gate water (odds ratio [OR] = 6.98, 95% confidence interval [CI] = 2.14 to 22.8). Risk of occurrence was also high when the bathtub volume exceeded 5 m3 (OR = 2.74, 95% CI = 1.28 to 5.89). Legionellae occurrence was significantly reduced when the bathing water pH was lower than 6.0 (OR = 0.12, 95% CI = 0.02 to 0.63). Similarly, occurrence was rare in inlet faucet water or the upper part of the plumbing system for which pH was lower than 6.0 (OR = 0.06, 95% CI = 0.01 to 0.48), and when the water temperature was maintained at 55 degrees C or more (OR = 0.10, 95% CI = 0.01 to 0.77). We also examined the occurrence of amoeba, Mycobacterium spp., Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus in water samples.
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http://dx.doi.org/10.11150/kansenshogakuzasshi.83.36DOI Listing
January 2009

An improved protocol for the preparation and restriction enzyme digestion of pulsed-field gel electrophoresis agarose plugs for the analysis of Legionella isolates.

Jpn J Infect Dis 2009 Jan;62(1):54-6

Department of Bacteriology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.

Pulsed-field gel electrophoresis (PFGE), which determines the genomic relatedness of isolates, is currently used for the epidemiological investigation of infectious agents such as bacteria. In particular, this method has been used for the epidemiological investigation of Legionella outbreaks. However, it takes 4 days to complete a Legionella-PFGE analysis. Due to partial digestion and DNA damage, the reproducibility of the obtained fragment digestion patterns is poor for this pathogen. In this study, we report an improved protocol that takes only 2 days to complete and that allows clear discrimination of the restriction profile with higher reproducibility than that previously achieved.
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January 2009

Distinct difference of flaA genotypes of Legionella pneumophila between isolates from bath water and cooling tower water.

Microbiol Immunol 2008 Sep;52(9):460-4

Department of Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan.

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.
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http://dx.doi.org/10.1111/j.1348-0421.2008.00060.xDOI Listing
September 2008

Specific detection of viable Legionella cells by combined use of photoactivated ethidium monoazide and PCR/real-time PCR.

Appl Environ Microbiol 2009 Jan 31;75(1):147-53. Epub 2008 Oct 31.

Department of Bacteriology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.

Legionella organisms are prevalent in manmade water systems and cause legionellosis in humans. A rapid detection method for viable Legionella cells combining ethidium monoazide (EMA) and PCR/real-time PCR was assessed. EMA could specifically intercalate and cleave the genomic DNA of heat- and chlorine-treated dead Legionella cells. The EMA-PCR assay clearly showed an amplified fragment specific for Legionella DNA from viable cells, but it could not do so for DNA from dead cells. The number of EMA-treated dead Legionella cells estimated by real-time PCR exhibited a 10(4)- to 10(5)-fold decrease compared to the number of dead Legionella cells without EMA treatment. Conversely, no significant difference in the numbers of EMA-treated and untreated viable Legionella cells was detected by the real-time PCR assay. The combined assay was also confirmed to be useful for specific detection of culturable Legionella cells from water samples obtained from spas. Therefore, the combined use of EMA and PCR/real-time PCR detects viable Legionella cells rapidly and specifically and may be useful in environmental surveillance for Legionella.
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http://dx.doi.org/10.1128/AEM.00604-08DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612233PMC
January 2009

[Largest outbreak of legionellosis associated with spa baths: comparison of diagnostic tests].

Kansenshogaku Zasshi 2007 Mar;81(2):173-82

Miyazaki Prefectural Institute for Public Health and Environment.

In July 2002, a large outbreak of legionellosis occurred in a bathhouse with spa facilities in Miyazaki Prefecture. Among the visitors, 295, including suspected cases had pneumonia and/or symptoms of fever, coughing, etc. Of these, 37% were hospitalized and 7 died. Clinical samples from 95 mainly inpatients were collected and microbiologically tested at our laboratory. Legionella pneumophila serogroup (SG) 1 was isolated from 3 of 24 in sputum culture, and none of the 3 had been treated effectively with antibiotics at sputa collection. L. pneumophila antigen in urine was detected by using enzyme immunoassay and/or immunochromatographic kits in 23 of 75 patients. Serum antibodies to L. pneumophila SG1 and Legionella dumoffii were detected in 5 each of 66 patients--9 cases including a case at mixed infection-by microplate agglutination test and/or indirect immunofluorescence assay. At our laboratory, 32 were diagnosed with legionellosis. In this outbreak, 14 were diagnosed at other laboratories, resulting in 46 confirmed cases. Urine antigen was detected more frequently by Binax NOW immunochromatographic assay than by Biotest EIA-31% versus 16% of cases tested. Both assays detected urine antigen only in samples collected within 4 weeks after onset. Antigen concentration in urine enhanced sensitivity-58% and 51%-and extended the period of antigen detection beyond 5 weeks. Both antibody titers to L. pneumophila SG1 and L. dumoffii in more than 90% of sera collected within 3 weeks after onset were < 1:16. The rate of serum antibody titer to > or = 1:128 within 3 weeks was 1.6%, during 4 to 6 weeks less than 10%, and after 7 weeks or more 8 to 25%. After an administrative report was published, L. pneumophila DNA in sputa was detected in 5 of 17 patients by nested PCR, resulting in extra 3 cases. Altogether, urinary antigen detection and PCR were more effective in laboratory diagnostic tests than culture and serology. Culture combined with molecular epidemiology is critical, however, for confirming the source of infection.
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http://dx.doi.org/10.11150/kansenshogakuzasshi1970.81.173DOI Listing
March 2007

Legionella pneumophila serogroup 1 isolates from cooling towers in Japan form a distinct genetic cluster.

Microbiol Immunol 2005 ;49(12):1027-33

Department of Bacteriology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.

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.
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http://dx.doi.org/10.1111/j.1348-0421.2005.tb03699.xDOI Listing
March 2006

[The largest outbreak of legionellosis in Japan associated with spa baths: epidemic curve and environmental investigation].

Kansenshogaku Zasshi 2005 Jun;79(6):365-74

Miyazaki Prefectural Institute for Public Health and Environment.

In July 2002, a large outbreak of legionellosis occurred in a bathhouse with spa facilities in Miyazaki Prefecture. Two hundred-ninety-five patients (including suspected cases) that had pneumonia and/or symptoms of fever, cough and so forth were reported; 37% of them were hospitalized and seven people died. In environmental investigations, Legionella pneumophila serogroups (SGs) land 8, L. dumoffii, L. londiniensis, some other Legionella species and many kinds of amoeba were isolated from 55 samples of bathtub water, tank water, filters and so forth in the spa facilities. The dominant isolates from the bathtab waters belonged to L. londiniensis, L. dumoffii and L. pneumophila SG1, and their maximum concentrations were 1.5 x 10(6), 5.2 x 10(5) and 1.6 x 10(5) cfu/100 mL, respectively. L. pneumophila SG1 strains isolated from bathtub water, tank water, filters and sputa of patients showed a indistinguishable DNA fingerprint pattern by pulsed-field gel electrophoresis (PFGE), confirming that the source of infection was the spa water. Our study indicate that spas may be a significant health hazard if hygienic management fails.
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http://dx.doi.org/10.11150/kansenshogakuzasshi1970.79.365DOI Listing
June 2005

Identification of a novel adhesion molecule involved in the virulence of Legionella pneumophila.

Infect Immun 2005 Jul;73(7):4272-80

Department of Bacteriology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.

Legionella pneumophila is an intracellular bacterium, and its successful parasitism in host cells involves two reciprocal phases: transmission and intracellular replication. In this study, we sought genes that are involved in virulence by screening a genomic DNA library of an L. pneumophila strain, 80-045, with convalescent-phase sera of Legionnaires' disease patients. Three antigens that reacted exclusively with the convalescent-phase sera were isolated. One of them, which shared homology with an integrin analogue of Saccharomyces cerevisiae, was named L. pneumophila adhesion molecule homologous with integrin analogue of S. cerevisiae (LaiA). The laiA gene product was involved in L. pneumophila adhesion to and invasion of the human lung alveolar epithelial cell line A549 during in vitro coculture. However, its presence did not affect multiplication of L. pneumophila within a U937 human macrophage cell line. Furthermore, after intranasal infection of A/J mice, the laiA mutant was eliminated from lungs and caused reduced mortality compared to the wild isolate. Thus, we conclude that the laiA gene encodes a virulence factor that is involved in transmission of L. pneumophila 80-045 and may play a role in Legionnaires' disease in humans.
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http://dx.doi.org/10.1128/IAI.73.7.4272-4280.2005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1168565PMC
July 2005

Expression of IL-6 and TNF-alpha in human alveolar epithelial cells is induced by invading, but not by adhering, Legionella pneumophila.

Microb Pathog 2004 Dec 8;37(6):295-302. Epub 2004 Dec 8.

Department of Bacteriology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.

Legionella pnemophila causes atypical pneumonia in humans, especially in patients with chronic pulmonary diseases and underlying immunosuppression, and in elderly people. Several previous studies have shown that L. pneumophila induced several inflammatory cytokines in murine macrophages, but little is known about cytokine induction by the bacterium in lung epithelial cells. In this study, we investigated the ability of L. pneumophila to stimulate the production of pro-inflammatory cytokines in the human A549 alveolar epithelial cell line during 24h exposure to 10(6), 10(7), and 10(8) microbes. Infection of the wild L. pneumophila strain to A549 resulted in increased levels of interleukin-8 (IL-8), IL-6, and tumor necrosis factor alpha (TNF-alpha) mRNA, and also the secretion of their production into culture medium. In contrast, the level of mRNAs and proteins of IL-1beta and gamma interferon (IFN-gamma) remained unchanged and undetected, respectively. Production of IL-8, IL-6, and TNF-alpha in A549 decreased when an icmE multiplication-less mutant and the heat-killed L. pneumophila strain were inoculated. The treatment of cytochalasin D, which effectively inhibited invasion of L. pneumophila into A549, significantly reduced the production of IL-6 and TNF-alpha, but not IL-8. These results suggested that the induction and expression of IL-6 and TNF-alpha in the human alveolar epithelial cells especially required intracellular signaling by L. pneumophila after invasion.
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http://dx.doi.org/10.1016/j.micpath.2004.10.002DOI Listing
December 2004

Legioliulin, a new isocoumarin compound responsible for blue-white autofluorescence in Legionella (Fluoribacter) dumoffii under long-wavelength UV light.

Biochem Biophys Res Commun 2004 Oct;323(3):954-9

Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.

Legionella dumoffii is one of the causative agents of Legionnaires' disease. There are 50 species in the genus Legionella, of which 10 species including L. dumoffii are known to exhibit uncharacterized blue-white autofluorescence. We constructed an L. dumoffii strain that exhibited a high intensity blue-white fluorescence, isolated a fluorescent pigment from the strain, and determined its molecular formula to be C(19)H(14)O(3) by high-resolution mass spectrometry. An NMR analysis revealed that this was a new isocoumarin compound, which was named legioliulin.
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http://dx.doi.org/10.1016/j.bbrc.2004.08.180DOI Listing
October 2004

Neonatal sudden death due to Legionella pneumonia associated with water birth in a domestic spa bath.

J Clin Microbiol 2003 May;41(5):2227-9

Department of Pediatrics, Nagoya Daini Red Cross Hospital, Nagoya 466-8650, Japan.

We report the first case of neonatal Legionnaires' disease associated with water birth in a spa bath at home. Legionella pneumophila serogroup 6 was detected from postmortem lung tissue.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC154682PMC
http://dx.doi.org/10.1128/jcm.41.5.2227-2229.2003DOI Listing
May 2003