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ABSTRACT: We investigated the prevalence of Legionella species isolated from puddles on asphalt roads. In addition, we carried out sequence-based typing (SBT) analysis on the genetic relationship between L. pneumophila serogroup (SG) 1 isolates from puddles and from stock strains previously obtained from sputum specimens and public baths. Sixty-nine water samples were collected from puddles on roads at 6 fixed locations. Legionella species were detected in 33 samples (47.8%) regardless of season. Among the 325 isolates from puddles, L. pneumophila SG 1 strains as a major causative agent of Legionnaires' disease were the most frequently isolated (n = 62, 19.1%). Sixty-two isolates of L. pneumophila SG 1 from puddles were classified into 36 sequence types (STs) by SBT. ST120 and ST48 were identified as major STs. Environmental ST120 strain from puddles was found for the first time in this study. Among the 14 STs (n = 19) of clinical isolates, 4 STs (n = 6, 31.6%) including ST120 were also detected in isolates from puddles on roads, and the sources of infection in these cases remained unclear. The lag-1 gene, a tentative marker for clinical isolates, was prevalent in puddle isolates (61.3%). Our findings suggest that puddles on asphalt roads serve as potential reservoirs for L. pneumophila in environment.
Applied and environmental microbiology 04/2013; · 3.69 Impact Factor
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ABSTRACT: We performed comparative analyses of Legionella pneumophila serogroup (SG) 1 isolates obtained during 2005-2012 in Toyama Prefecture, Japan, by sequence-based typing (SBT) and pulsed-field gel electrophoresis (PFGE). Seventy-three isolates of L. pneumophila SG 1, including 17 isolates from patients, 51 from public baths, 4 from cooling towers, and 1 from a shower, were analyzed. The isolates were classified into 43 sequence types (STs) by SBT and 52 types by PFGE. Fourteen STs were unique to Toyama Prefecture, as determined from the SBT database of European Working Group for Legionella Infections (EWGLI), as of October 31, 2012. ST505 strain was identified in 4 isolates from patients and 5 isolates from public baths, and these isolates belonged to 2 PFGE types. These, however, were similar because of the difference with only two restriction fragments, indicating that ST505 strain was prevalent among L. pneumophila SG 1 isolates in this area. ST505 strains isolated from patients and public baths were distributed along the river in a western part of Toyama Prefecture. SBT and PFGE profiles of 3 clinical isolates were identical with those of 3 environmental isolates from the suspected origins of the infection in each case, respectively. This finding suggested that SBT and PFGE were useful for epidemiological study. Furthermore, by SBT analysis, we identified a clonal group formed only by 7 clinical isolates that are not associated with bathwater, suggesting that they were derived from unrecognized sources.
Journal of Infection and Chemotherapy 12/2012; · 1.80 Impact Factor
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Daisuke Tanaka, Keiko Kimata,
Miwako Shimizu,
Junko Isobe,
Masanori Watahiki,
Tadahiro Karasawa,
Takayoshi Yamagishi,
Sanae Kuramoto,
Toshihiko Serikawa,
Fubito Ishiguro,
Makiko Yamada,
Kazukiyo Yamaoka,
Mitsuo Tokoro,
Toshio Fukao,
Masakado Matsumoto,
Reiji Hiramatsu,
Chie Monma,
Yoshiyuki Nagai
Japanese journal of infectious diseases 03/2007; 60(1):68-9. · 1.49 Impact Factor
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ABSTRACT: Group A Streptococci (GAS) from patients with pharyngitis and skin infections were examined for T serotypes, emm types, and streptococcal pyrogenic exotoxin gene types. The results were summarized as follows: 1) T and emm types were determined in 130 GAS isolates obtained between 2000 and 2004. Among 85 throat isolates, predominant T/emm types were T12/emm12 (25%), T4/emm4 (19%), and T1/emm1 (14%). Among 45 skin isolates, predominant T/emm types were T28/emm28 (13%), TB 3264/emm89 (13%), Tnontypeable/emm58 (13%), T1/emm1 (11%), and T12/emm12 (11%). Predominant T/emm types of skin isolates in 2000-2004 slightly differed from those during 1990s in our previous report. 2) The presence of streptococcal pyrogenic exotoxin genes in 292 GAS isolates obtained between 1990 and 2004 was examined. Significantly lower proportion of skin isolates, compared with throat isolates, was found to harbor the speA gene (12 versus 26%, respectively; p<0.01), or the speC gene (40 versus 65%, respectively; P<0.01). All but one of tested isolates carried the speB gene. The speB-negative isolate was identified as S. dysgalactiae subsp. equisimilis with the group A antigen. 3) Types of the speA alleles were determined in 59 speA-positive GAS isolates. Among 44 throat isolates, 37 (84%) were speA lineage I (speA1-speA2-speA3-speA6), and 7 (16%) were lineage II (speA4-speA5). Among 15 skin isolates, 11 (73%) were lineage I and 4 (27%) were lineage II. The pairwise associations were observed between emm type and speA allele: emm1 and speA2, emm3 and speA3, emm6 and speA4, emm11 and speA2, emm18 and speA1.
Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases 08/2005; 79(7):443-50.
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ABSTRACT: A one-shot multiplex polymerase chain reaction (PCR) was developed for detecting 12 virulence genes of diarrheagenic Escherichia coli. In order to differentiate between the five categories of diarrheagenic E. coli, we selected the target genes: stx1, stx2, and eaeA for enterohemorrhagic E. coli(EHEC); eaeA, bfpA, and EAF for enteropathogenic E. coli(EPEC); invE for enteroinvasive E. coli(EIEC); elt, estp, and esth for enterotoxigenic E. coli(ETEC); CVD432 and aggR for enteroaggregative E. coli(EAggEC); and astA distributed over the categories of diarrheagenic E. coli. In our multiplex PCR system, all 12 targeted genes (stx1, stx2, eaeA, invE, elt, estp, astA, esth, bfpA, aggR, EAF, and CVD432) were amplified in a single PCR reaction in one tube and detected by electrophoresis. Using our multiplex PCR, the 208 clinically isolated strains of diarrheagenic E. coli in our laboratory were successfully categorized and easily analyzed for the presence of virulence plasmids.
Microbiology and Immunology 02/2005; 49(6):485-92. · 1.30 Impact Factor
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ABSTRACT: Shiga-like-toxin-producing Esherichia coli O128:HNM were isolated from feces of a one-year-old boy with diarrhea and abdominal pain on July, 2002, and a 11-month-old girl with diarrhea and fever on June, 1997. None of other enteropathogenic bacteria including Salmonella were isolated. E. coli O128:HNM isolates from both patients carry stx2f and eaeA gene, but not stx1, stx2, aggR, bfpA, esth, estp, invE, astA, ureC and hlyA gene. As far as we know, this may be the first report indicating that E. coli O128:HNM carrying stx2f gene were isolated from patients in Japan.
Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases 01/2005; 78(12):1000-5.
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ABSTRACT: Mlc is a global transcriptional repressor involved in the regulation of genes linked to glucose metabolism. The activity of Mlc is modulated through the interaction with a major glucose transporter, IICBGlc, in response to external glucose. To understand how IICBGlc-Mlc interaction controls the repressor activity of Mlc, we attempted to isolate Mlc mutants that retain the ability to repress target genes even in the presence of glucose. The Mlc mutants were tested for their ability to interact with IICBGlc. Mutants in which a single amino acid substitution occurs in the N-terminal portion were no longer able to bind to IICBGlc, suggesting that the N-terminal region of Mlc is primarily responsible for the interaction with IICBGlc. To examine whether the Mlc-IICBGlc interaction and/or the membrane localization of Mlc per se are essential for the inactivation of Mlc, the properties of several hybrid proteins in which either IIBGlc or Mlc is fused to membrane proteins were analysed. The cytoplasmic IIBGlc domain failed to inhibit the Mlc action although it retains the ability to bind Mlc in cells. However, it gained the ability to inhibit the Mlc activity when it was fused to a membrane protein LacY. In addition, we showed that Mlc is inactivated when fused to membrane proteins but not when fused to cytoplasmic proteins. We conclude that the IICBGlc-Mlc interaction is dispensable for the inactivation of Mlc, and that membrane localization is directly responsible for the inactivation of Mlc.
Molecular Microbiology 09/2004; 53(3):941-51. · 5.01 Impact Factor
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Daisuke Tanaka,
Junko Isobe,
Shiho Hosorogi, Keiko Kimata,
Miwako Shimizu,
Koji Katori,
Yotaku Gyobu,
Yoshiyuki Nagai,
Takayoshi Yamagishi,
Tadahiro Karasawa,
Shinichi Nakamura
Japanese journal of infectious diseases 07/2003; 56(3):137-9. · 1.49 Impact Factor
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ABSTRACT: Background : The inhibition of β-galactosidase expression in glucose–lactose diauxie is a typical example of the glucose effect in Escherichia coli. It is generally believed that glucose exerts its effect at least partly by reducing the intracellular cAMP level. However, there is no direct evidence that the inhibitory effect of glucose on the expression of the lac operon is mediated by a reduction of the cAMP level in the glucose–lactose system.Results : To examine the roles of cAMP and the cAMP receptor protein (CRP) in the glucose effect, the intracellular levels of these factors were determined during diauxic growth in a glucose–lactose medium. We found that the levels of cAMP and CRP in a lactose-grown phase were not higher than those in a glucose-grown phase, although the cAMP levels increased transiently during the lag phase. The addition of exogenous cAMP eliminated diauxic growth but did not eliminate glucose repression. Glucose repression and diauxie were observed in cells which lack cAMP but produce a cAMP-independent CRP. In addition, inactivation of the lac repressor by the disruption of the lacI gene or the addition of IPTG, eliminated glucose repression.Conclusion : We conclude that the repression of β-galactosidase expression by glucose is not due to the reduction of the cAMP-CRP level but due to an inducer exclusion mechanism which is mediated by the phosphoenolpyruvate-dependent sugar phosphotransferase system.
Genes to Cells 02/1996; 1(3):293 - 301. · 2.68 Impact Factor
