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Biomedical subjects

Kazuhiro Tateda

Publications and source records attributed to Kazuhiro Tateda.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy of bacteriophage therapy against gut-derived sepsis caused by Pseudomonas aeruginosa in mice.

We evaluated the efficacy of bacteriophage (phage) therapy by using a murine model of gut-derived sepsis caused by Pseudomonas aeruginosa that closely resembles the clinical pathophysiology of septicemia in humans. Oral administration of a newly isolated lytic phage strain (KPP10) significantly protected mice against mortality (survival rates, 66.7% for the phage-treated group versus 0% for the saline-treated control group; P<0.01). Mice treated with phage also had lower numbers of viable P. aeruginosa cells in their blood, liver, and spleen. The levels of inflammatory cytokines (tumor necrosis factor alpha TNF-alpha, interleukin-1beta [IL-1beta], and IL-6) in blood and liver were significantly lower in phage-treated mice than in phage-untreated mice. The number of viable P. aeruginosa cells in fecal matter in the gastrointestinal tract was significantly lower in phage-treated mice than in the saline-treated control mice. We also studied the efficacy of phage treatment for intraperitoneal infection caused by P. aeruginosa and found that phage treatment significantly improved the survival of mice, but only under limited experimental conditions. In conclusion, our findings suggest that oral administration of phage may be effective against gut-derived sepsis caused by P. aeruginosa.

Administration, Oral↗
PubMed2006

Cytosolic recognition of flagellin by mouse macrophages restricts Legionella pneumophila infection.

To restrict infection by Legionella pneumophila, mouse macrophages require Naip5, a member of the nucleotide-binding oligomerization domain leucine-rich repeat family of pattern recognition receptors, which detect cytoplasmic microbial products. We report that mouse macrophages restricted L. pneumophila replication and initiated a proinflammatory program of cell death when flagellin contaminated their cytosol. Nuclear condensation, membrane permeability, and interleukin-1beta secretion were triggered by type IV secretion-competent bacteria that encode flagellin. The macrophage response to L. pneumophila was independent of Toll-like receptor signaling but correlated with Naip5 function and required caspase 1 activity. The L. pneumophila type IV secretion system provided only pore-forming activity because listeriolysin O of Listeria monocytogenes could substitute for its contribution. Flagellin monomers appeared to trigger the macrophage response from perforated phagosomes: once heated to disassemble filaments, flagellin triggered cell death but native flagellar preparations did not. Flagellin made L. pneumophila vulnerable to innate immune mechanisms because Naip5+ macrophages restricted the growth of virulent microbes, but flagellin mutants replicated freely. Likewise, after intratracheal inoculation of Naip5+ mice, the yield of L. pneumophila in the lungs declined, whereas the burden of flagellin mutants increased. Accordingly, macrophages respond to cytosolic flagellin by a mechanism that requires Naip5 and caspase 1 to restrict bacterial replication and release proinflammatory cytokines that control L. pneumophila infection.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Synthesis of Pseudomonas quorum-sensing autoinducer analogs and structural entities required for induction of apoptosis in macrophages.

The synthesis of the analogs of N-3-oxododecanoyl-L-homoserine lactone (1) and their structure-activity relationship for the apoptotic induction in macrophages, P388D1 cells, are described. It was revealed that the position of the oxo group in the acyl side chain in addition to the presence of the L-homoserine lactone unit is crucial for the apoptosis-inducing activity. Furthermore, the long acyl side chains with hydrophobic distal ends are preferable for the activity.

4-Butyrolactone↗
PubMed2006

Prevalence of Chlamydophila pneumoniae among Bangladeshi children under age 5 years with acute respiratory infections.

Despite major improvements in the diagnosis of pathogenic organisms causing acute respiratory infections (ARIs), details of infections caused by atypical pathogens are not well understood, particularly in developing countries. This clinical and epidemiological research was conducted in Bangladesh to explore the prevalence of atypical pathogens in causing childhood pneumonia. Sixty-four children with ARI were studied at the Pediatric Outpatient Department of Dhaka Medical College Hospital, Bangladesh, during September through December 2000. In addition to clinical examination, hematological, radiological, and bacteriological examinations were performed. Antibody titers from paired sera against Mycoplasma pneumoniae and Legionella spp. in the acute and convalescent phases revealed that none of these children were infected with M. pneumoniae, while only one serum sample was positive for L. pneumophila serogroup 4. Antibody titers against Chlamydophila (Chlamydia) pneumoniae, determined by an indirect microimmunofluorescence method, and by an enzyme-linked immunosorbent assay (ELISA) kit (HITAZYME C. pneumoniae kit) indicated that 13 children (20.3%) were infected with C. pneumoniae. Our results indicate a high prevalence rate of C. pneumoniae, suggesting it is as an important causative pathogen of childhood pneumonia in Bangladesh.

Acute Disease↗
PubMed2006

Semi-quantitative analysis of Streptococcus pneumoniae urinary antigen: kinetics of antigen titers and severity of diseases.

Detection of urinary antigen by a rapid immunochromatographic membrane test (Binax NOW) was widely accepted as a powerful tool for diagnosis of Streptococcus pneumoniae pneumonia. This is a qualitative kit, so the value of quantitative analysis of urinary antigen, especially correlation of antigen titers and severity of diseases, remained to be determined. We examined semi-quantitative antigen titer in urines collected from urinary antigen-proven S. pneumoniae pneumonia on admission, and analyzed the kinetics of antigen titer and its relation to severity of diseases. After serial 2-fold dilution of urine, the highest dilution for positive results was determined, and this was designated as maximum dilution factor (MDF). MDFs varied from 1 to 4096 in 29 patients examined (mean MDF, 317.8). Importantly, severe cases of S. pneumoniae pneumonia were higher values of MDFs (mean MDF: 760.5) than those of non-severe cases (mean MDF: 5.4). The patients with high MDFs (> or = 64) demonstrated higher values of LDH, CRP and lower values of WBC and PaO2 compared to those of low MDFs group (< or = 32). There was no clear correlation between CRP values and antigen titers, and conversely the majority of severe cases showed relatively weak CRP responses, despite high levels of bacterial antigen. Kinetic analysis of urinary and serum antigen titers in 4 cases of S. pneumoniae pneumonia exhibited consistently higher values of antigen titers in urine than those in serum. The half lives of urinary and serum antigen titers were calculated to be 1.0-3.4 and 1.1-2.3 weeks, respectively. These data suggest that quantitative analysis of urinary antigen may be a useful indicator for severity of disease and course of S. pneumoniae pneumonia. Our results demonstrate an application for S. pneumoniae antigen titer determination in urine and serum, which may be crucial not only for diagnostic measures, but also may provide a better understanding of the pathogenesis of S. pneumoniae infection.

Antigens, Bacterial↗
PubMed2006

'Break-point Checkerboard Plate' for screening of appropriate antibiotic combinations against multidrug-resistant Pseudomonas aeruginosa.

Increase of multiple drug resistant Pseudomonas aeruginosa (MDRP) is becoming a serious problem in the clinical setting. Although the checkerboard method to determine FIC index and synergistic effects of antibiotic combinations is useful, it is not well adapted to a routine test, mainly because of its time-consuming and labor-intensive nature. Here we report 'Break-point Checkerboard Plate', in which breakpoint concentrations, such as 'S' (sensitive) and 'I' (intermediate), were combined in a microtiter plate with 8 antibiotics, including carbapenem, aminoglycoside and fluoroquinolone. The results obtained from 12 strains of MDRP demonstrated a strong synergistic effect of some antibiotic combinations at clinically relevant concentrations. Our data suggest a usefulness of 'Break-point Checkerboard Plate' to screen appropriate antibiotic combinations against drug resistant organisms, including MDRP.

Anti-Bacterial Agents↗
PubMed2006

Identification of biochemically atypical Staphylococcus aureus clinical isolates with three automated identification systems.

Between January and April 2002, a total of 271 strains of Staphylococcus aureus were isolated from clinical specimens at Toho University Omori Hospital, Japan, including 201 (74.2 %) which were identified as meticillin-resistant S. aureus (MRSA). However, 34 (12.5 %) were biochemically atypical, because they did not produce acid on mannitol salt agar or did not agglutinate in Staphaurex testing but were categorized as MRSA by PCR analysis and by antibiotic susceptibility. Three automatic identification systems, AutoScan-4 (Dade Behring), BD Phoenix (Becton Dickinson) and Vitek 2 (bioMérieux), were evaluated by testing these atypical S. aureus isolates. The AutoScan-4 and Phoenix systems identified all 34 isolates as S. aureus. Without additional tests such as Staphaurex, observation of colony pigment and haemolysins on sheep blood agar, Vitek 2 identified only 16 isolates (47.1 %) as S. aureus with good or better confidence levels and misidentified one of the remaining isolates as Staphylococcus chromogenes. This study shows that it is possible to identify these physiologically atypical S. aureus isolates correctly by using the Phoenix and AutoScan-4 fully automatic identification systems.

Anti-Bacterial Agents↗
PubMed2006

Immunization with 3-oxododecanoyl-L-homoserine lactone-protein conjugate protects mice from lethal Pseudomonas aeruginosa lung infection.

Quorum-sensing systems have been reported to play a critical role in the pathogenesis of several bacterial infections. Recent data have demonstrated that Pseudomonas N-3-oxododecanoyl-L-homoserine lactone (3-oxo-C12-homoserine lactone, 3-oxo-C12-HSL), but not N-butanoyl-L-homoserine lactone (C4-HSL), induces apoptosis in macrophages and neutrophils. In the present study, the effects of active immunization with 3-oxo-C12-HSL-carrier protein conjugate on acute P. aeruginosa lung infection in mice were investigated. Immunization with 3-oxo-C12-HSL-BSA conjugate (subcutaneous, four times, at 2-week intervals) elaborated significant amounts of specific antibody in serum. Control and immunized mice were intranasally challenged with approximately 3 x 10(6) c.f.u. P. aeruginosa PAO1, and survival was then compared. All control mice died by day 2 post bacterial challenge, while 36 % of immunized mice survived to day 4 (P<0.05). Interestingly, bacterial numbers in the lungs did not differ between control and immunized groups, whereas the levels of pulmonary tumour necrosis factor (TNF)-alpha in the immunized mice were significantly lower than those of control mice (P<0.05). Furthermore, the extractable 3-oxo-C12-HSL levels in serum and lung homogenate were also significantly diminished in the immunized mice. Immune serum completely rescued reduction of cell viability by 3-oxo-C12-HSL-mediated apoptosis in macrophages in vitro. These results demonstrated that specific antibody to 3-oxo-C12-HSL plays a protective role in acute P. aeruginosa infection, probably through blocking of host inflammatory responses, without altering lung bacterial burden. The present data identify a promising potential vaccine strategy targeting bacterial quorum-sensing molecules, including autoinducers.

4-Butyrolactone↗
PubMed2005

Interleukin-1-deficient mice exhibit high sensitivity to gut-derived sepsis caused by Pseudomonas aeruginosa.

BACKGROUND: The role of interleukin (IL)-1 in infectious diseases is controversial; some investigators indicated an enhancing effect of IL-1 on host resistance whereas others demonstrated the protective role of IL-1 receptor antagonist in infection. We evaluated the role of endogenous IL-1 in gut-derived sepsis caused by Pseudomonas aeruginosa, by comparing IL-1-deficient mice and wild-type (WT) mice. METHODS: Gut-derived sepsis was induced by intraperitoneal injection of cyclophosphamide after colonization of P. aeruginosa strain D4 in the intestine. RESULTS: The survival rate of IL-1-deficient mice was significantly lower than that of WT mice (P<0.01). Bacterial counts in the liver, mesenteric lymph node and blood were significantly higher in IL-1-deficient mice than in WT mice. Tumor necrosis factor alpha and IL-6 in the liver were significantly higher in IL-1-deficient mice than in WT mice. In vitro, phagocytosis and cytokine production by macrophages were impaired in IL-1-deficient mice compared with WT mice. CONCLUSION: Our results indicate a critical role for IL-1 during gut-derived P. aeruginosa sepsis. The results also suggest that both impairment of cytokine production and phagocytosis by macrophages are caused by IL-1 deficiency and lead to impaired host response.

Animals↗
PubMed2005

Compensatory response of IL-1 gene knockout mice after pulmonary infection with Klebsiella pneumoniae.

This study was designed to determine the role of interleukin (IL)-1 in the inflammatory response against experimentally induced pneumonia caused by Klebsiella pneumoniae. The host immune responses of IL-1 gene knockout (IL-1 KO) mice and immunocompetent wild-type (WT) mice were compared after pulmonary infection with K. pneumoniae. There were no significant differences between the survival rates and viable bacterial counts in lungs and blood of IL-1 KO and WT mice after pulmonary infections under different conditions. Histopathological analysis showed a similar inflammatory response in both groups of mice. However, in the early stage of infection, the level of tumour necrosis factor alpha (TNF-alpha) in homogenized lungs of IL-1 KO mice was significantly higher than in WT mice. To determine the role of endogenous TNF-alpha in the recovery of the defence mechanism in IL-1 KO mice, mice were treated with an anti-TNF-alpha mAb before infection with K. pneumoniae. The results revealed a significantly lower survival rate of anti-TNF-alpha mAb-treated IL-1 KO mice than BSA-treated IL-1 KO mice. The data suggest that compensatory production of TNF-alpha in IL-1 KO mice contributes to the host defence against K. pneumoniae infection.

Animals↗
PubMed2005

Legionella pneumophila evades gamma interferon-mediated growth suppression through interleukin-10 induction in bone marrow-derived macrophages.

We examined the roles of Th1-Th2 cytokine cross talk in Legionella pneumophila-infected bone marrow-derived (BM) macrophages in the presence of costimulation with interleukin-12 (IL-12) and IL-18. Treatment with gamma interferon (IFN-gamma) alone or treatment with IL-12 in combination with IL-18 resulted in a 3- or 2-log reduction in bacterial numbers, respectively, in BM macrophages, whereas treatment with IL-12 or IL-18 alone had no effect. Significant amounts of IFN-gamma were detected in the culture supernatants of infected macrophages stimulated with IL-12 and IL-18 in combination but not independently. Neutralization of IFN-gamma by antibody completely abolished the growth inhibitory effects of IL-12 and IL-18. Interestingly, higher infectivity ratios of L. pneumophila or the addition of increasing concentrations of heat-killed bacteria (HKB) suppressed the production of IFN-gamma, which resulted in the increased intracellular growth of bacteria. Significant amounts of IL-10 were detected in culture supernatants when Legionella-infected macrophages were cocultured with HKB. Furthermore, neutralization of IL-10 by antibody resulted in an increase in IFN-gamma production by infected BM macrophages when cocultured with HKB. Treatment of HKB with trypsin but not polymyxin B attenuated the growth-promoting effects of HKB, suggesting the involvement of a protein component(s) in regulation of the growth of L. pneumophila. These findings demonstrate a crucial role of Th1-Th2 cross talk in L. pneumophila-infected BM macrophages. Our results also suggest that L. pneumophila modulates the cytokine balance from IFN-gamma-driven Th1 to more Th2 responses, likely through the induction of IL-10 by a bacterial protein component(s). These data provide new insights not only into the cellular mechanisms of Th1-Th2 cross talk in Legionella-infected macrophages but also into the pathogenesis of L. pneumophila pneumonia in humans.

Animals↗
PubMed2005

Sepsis caused by food-borne infection with Escherichia coli.

We report a case of sepsis caused by Escherichia coli (E. coli) of serotype O-143. A 78-year-old man developed symptoms of gastroenteritis after ingesting raw meat on noodles. He rapidly developed respiratory failure. Blood culture grew E. coli. The sepsis seemed to have directly spread from a food-borne infection. The development of primary sepsis after ingesting E. coli is very rare. We suspect that bacterial translocation played a major role. Serotype O-143 is recognized in enteroinvasive E. coli (EIEC) as well as in Shigella dysenteriae. The pathogen in the present case is suspected of being EIEC although the isolated E. coli strain was negative for the inv and ipa genes.

Aged↗
PubMed2005

[Evaluation of Dipstick 'Eiken' Legionella for detection of Legionella pneumophila serogroup 1 urinary antigen using the immunochromatographical method].

Dipstick 'Eiken' Legionella is a reagent for detection of Legionella pneumophila serogroup 1 antigen in urine using the immunochromatographical method. The reagent was evaluated using the reference and clinical isolated strains and clinical specimens. BinaxNOW Legionella and Legionella antigen [Mitsubishi] were evaluated simultaneously. Using four of L. pneumophila serogroup 1 strains, the minimal detectable concentration of Dipstick 'Eiken' Legionella was 5.0 x 10(4) to 2.0 x 10(5) colony forming unit/ml, it was approximate four times high in comparison with other two kits. And no positive reaction was obtained from 45 of non-L. pneumophila serogroup 1 strains. When Dipstick 'Eiken' Legionella was compared with BinaxNOW Legionella among 50 urine samples obtained from patients with pneumonia and 50 urine from healthy adults, the sensitivity was 94.7%, the specificity was 100.0% and the agreement was 99.0%. Dipstick 'Eiken' Legionella is found to be useful diagnostic reagent for Legionella infection in clinical laboratories.

Antigens, Bacterial↗
PubMed2004

In vitro antibacterial activities of new fluoroquinolones against clinical isolates of haemophilus influenzae with ciprofloxacin-resistance-associated alterations in GyrA and ParC.

BACKGROUND: The in vitro antimicrobial activities of new fluoroquinolones were tested against quinolone-resistant Haemophilus influenzae of clinical isolates. METHODS: The nucleotide sequences of the gyrA and parC genes from three ciprofloxacin-resistant strains of Haemophilus influenzae (MIC, 1.56-6.25 microg/ml) were determined. The gyrase was purified from the clinical isolates, and the inhibitory activities of quinolones against the enzyme were tested. RESULTS: These strains possessed at least one amino acid substitution in each of the GyrA (asparagine at residue 88 (Asp-88) to Tyr, Ser-84 to Leu or Ser-84 to Leu and Asp-88 to Asn) and ParC (Glu-88 to Lys). The antibacterial activity of olamufloxacin against the resistant strains was most potent compared with other quinolones, and the inhibitory activities correlated with quinolone resistance of these strains. CONCLUSIONS: These results warrant the clinical effects of new types of fluoroquinolones, such as olamufloxacin, against respiratory tract and otolaryngology infections caused by ciprofloxacin-resistant H. influenzae.

Amino Acid Sequence↗