Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mycobacterium tuberculosis is one of the intracellular parasitic bacteria escaping the intracellular killing inside macrophages. The aim of this symposium was to get some insight into the mechanism of pathogenicity and host defense in M. tuberculosis infection, which has not yet been elucidated well, by the presentation of up-to-date knowledge on these aspect in infection with different intracellular parasitic microbes. Dr. Yoshikai (Nagoya Univ.) indicated that TLR is involved in the initial response of host against S. choleraesuis. Among the cytokines contributing to the induction of specific immunity, the importance of IL-15 was emphasized, based on their own experimental data using IL-15 transgenic mice and the application of anti-IL-15 antibody in vivo. Dr. Yoshida (Kyushu Univ.) reviewed the mechanisms of intracellular growth of Legionellae. Several genes so far identified as essential genes in intra-macrophage growth appeared to be similar to those encoding type 3 secretion system observed in Shigellae. There is a significant strain difference in the growth of L. pneumophila inside macrophages and such difference seemed to be under the control of a gene at chromosome 13, Lgn 1. The investigation of difference in the mode of escape among various Legionella. spp. may provide a novel mechansim in bacterial invasion and escape. Dr. Kawamura (Kyoto Univ.) summarized some new reports on the molecular mechanism of the inhibition of P-L fusion by M. tuberculosis. He emphasized the importance of the alteration in phagosomal maturation as indicated by the accumulation of TACO protein. The possible involvement of TLR in the recognition of Mycobacterial cells and its LAM was discussed. Dr. Kawakami (Ryukyu Univ.) first discussed the possibility that Cryptococcus neoformans, a fungal pathogen, could be regarded as one of the intracellular parasitic microbes. His presentation mainly focused on the TH1-Th2 balance in the expression of host defense against C. neoformans in mice. From their experimental infection using attenuated strain TC-13 in various cytokine-knock out mice, the pivotal role of both IL-12 and IL-18 was clearly indicated.
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PMID:[Mechanisms of pathogenicity and host defense in infections by intracellular parasitic microbes]. 1106 72

A 67-year-old male was admitted to our hospital due to a high fever with abnormal shadows on chest X-ray films. On admission, his laboratory data showed hyponatremia, rhabdomyolysis and liver dysfunction. Encephalopathy, acute renal failure and respiratory failure developed, despite fluid management and antimicrobial therapy. His condition worsened rapidly in a few days enough to require mechanical ventilation. Legionnaires' disease was suspected, because pneumonia was found to be associated with multiple organ dysfunction. Intravenous erythromycin and methylprednisolone were administered. The patient's condition was rapidly improved, although he needed hemodialysis for 30 days. Later, indirect fluorescent antibody testing of the patient's serum against Legionella pneumophila was definitely positive (1:1024). We reported the first case of severe Legionnaires' disease in Miyazaki Prefecture, Japan.
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PMID:[A case of severe Legionnaires' disease complicated by rhabdomyolysis, acute renal failure, liver dysfunction and encephalopathy]. 1114 85

A one-year-and-seven-months-old boy was hospitalised because of fever, cough and general malaise. A diagnosed tonsillitis and pneumonia were treated with intravenous antibiotics. His clinical condition worsened despite antibiotic therapy. After immunologic investigations revealed both a cellular and a humoral immune disorder, a broncho-alveolar lavage was performed. The culture revealed Legionella pneumophila. Antibiotic treatment was then changed to erythromycin in combination with rifampicin, with a good response. Although rarely described in childhood, one should consider L. pneumophila as a possible pathogen in immunocompromised children presenting with pneumonia.
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PMID:[Pneumonia due to Legionella pneumophila in an immunocompromised child]. 1217 38

A 69-year-old man developed a cough and fever during treatment with corticosteroid (p.o. and external use) for erythroderma. Chest X-ray films revealed a consolidation shadow in the right upper lung field. Initial treatment with sulbactam sodium/ampicillin followed by imipenem/cilastatin was not effective. A urinary antigen test for Legionella was positive, making for a diagnosis of Legionella pneumonia. Intravenous treatment with ciprofloxacin (CPFX) was remarkably effective. His symptoms, chest X-ray and laboratory data rapidly improved after its initiation. Our findings strongly suggest that intravenous treatment with fluoroquinolones including CPFX should also be a first choice for Legionella pneumonia in Japan.
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PMID:Legionella pneumophila pneumonia successfully treated with intravenous ciprofloxacin. 1248 83

Legionella pneumophila endocarditis is extremely rare. The case of a fit 26 year old man who had previously undergone homograft aortic root replacement is reported. He was admitted with legionella pneumonia during the recent localised outbreak but went on to develop endocarditis. His aortic valve was replaced with a mechanical valve and he made an uneventful recovery. Public health issues and diagnosis in susceptible patients during localised outbreaks are discussed.
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PMID:Innocent victim of a localised outbreak: legionella endocarditis. 1269 81

To date, 24 Legionella pneumophila genes (icm and dot genes) have been shown to be required for intercellular growth and host cell killing. A previous report indicated that the regulation of these genes is complicated and probably involves several regulatory proteins. In this study, a genetic screen performed in Escherichia coli identified the CpxR response regulator as an activator of the L. pneumophila icmR gene. Construction of an L. pneumophila cpxR insertion mutant showed that the expression of icmR is regulated by CpxR. In addition, a conserved CpxR binding site (GTAAA) was identified in the icmR regulatory region and L. pneumophila His-tagged CpxR protein was shown to bind to the icmR regulatory region using a mobility shift assay. Besides its dramatic effect on the icmR level of expression, the CpxR regulator was also found to affect the expression of the icmV-dotA and icmW-icmX operons, but to a lesser extent. The role of CpxA, the cognate sensor kinase of CpxR, was also examined and its effect on the icmR level of expression was found to be less pronounced than the effect of CpxR. The RpoE sigma factor, which was shown to coregulate genes together with CpxR, was examined as well, but it did not influence icm and dot gene expression. In addition, when the cpxR mutant strain, in which the expression of the icmR gene was dramatically reduced, and the cpxA and rpoE mutant strains were examined for their ability to grow inside Acanthamoeba castellanii and HL-60-derived human macrophages, no intracellular growth defect was observed. This study presents the first evidence for a direct regulator (CpxR) of an icm-dot virulence gene (icmR). The CpxR regulator together with other regulatory factors probably concerts with the expression of icm and dot genes to result in successful infection.
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PMID:Identification of CpxR as a positive regulator of icm and dot virulence genes of Legionella pneumophila. 1289 11

A 64-year-old man was referred to us because of pneumonia refractory to panipenem/betamipron. His chest radiography showed patchy consolidations in the lower lobe of the right lung and in the middle field of the left lung, and severe hypoxia was present. He was diagnosed as having acute respiratory distress syndrome due to severe pneumonia, and was treated with pulse methylprednisolone and sivelestat sodium in combination with intravenous erythromycin and ciprofloxacin. The patient recovered with this treatment. Serological examination using blood samples collected on the 12th and 28th hospital days revealed elevation of anti-L. pneumophila serogroup I antibody. It is suggested that administration of methylprednisolone and sivelestat sodium in combination with intravenous erythromycin and ciprofloxacin in a case of severe Legionella pneumonia complicated with acute respiratory distress syndrome is effective, and may be of use in similar cases.
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PMID:[A case of Legionella pneumonia complicated with acute respiratory distress syndrome treated with methylprednisolone and sivelestat sodium in combination with intravenous erythromycin and ciprofloxacin]. 1565 Dec 76

A 75 year-old male was admitted to our hospital with high fever and dyspnea. He had traveled in Turkey 10 days before. His chest X-ray showed infiltrations in bilateral lower lung fields. His urinary antigen detection test for Legionella pneumophilia was positive. He was treated with pazufloxacin added to clarithromycin and his symptons were promptly resolved.
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PMID:[A travel abroad-associated case of Legionella pneumonia diagnosed by urinary antigen detection test]. 1597 68

An ultrasonic treatment system, using a TiO2 photocatalyst, was used to disinfect Legionella pneumophila. A kinetic study of the process indicates that TiO2 significantly improves the disinfection process. The concentrations of viable cells were reduced to 6% of the initial concentrations in the presence of 0.2g/ml TiO2 after a 30 min of treatment period, while only an 18% reduction was observed in the absence of TiO2 . The potency of the disinfection could be enhanced, to some extent, by increasing the amount of TiO2 used. Cell concentrations were decreased by an order of 3 within 30 min of treatment in the presence of 1.0 g/ml TiO2 . The disinfection power in the presence of TiO2 versus Al2O3 was also compared and the findings showed that TiO2 induced a higher cell killing. No significant effect of initial cell concentration on the disinfection was found in the range of 10(2)-10(7) CFU/ml after a 30 min of treatment period. The mechanism of cell killing was investigated by examining the effects of OH radical scavengers such as ascorbic acid, histidine and glutathione. The disinfection power was reduced in samples that contained these radical scavengers, thus indicating the importance of OH radicals.
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PMID:Disinfection of Legionella pneumophila by ultrasonic treatment with TiO2. 1651 3

The heme cofactor in soluble guanylate cyclase (sGC) is a selective receptor for NO, an important signaling molecule in eukaryotes. The sGC heme domain has been localized to the N-terminal 194 amino acids of the beta1 subunit of sGC and is a member of a family of conserved hemoproteins, called the H-NOX family (Heme-Nitric Oxide and/or OXygen-binding domain). Three new members of this family have now been cloned and characterized, two proteins from Legionella pneumophila (L1 H-NOX and L2 H-NOX) and one from Nostoc punctiforme (Np H-NOX). Like sGC, L1 H-NOX forms a 5-coordinate Fe(II)-NO complex. However, both L2 H-NOX and Np H-NOX form temperature-dependent mixtures of 5- and 6-coordinate Fe(II)-NO complexes; at low temperature, they are primarily 6-coordinate, and at high temperature, the equilibrium is shifted toward a 5-coordinate geometry. This equilibrium is fully reversible with temperature in the absence of free NO. This process is analyzed in terms of a thermally labile proximal Fe(II)-His bond and suggests that in both the 5- and 6-coordinate Fe(II)-NO complexes of L2 H-NOX and Np H-NOX, NO is bound in the distal heme pocket of the H-NOX fold. NO dissociation kinetics for L1 H-NOX and L2 H-NOX have been determined and support a model in which NO dissociates from the distal side of the heme in both 5- and 6-coordinate complexes.
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PMID:Nitric oxide binding to prokaryotic homologs of the soluble guanylate cyclase beta1 H-NOX domain. 1672 1


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