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

Previous reports have suggested a role for natural killer (NK) cells in directly lysing host cells infected with bacteria and other intracellular microorganisms. Here, we determined the inability of a highly homogeneous population of lymphokine activated killer (LAK) cells to kill macrophages infected with the following intracellular parasites: Mycobacterium avium, Listeria monocytogenes, Legionella pneumophila, Toxoplasma gondii, and Trypanosoma cruzi. In parallel cytotoxicity assays, LAK cells lysed the tumor targets YAC-1 and P815 effectively. Furthermore, we were able to demonstrate that influenza-specific cytotoxic T lymphocytes (CTL), but not LAK cells, were efficient killers of influenza virus-infected macrophages.
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PMID:A homogeneous population of lymphokine-activated killer (LAK) cells is incapable of killing virus-, bacteria-, or parasite-infected macrophages. 210 76

Approximately 4% of recipients of solid organ transplants in the United States develop bacterial pneumonia in the posttransplant period, often in the first 3 months following transplantation. The incidence of bacterial pneumonia is highest in recipients of heartlung (22%) and liver transplants (17%), intermediate in recipients of heart transplants (5%), and lowest in renal transplant patients (1 to 2%). The crude mortality of bacterial pneumonia in solid organ transplantation has exceeded 40% in most series. Beyond those risk factors identified for nosocomial pneumonia, the occurrence of primary cytomegalovirus (CMV) infection, graft rejection, maintenance antirejection therapy with prednisone, azathioprine, and antilymphocyte globulin, antirejection therapy with high-dose corticosteroids or OKT3 and splenectomy have been associated with a significantly increased risk of bacterial pneumonia in these patients. In the first 3 months posttransplant, gram-negative bacilli, Staphylococcus aureus and Legionella predominate and mortality is very high, in excess of 60%. Thereafter, bacterial pneumonias are caused primarily by Streptococcus pneumoniae and Hemophilus influenzae, with considerably lower mortality. Bacterial pneumonia must be suspected in any transplant patient presenting with fever and cough, especially associated with dyspnea or infiltrates on chest radiograph. If large numbers of bacteria and polymorphonuclear leukocytes are not visualized in respiratory secretions the work-up should proceed directly to fiberoptic bronchoscopy with bronchoalveolar lavage and/or protected brush specimen to establish the microbiologic diagnosis as accurately as possible. For presumptive gram-negative bacillary pneumonia, the initial regimen must be effective against Pseudomonas aeruginosa. Prevention of bacterial pneumonia in transplant patients must begin with immunization against S pneumoniae and Influenza A, and include precautions taken to prevent nosocomial pneumonia. It further may include measures to prevent CMV infection and the use of trimethoprim/sulfamethoxazole prophylaxis during the first year posttransplantation. Ultimately, novel technologies such as selective antimicrobial decontamination and/or protective isolation during the early postoperative period may prove effective.
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PMID:Bacterial pneumonia in solid organ transplantation. 218 17

Since the discovery of Legionella pneumophila in the late 1970s, this organism and other Legionella sp have been an important cause of pneumonia in solid organ transplant recipients. Legionella sp are obligate aerobes that require a source of amino acids, iron, and L-cystine. Growth is enhanced in a 5% CO2 atmosphere at 37 degrees C in the presence of charcoal. Legionella sp reside in water supplies and hospital outbreaks associated with contaminated water have been described. Transplant recipients are particularly susceptible to Legionella infection. Legionella pneumonia tends to occur within several weeks after transplantation and frequently coincides with episodes of rejection. A prodrome of influenza-like symptoms is followed by a sometimes "explosive" pneumonia with patchy lobular or interstitial infiltrates on chest radiograph. High fever, abdominal pain, and mental status changes are sometimes seen. Diagnosis is made by examination of respiratory secretions by the direct fluorescent antibody technique or culture of the organism. Intravenous erythromycin is the treatment of choice. Rifampin is added if there is a lack of response. Both erythromycin and rifampin have important and opposite effects on cyclosporine metabolism, which may result, respectively, in increased cyclosporine toxicity or graft loss. Patients who must continue cyclosporine will, therefore, require frequent monitoring of cyclosporine levels.
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PMID:Legionella infection in transplant patients. 218 18

During the period from December 1989 to January 1990, An outbreak of upper respiratory infection (influenza-like syndrome) took place in the workers of a building-site in a rural area of Beijing. An epidemiological investigation and bacteriological examination were carried out in this area. The results showed that it was an outbreak of Legionnaires' Disease caused by Legionella micdadei (Lm). The incidence was 26.67% (24/90). This was the first report on Lm infection in China.
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PMID:[A preliminary investigation of an outbreak of Legionnaires' disease caused by Legionella micdadei at a building-site in the rural area of Beijing]. 226 15

Data on the clinical and laboratory study involving 150 children with the verified diagnosis of pneumonia observed as inpatients within a period from 1984 to 1988 are presented. To elucidate the pneumonia etiology, blood sera to the causative agents of influenza and parainfluenza, adenovirus, RS virus, Mycoplasma pneumoniae and Legionella pneumophila were assayed. An increase in the number of neutralizing antibodies to L. pneumophila was observed in 17.3 per cent of the patients. The majority of them simultaneously showed positive serological shifts with respect to the respiratory viruses. A specific clinical picture of pneumonia in the patients with the confirmed legionella infection was stated. The description of the treatment results is retrospective.
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PMID:[Clinical picture and treatment of Legionella pneumonia in children]. 227 89

A large outbreak of Legionnaires' disease was associated with Stafford District General Hospital. A total of 68 confirmed cases was treated in hospital and 22 of these patients died. A further 35 patients, 14 of whom were treated at home, were suspected cases of Legionnaires' disease. All these patients had visited the hospital during April 1985. Epidemiological investigations demonstrated that there had been a high risk of acquiring the disease in the out patient department (OPD), but no risk in other parts of the hospital. The epidemic strain of Legionella pneumophila, serogroup 1, subgroup Pontiac 1a was isolated from the cooling water system of one of the air conditioning plants. This plant served several departments of the hospital including the OPD. The water in the cooling tower and a chiller unit which cooled the air entering the OPD were contaminated with legionellae. Bacteriological and engineering investigations showed how the chiller unit could have been contaminated and how an aerosol containing legionellae could have been generated in the U-trap below the chiller unit. These results, together with the epidemiological evidence, suggest that the chiller unit was most likely to have been the major source of the outbreak. Nearly one third of hospital staff had legionella antibodies. These staff were likely to have worked in areas of the hospital ventilated by the contaminated air conditioning plant, but not necessarily the OPD. There was evidence that a small proportion of these staff had a mild legionellosis and that these 'influenza-like' illnesses had been spread over a 5-month period. A possible explanation of this finding is that small amounts of aerosol from cooling tower sources could have entered the air-intake and been distributed throughout the areas of the hospital served by this ventilation system. Legionellae, subsequently found to be of the epidemic strain, had been found in the cooling tower pond in November 1984 and thus it is possible that staff were exposed to low doses of contaminated aerosol over several months. Control measures are described, but it was later apparent that the outbreak had ended before these interventions were introduced. The investigations revealed faults in the design of the ventilation system.
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PMID:The Stafford outbreak of Legionnaires' disease. 234 81

Flow immunofluorescence (FIF) techniques were established for the specific detection of the bacteria Escherichia coli, Legionella pneumophila and Bacillus anthracis spores after staining with fluorescein-conjugated antibacterial antibody. For each bacterial type, a comparison was made of gating on narrow forward angle (NFA) light scatter and on the red fluorescence (Red Flu) signal available from staining with the nucleic acid dye propidium iodide. No universal gating method was found, since Bacillus spores did not take up propidium iodide and only a part of the Legionella population gave detectable NFA scatter signals. The efficiency of detecting bacteria stained with antibody remained constant with differing concentrations of the specific bacterium, and the estimate of the count for specific bacteria expressed as a fraction of the total cytometer count fell sharply with bacterial concentration. This effect was apparently due to cytometer noise inherent in the high sensitivity of detection needed for particles as small as these bacteria. The noise did not originate in the photomultipliers and was evidently the result either of light scatter from sub-micron particles in the sheath fluid or scatter from optical components. Part of the noise could be removed by selective gating, but there remained a noise component overlapping with the NFA scatter and Red Flu signals from the heterologous bacteria, i.e., those not stained with specific antibody. In consequence, at the low bacterial concentrations used no meaningful cytometer count could be obtained for the excess of the unstained bacteria and the proportion of specific bacteria in the mixed population could not, therefore, be calculated.
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PMID:Limitations of flow cytometry for the specific detection of bacteria in mixed populations. 244 82

The serologic responses to bacterial and viral antigens were determined in paired serum samples from 336 children, ages 1 month to 15 years, with roentgenographically verified community-acquired pneumonia. Significant increases in antibodies against one agent were found in 40% and against two or more agents in 8% of the children. There were significant increases in antibodies against respiratory syncytial virus in 20%, viruses of the influenza-parainfluenza group in 6% and adenovirus in 3%. A serologic response to one or more of the pneumococcal antigens used (type-specific capsular polysaccharide, C-polysaccharide and pneumolysin) was demonstrated in 13% of the patients. Ten percent of the children had significant increases in antibodies against Mycoplasma pneumoniae. Only three patients had increases against Haemophilus influenzae type b and one each against Legionella pneumophila and Chlamydia. Respiratory syncytial virus was the predominant etiologic agent in young children whereas M. pneumoniae was more frequent in the older age group.
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PMID:Etiology of community-acquired pneumonia in children based on antibody responses to bacterial and viral antigens. 251 22

A prospective one-year study of community pneumonia was conducted in Nottingham. 236 of 251 episodes of pneumonia (defined as an acute lower respiratory tract infection, for which antibiotics were prescribed, associated with new focal signs on examination of the chest) were investigated. Acute radiographic changes were present in 93 (39%). A pathogen was identified in 129 (55%) episodes, with Streptococcus pneumoniae, Haemophilus influenzae, and influenza viruses those most frequently identified. Mycoplasma pneumoniae was uncommon and infection with Legionella pneumophila was found in only 1 episode. Hospital admission was required in 52 (22%) episodes. 7 patients died (3%), all but one of the deaths occurring in patients who had been admitted to hospital. Pneumonia in the community is common but few people die of it. Initial antibiotic therapy should always cover S pneumoniae and H influenzae.
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PMID:Prospective study of the aetiology and outcome of pneumonia in the community. 288 91

In a retrospective study the serological results from 1494 patients with community-acquired pneumonia were evaluated. An infectious etiology was found in about 40% of the cases. The majority of pneumonias was caused by Mycoplasma pneumoniae and by influenza virus type A, whereas Legionella pneumophila was the fifth most frequent pathogen. In the second part of the study, 13 hospitalized patients with community-acquired pneumonia were investigated by the whole panel of routinely used microbial methods. The etiological agent was found serologically in 3 cases and in one case by cultivation. These results suggest that the determination of serum antibodies against pathogens is frequently more useful than is generally assumed, although the yield of positive results is dependent on the epidemiological situation. The detection of elevated complement-fixing titers or specific IgM antibodies often leads to diagnosis from the first serum examined.
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PMID:[Etiology of atypical pneumonias. A serological study on 1494 patients]. 300 94


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