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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An epidemiological link was found between contamination of a hospital water-supply by Legionella pneumophila and by Pittsburgh pneumonia agent (PPA) and subsequent cases of nosocomial legionnaires' disease and Pittsburgh pneumonia. The extent of L pneumophila isolation from the water-supply paralleled the occurrence of disease. Whenever L pneumophila was isolated from more than 30% of ten selected water sites, nosocomial legionellosis occurred. The temperature of the hot water tanks was raised to 60-77 degrees C for 72 h, and water outlets were flushed for 30 min with hot water. A decline in numbers of L pneumophila and PPA in the water-supply was followed by a fall in the incidence of legionnaires' disease and Pittsburgh pneumonia. In addition, intermittent raising of the temperature in the hot water system decreased both the number of months in which disease occurred and the proportion of nosocomial pneumonias caused by these organisms.
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PMID:Legionellaceae in the hospital water-supply. Epidemiological link with disease and evaluation of a method for control of nosocomial legionnaires' disease and Pittsburgh pneumonia. 613 32

The objective of this study was to evaluate by relatively simple metabolic tests the usefulness of buffers and energy sources commonly used in Legionella growth media. Legionella pneumophila serogroups 1 to 6, Legionella micdadei, and Legionella bozemanii were grown in an enriched charcoal-yeast extract diphasic medium. The cells were washed thrice, suspended in various buffers (pH 6.9) with 1 or 5 mM MgSO4, and used immediately or after controlled-rate cryopreservation. CO2 produced and C incorporated into the cold trichloracetic acid-insoluble fractions from 14C-labeled substrates were determine. Potassium phosphate buffer (0.02 M) was as satisfactory as organic buffers for glutamate metabolism, but the addition of KCl or NaCl reduced activity. Metabolic activity for glutamate was not lost upon cryopreservation, and cryopreserved cells were used to test the utilization of other single or paired substrates. Rates of activity for serine, glutamate, threonine, and pyruvate, in this descending order, were high, and those for alpha-ketoglutarate, succinate, and gamma-aminobutyrate were low. Although glutamine was not used as rapidly as glutamate, when added to glutamate it was preferentially metabolized, possibly because of more rapid transport. When glutamate and serine were combined, glutamate furnished more C for CO2 and less for incorporation, whereas the reverse was true of serine. In conclusion, glutamate as an energy source may in some cases spare other amino acids for synthesis. alpha-Ketoglutarate, a common constituent of Legionella media, may reduce oxygen toxicity but is probably not a chief energy source.
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PMID:Substrate utilization by Legionella cells after cryopreservation in phosphate buffer. 614 14

Following the discovery of Legionella pneumophila as the cause of an epidemic of pneumonia at an American Legion convention in Philadelphia, a group of related bacteria were recognized as additional human pathogens. This newly established bacterial genus, Legionella, includes the agents of Legionnaires' disease, Pittsburgh pneumonia, and several related infections. There are many similarities in the pathology of human infection caused by all the Legionella species. All produce a severe confluent lobular or lobar pneumonia, and abscess formation is not uncommon. A leukocytoclastic inflammatory infiltrate of neutrophils and macrophages, "septic" vasculitis of small blood vessels, coagulation necrosis, and focal septal disruption are characteristic but not diagnostic features. The inflammatory response is clearly that of a bacterial pneumonia with a necrotizing component, and does not resemble most mycoplasmal, chlamydial, or viral pneumonias. The bacteria can be demonstrated well by special stains. Acid fastness of Legionella micdadei, the cause of Pittsburgh pneumonia, is a helpful presumptive clue to diagnosis. The bacteria can be presumptively speciated in tissue by direct immunofluorescence. In addition, reliable recovery of the organisms on agar media now allows a specific diagnosis to be made. As a group, these infections are properly referred to as the Legionella pneumonias.
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PMID:The pathology of the Legionella pneumonias. A review of 74 cases and the literature. 616 29

The antigens of the six serogroups of Legionella pneumophila were compared by two-dimensional (crossed) immunoelectrophoresis by using rabbit antisera to serogroups 1, 2, 3 and 4. The close relationship among the serogroups was shown by the fact that 27 of the 31 antigens demonstrated so far were common. However, distinctive group-specific antigens with slow electrophoretic mobility were observed for serogroups 1, 2, 3, and 4. When intact serogroup 1 organisms were extracted with EDTA, the group-specific antigen was recovered in a virtually pure form. The group-specific antigen was pronase resistant, heat stable, and amphiphilic and had a surface location, all of which are properties suggestive of lipopolysaccharide. L. pneumophila shared four to five antigens with Tatlockia micdadei (Legionella micdadei). The large number of common antigens in the serogroups of L. pneumophila has important implications for the specific detection of antigens and antibodies by fluorescent and other tagged antibody methods.
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PMID:Antigenic analysis of Legionella pneumophila and Tatlockia micdadei (Legionella micdadei) by two-dimensional (crossed) immunoelectrophoresis. 617 28

Proteinases produced by various Legionella species were studied by means of caseinate precipitation. Proteinase production was particularly high in strains of Legionella pneumophila (serogroups 1-6), much lower in other Legionella species, and absent in Legionella micdadei strain Tatlock. Immunoglobulins against proteinases of Legionella pneumophila (serogroup 1, strain Philadelphia 1) inhibited the proteinase activity of all strains of Legionella pneumophila, Legionella bozemanii, Legionella dumoffi and Legionella gormanii. There was no cross-reactivity between these antibodies and proteinases from bacteria belonging to other genera. Antibodies against Legionella pneumophila proteinases were not found in human convalescent sera. The proteinases of Legionella species could possibly be associated with pathogenicity factors.
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PMID:Occurrence and immunogenicity of proteinases from Legionella species. 618 21

From July 1977 to January 1980, 5 cases of pneumonia owing to Pittsburgh pneumonia agent and 4 cases owing to Legionella pneumophila occurred in our renal transplant population. Comparison of the clinical manifestations, laboratory features an radiographic changes demonstrated no unique characteristics that allowed differentiation from other bacterial pneumonias. Diagnosis in all cases required histologic or serologic identification of the infecting organism. We herein present our protocol for establishing rapidly the diagnosis of pneumonia in renal transplant patients with emphasis on the use of open lung biopsy.
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PMID:Opportunistic lung infections in renal transplant patients: a comparison of Pittsburgh pneumonia agent and legionnaires' disease. 625 77

The difficulties associated with the growth of Legionella species in common laboratory media may be due to the sensitivity of these organisms to low levels of hydrogen peroxide and superoxide radicals. Exposure of yeast extract (YE) broth to fluorescent light generated superoxide radicals (3 microM/h) and hydrogen peroxide (16 microM/h). Autoclaved YE medium was more prone to photochemical oxidation than YE medium sterilized by filtration. Activated charcoals and, to a lesser extent, graphite, but not starch, prevented photochemical oxidation of YE medium, decomposed hydrogen peroxide and superoxide radicals, and prevented light-accelerated autooxidation of cysteine. Also, suspensions of charcoal in phosphate buffer and in charcoal yeast extract medium readily decomposed exogenous peroxide (17 and 23 nmol/ml per min, respectively). Combinations of bovine superoxide dismutase and catalase also decreased the rate of photooxidation of YE medium. Medium protected from light did not accumulate appreciable levels of hydrogen peroxide, and autoclaved YE medium protected from light supported good growth of Legionella micdadei. Various species of Legionella (10(4) cells per ml) exhibited sensitivity to relatively low levels of hydrogen peroxide (26.5 microM) in challenge experiments. The level of hydrogen peroxide that accumulated in YE medium over a period of several hours (greater than 50 microM) was in excess of the level tolerated by Legionella pneumophila, which contained no measurable catalase activity. Strains of L. micdadei, Legionella dumoffi, and Legionella bozmanii contained this enzyme, but the presence of catalase did not appear to confer appreciable tolerance to exogenously generated hydrogen peroxide.
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PMID:Production of superoxide and hydrogen peroxide in medium used to culture Legionella pneumophila: catalytic decomposition by charcoal. 630 19

We review the current knowledge concerning this newly recognized pathogen, Pittsburgh pneumonia agent (PPA), and present a new, comprehensive perspective of PPA based on our extensive clinical experience: 1) PPA pneumonia is more common and affects a broader range of patients than previously appreciated. 2) In the general population, the disease is not distinguishable from acute pneumonia due to other causes. Because specialized diagnostic tests are required for detection, it is likely that many cases in other hospitals go unrecognized. 3) Diagnosis is important, as erythromycin appears to improve outcome, whereas beta-lactam antibiotics and aminoglycosides, frequently used as empiric therapy for nosocomial bacterial pneumonias, do not. 4) The presence of both PPA and L. pneumophila in the same environmental sites, and the discovery of seven cases of simultaneous infection by both organisms suggest that both organisms are likely to share a common reservoir within the hospital and a common mode of transmission. 5) PPA infection occurs in a more debilitated population than does Legionnaires' disease. This may represent differences in intensity of exposure to the two organisms or may reflect inherent differences in virulence.
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PMID:Pneumonia due to the Pittsburgh pneumonia agent: new clinical perspective with a review of the literature. 633 42

We wanted to determine the prevalence of pneumonias caused by Legionella species among patients on whom autopsies were performed in two medical centers in St Louis from January 1976 to June 1981. We screened formaldehyde-fixed deparaffinized lung tissue sections with microscopic evidence of pneumonia from 97 patients with use of the direct immunofluorescence antibody technique with a multivalent antilegionella conjugate containing antibodies to Legionella pneumophila serogroups 1 through 4 plus other Legionella species. One patient (1%) had disseminated L pneumophila serogroup 1 infection. We conclude that the prevalence of pneumonias caused by L pneumophila (serogroups 1 through 4), Legionella micdadei, Legionella bozemanii, Legionella dumoffii, or Legionella gormanii is low in the patients studied.
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PMID:Prevalence of pneumonias caused by Legionella species among patients on whom autopsies were performed. 634 38

In an analysis of legionellosis at Presbyterian-University Hospital in Pittsburgh during the 28 months after the original outbreak of pneumonia caused by Legionella micdadei , 101 consecutive renal-allograft recipients were studied. The prevalence of elevated titers of antibody to Legionella pneumophila or L. micdadei among the patients at the time of transplantation (21.6%) was not significantly different from that among kidney donors (13.4%; P greater than .25). Seroconversion occurred in 21 (23.6%) of 89 recipients during the six months after transplantation. Seven recipients who seroconverted were diagnosed as having legionella pneumonia, eight had fever and pneumonitis attributed to other causes but compatible (on clinical grounds) with legionella infection, and six had no clinical evidence of infectious pneumonia. The interval from transplantation to onset of pneumonia was shorter for recipients with evidence of L. micdadei pneumonia than for patients with L. pneumophila pneumonia (P = .006); this finding suggested that the former disease occurred when the recipients were most immunocompromised. The original outbreak of L. micdadei pneumonia was found to have subsided nine months after the last formally recognized case, but infections with L. pneumophila continued to occur thereafter.
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PMID:Infections caused by Legionella micdadei and Legionella pneumophila among renal transplant recipients. 637 65


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