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)

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 bacteria genus, Legionella, includes the agents of Legionnaires' Disease, Pittsburgh pneumonia and several related infections. A number of researches have been performed in the past few years about these bacteria; many of these data are here summarized to give an idea of the most important characteristics of Legionella and of the diseases they cause.
 ...
PMID:The legionellosis. 638 May 26

The Authors reported a case of dual infection with Legionella Pneumophila and Legionella micdadei in an immunologically intact host. The bacteriological and serological data are compatible with a simultaneous recent infection.
 ...
PMID:Simultaneous infection with Legionella pneumophila and Legionella micdadei in an immunologically intact host. A case report. 646 57

We have recently shown that Legionella micdadei is ingested, but not killed, by human neutrophils. Herein we investigate the role of human monocytes in defense against this organism. Serum and monocytes from normal donors having no detectable antibody to L. micdadei were used. Egg-passaged L. micdadei organisms multiplied inside these monocytes with a peak growth of 2 log units within 12 h. No growth occurred when monocytes were omitted or when sonicated monocytes were used. Electron microscopy 18 h after infection revealed these organisms to be intracellular in normal-appearing phagosomes. When the input multiplicity of L. micdadei was greater than 1 CFU per monocyte, no intracellular growth occurred. When egg-passaged Legionella pneumophila organisms were used, intracellular organisms were found in phagosomes studded with ribosomes at the same time period. Peak intracellular growth of L. pneumophilia occurred by 48 h. L. micdadei activated the complement system and was opsonized by C3. However the use of complement-depleted (heat-inactivated) serum as the opsonic source had no effect on the bacterium's ingestion or growth in the monocyte. Thus, L. micdadei multiples in human monocytes. This entry and growth is independent of antibody or complement. The intracellular locations of L. micdadei and L. pneumophila differ, suggesting different mechanisms for the survival of these two organisms in the monocyte.
 ...
PMID:Interaction of Legionella micdadei with human monocytes. 648 Jan 16

We examined 40 strains of Legionella for reduced-oxygen scavenging enzymes. Using a simple reaction chamber with a Swinney filter for the Beers and Sizer assay, we determined the catalase activity of live cells grown on buffered charcoal-yeast extract agar. For 29 strains of Legionella pneumophila, the apparent first-order rate constants for catalase ranged from 0.000 to 0.005. Similarly, low values ranging from 0.001 to 0.005 were observed for Legionella wadsworthii, Legionella oakridgensis, and Legionella gormanii. High catalase activities were found for Legionella jordanis, Legionella longbeachae, Legionella micdadei, and Legionella bozemanii, with first-order rate constant values of 0.010 to 0.035. Cell-free extracts were analyzed for catalase, peroxidase, and superoxide dismutase. Cell-free extracts of all strains had superoxide dismutase levels ranging from 8.2 to 30.5 U per mg of protein. The species could be characterized by their catalase and peroxidase since L. pneumophila and L. gormanii had only peroxidase (relative molecular weight [Mr], 150,000); L. dumoffii had a peroxidase (Mr, 150,000) plus a catalase (Mr, 174,000); and all remaining species had catalase only (Mr, 300,000, 220,000, or 150,000).
 ...
PMID:Determination of catalase, peroxidase, and superoxide dismutase within the genus Legionella. 649 Aug 28

A systematic study of pigment production (browning) and fluorescence (extracellular yellow-green and intracellular blue-white) by nine Legionellaceae species was performed. A total of 56 strains representing Tatlockia micdadei (Pittsburgh pneumonia agent), Legionella pneumophila, Legionella jordanis, Legionella longbeachae, Legionella oakridgensis, Legionella wadsworthii, Fluoribacter bozemanae, Fluoribacter gormanii, and Fluoribacter dumoffii could be separated on media supplemented with tyrosine plus cystine, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, and 3-aminotyrosine. Parallel testing by hippurate hydrolysis and the bromocresol purple spot test enabled the identification of Legionellaceae species 24 to 72 h after primary isolation. This schema may be a practical alternative to species-specific antisera methods (slide agglutination or direct immunofluorescence) in the identification of members of the family Legionellaceae.
 ...
PMID:Clinical laboratory differentiation of Legionellaceae family members with pigment production and fluorescence on media supplemented with aromatic substrates. 654 53

Disk diffusion antimicrobial susceptibility testing of members of the family Legionellaceae was accomplished on buffered charcoal yeast extract agar by allowing the bacteria to grow for 6 h before placement of the disks, followed by an additional 42-h incubation period before the inhibitory zones were measured. This system was standardized by comparing the zone sizes with the MICs for 20 antimicrobial agents of nine bacterial strains in five Legionella species and of 19 laboratory-derived, erythromycin-resistant variants of Legionella micdadei. A high, linear correlation between zone size and MIC was found for erythromycin, trimethoprim, penicillin, ampicillin, carbenicillin, cephalothin, cefamandole, cefoxitin, moxalactam, chloramphenicol, vancomycin, and clindamycin. Disk susceptibility testing could be employed to screen Legionella isolates for resistance to any of these antimicrobial agents, of which only erythromycin is known to be efficacious in the treatment of legionellosis. With selected antibiotics, disk susceptibility patterns also appeared to accurately identify to the species level the legionellae. The range of the MICs of the legionellae for rifampin and the aminoglycosides was too small to determine whether the correlation of zone size with MIC was linear. However, laboratory-derived, high-level rifampin-resistant variants of L. micdadei demonstrated no inhibition zone around the rifampin disk, indicating that disk susceptibility testing would likely identify a rifampin-resistant clinical isolate. Of the antimicrobial agents tested, the only agents for which disk susceptibility testing was definitely not possible on buffered charcoal yeast extract agar were oxacillin, the tetracyclines, and the sulfonamides.
 ...
PMID:Disk diffusion antimicrobial susceptibility testing of members of the family Legionellaceae including erythromycin-resistant variants of Legionella micdadei. 656 6

Two children with legionellosis complicating a relapse of acute lymphoblastic leukemia are reported. A 5-year-old boy with pneumonia had Legionella pneumophila cultured from a tracheal aspirate following a rapid deterioration in his respiratory status and intubation. This child had severe and irreversible granulocytopenia and died in spite of therapy with erythromycin and rifampin added five days later. Combination antimicrobial therapy is suggested for immunosuppressed children with legionellosis if resolution of neutropenia is not readily anticipated. Culture of Legionella sp from respiratory tract secretions or sputum, as reported for the first time in the pediatric literature, should be attempted in all children in whom this infection is suspected. A 13-year-old boy with pneumonia recovered in spite of therapy with antimicrobial agents not proven to be effective against the legionellae. Clinical improvement coincided with increase in absolute granulocyte count. A retrospective diagnosis was made when seroconversion to Legionella micdadei (less than 1:16 to 1:1,024) was determined during a survey of unselected sera from 255 hospitalized children. This is the first documented case of Pittsburgh pneumonia described in a child.
 ...
PMID:Legionellosis in children with leukemia in relapse. 658 11

Titre levels against Legionella pneumophila, serotype 1-4, and against Legionella micdadei were measured in 2290 sera. About 1% contained specific antibodies indicating previous contact with the causative organisms within a year, suggesting a high incidence. On the other hand, the contagion index at 10% was relatively low. It relates to mild influenza-like and severe pneumonitic forms of the infection. In the Federal Republic of Germany it is likely that there are 6000-7000 cases of Legionella-caused pneumonia annually. With a death-rate of 15-20% there are thus likely to be between 1000 and 1500 deaths annually. This makes Legionnaire's disease the second most frequent cause of pneumonia.
 ...
PMID:[Incidence of Legionnaires' disease]. 661 6

The interaction of Legionella micdadei with human polymorphonuclear neutrophils (PMNs) and serum was investigated to determine their roles in host defense against this organism. Serum and PMNs from normal donors having no antibody to L micadei were used. PMNs phagocytized once-agar-passaged (74.6% +/- 6.5%) and twice-agar-passaged (87.3% +/- 1.0%) L micdadei less (P less than 0.05) than L micdadei passaged multiple times on agar (97.5% +/- 1.0%) or Staphylococcus aureus (98.3% +/- 0.5%). Under the same conditions, no phagocytosis of Legionella pneumophila occurred. Use of heat-inactivated serum abolished phagocytosis. PMN killing of once-agar-passaged (1.5% +/- 1.5%) and twice-agar-passaged (0) L micdadei was less (P less than 0.001) than that of L micdadei passaged multiple times on agar (88.6% +/- 4.0%) or S aureus (96.8% +/- 0.5%). L micdadei was not killed by fresh serum, although, in contrast to L pneumophila, it was opsonized by C3. Thus virulent L micdadei is phagocytized, but not killed, by human PMNs, with complement being the major opsonin.
 ...
PMID:The contribution of human neutrophils and serum to host defense against Legionella micdadei. 661 77

The protein composition of the outer membrane and the whole cell wall of 21 strains representing 14 different serotypes of seven different Legionella species has been determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The insoluble residue after extraction of cell envelopes with sodium laurylsarcosinate was considered to represent the outer membrane. Alternatively isopycnic sucrose density gradient centrifugation could be used; this approach gave similar results to the detergent method. Furthermore the effect of different methods of inactivation, e.g. treatment of the organisms with formaldehyde, heat or either on the outer membrane proteins was investigated. Each of 14 strains from seven serogroups of Legionella pneumophila yielded identical patterns of outer membrane proteins. The most prominent feature is a L. pneumophila specific major outer-membrane protein with a molecular weight of 29,000 dalton. This characteristic component was present after every method of inactivation and could also be found as a prominent protein band in total membrane preparations of non-inactivated L. pneumophila. More protein bands were observed after heat or ether inactivation than after formaldehyde inactivation. None of the other Legionella species under investigation contained the characteristic 29,000 dalton major outer membrane protein of Legionella pneumophila. Under all preparation conditions Legionella micdadei showed a characteristic intensively staining protein of 39,000 dalton. Neither the 29,000 dalton protein of L. pneumophila nor the 39,000 dalton component of L. micdadei were present in any of the other Legionella species. These other Legionella species exhibited on the contrary no single dominant membrane component but some weaker staining protein bands were observed and these were characteristic for each species. Both serogroups of Legionella longbeachae yielded identical patterns. (ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Species specific membrane proteins of Legionellaceae. 663 32


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>