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

Adjuvant activity of heat-killed Legionella pneumophila was demonstrated and compared with that of inactivated Mycobacterium tuberculosis H37Rv. The two species of bacteria were suspended separately in oil and Arlacel A. Bovine serum albumin (BSA) in saline was then emulsified within the respective adjuvants and injected intradermally into guinea pigs. Antibodies to the BSA antigen in the sera of the animals were quantitated with the kinetic-dependent enzyme-linked immunosorbent assay (k-Elisa). Guinea pigs immunized with BSA in adjuvant with killed L. pneumophila produced high titers of anti-BSA antibody, which, on the average, were nearly as high as in those immunized with BSA in complete Freund's adjuvant with M. tuberculosis H37Rv, and which were much greater than in others immunized with incomplete adjuvant, lacking bacteria. Moreover, with a polypeptide hapten, the L. pneumophila evoked as much or more antibody in rabbits as the mycobacterium adjuvant. The effect of the legionella adjuvant upon the cellular immune response was examined using skin tests. For this purpose guinea pigs were immunized with picryl-guinea pig albumin in these adjuvants. 6 weeks later, they were skin-tested with that antigen. They showed reactions which appeared to have immediate as well as delayed components when examined grossly and histologically. Others, immunized with incomplete adjuvant, did not exhibit delayed reactions. Accordingly, heat-killed L. pneumophila acts as a potent adjuvant. Under the circumstances of these experiments, it was as effective as heat-killed M. tuberculosis.
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PMID:Comparative adjuvant activities of Legionella pneumophila and Mycobacterium tuberculosis. 642 49

Lipopolysaccharide (LPS) isolated from Legionella species was found to be a potent adjuvant. When Legionella LPS was injected into animals as aqueous mixture or oil emulsion with protein antigens, it potentiated humoral antibody titers to these antigens by four- to sixfold. The LPS also acted as an intrinsic adjuvant to induce delayed hypersensitivity to the cross-reacting protein antigens present in cells of Legionella species, providing a potentially useful means for detecting legionellosis by skin test. The adjuvanticity of Legionella LPS was comparable in potency to Mycobacterium tuberculosis H37Ra in Freund's complete adjuvant. However, Legionella LPS caused much less tissue inflammation and appeared to function differently in some aspects.
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PMID:Lipopolysaccharide of Legionella as adjuvant for intrinsic and extrinsic antigens. 651 22

Rifampin was studied for determination of its spectrum of activity against many bacteria of clinical importance. Most of the minimum inhibitory concentrations (MICs) were determined by agar dilution but some were determined by broth microdilution. Staphylococci were the most susceptible, with mode MICs of 0.015 microgram/ml, but most streptococcal strains, except Streptococcus faecalis, had mode MICs less than or equal to 1 microgram/ml. Haemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis, and Listeria monocytogenes were susceptible and had mode MICs of 1, 0.25, 0.03, and less than or equal to 0.12 microgram/ml, respectively. Legionella species had geometric mean MICs ranging from 0.027 to 0.25 microgram/ml. The rapidly growing mycobacteria, Mycobacterium chelonei and Mycobacterium fortuitum, were resistant, with mode of greater than 64 micrograms/ml. Enterobacteriaceae, Acinetobacter species, and Pseudomonas species had mode MICs ranging from 4 to 64 micrograms/ml. Thus, the authors conclude that, on the basis of these in vitro data and an MIC breakpoint of less than or equal to 2 micrograms/ml, gram-positive cocci (except for some enterococci), H. influenzae, N. gonorrhoeae, N. meningitidis, Legionella, and L. monocytogenes may be clinically susceptible to rifampin.
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PMID:Rifampin: spectrum of antibacterial activity. 663 33

Bacteria recently recognized as nosocomial pathogens generally fall into three categories: those that grow slowly, those that are fastidious in their nutritional or atmospheric requirements and those that resemble commensals. Each characteristic has contributed to the delay in perceiving their importance. Mycobacterium chelonei and Myco. fortuitum--which grow slowly, although characterized as "rapid-growing" mycobacteria--cause sternal osteomyelitis, pericarditis and endocarditis after cardiac surgery as well as other wound infections after many types of surgery. Myco. chelonei-like organisms have been found to cause "sterile" peritonitis in patients receiving long-term peritoneal dialysis. Legionella pneumophila and L. micdadei are fastidious bacteria that were more difficult to detect because they stain poorly with the Gram method. They cause pneumonia and lung abscess, especially in immunocompromised people. Clostridium difficile is an anaerobe that causes toxin-mediated pseudomembranous colitis in persons given antibiotics that inhibit competing gut bacteria. Chylamydia trachomatis, an intracellular organism that has not been grown in vitro, causes pneumonia and conjunctivitis in young infants who acquire the organism from their mothers at birth. Group JK bacteria cause septicemia in patients whose immune responses have been suppressed and must be distinguished from "diphtheroid" contaminants in blood cultures. Clinicians, microbiologists and epidemiologists must be alert to the characteristics of these organisms that make them easily overlooked and should also anticipate the existence of other bacteria not yet identified.
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PMID:Bacteria newly recognized as nosocomial pathogens. 700 90

Recent advances in the field of molecular biology have revolutionized our understanding of the functioning of living organisms and facilitated the development of robust tools for both diagnosis and treatment of diseases. With particular reference to the field of critical care medicine, development of molecular biology techniques have aided in the following: (1) rapid and highly specific detection of pathogenic infectious agents (eg, Mycobacterium tuberculosis, Pneumocystis carinii, cytomegalovirus, Legionella); (2) development of assays for measurement of circulating cytokines such as tumor necrosis factor (TNF) and interleukin (IL)-1 that has helped our understanding of the pathogenesis of the sepsis syndrome; (3) administration of antibodies or soluble receptors to attempt to prevent untoward effects of cytokines such as TNF or IL-1; and (4) the administration of recombinant deoxyribonucleic acid (DNA) or proteins to patients in an attempt to alter the course of a disease such as antioxidant enzymes (superoxide dismutase). The rapidity of progress in this field has been staggering, which necessitates frequent updating of our knowledge for clinicians to put these molecular tools to their best use. This brief review attempts to explain the basic principles of commonly used techniques in molecular biology including recombinant DNA, polymerase chain reaction, DNA libraries, gene therapy, and protein biochemistry in a manner that is understandable to those without an in-depth knowledge of the field.
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PMID:Current techniques in cell and molecular biology. 749 50

Quinolones are a class of antibiotics structurally related to nalidixic acid. They exhibit bactericidal activity primarily by inhibiting bacterial DNA gyrase. The early quinolones had a limited spectrum of activity, low potency, high frequency of spontaneous bacterial resistance, low serum drug concentrations and short half-lives, which virtually restricted their use to urinary tract infection. The new fluorinated quinolones differ from their predecessors in their broad antibacterial spectrum, including both Gram-negative and Gram-positive aerobic, and facultative anaerobic bacteria as well as many Mycobacterium spp., Chlamydia spp., Legionella spp. and Mycoplasma spp., in addition to many strains of bacteria that are multiresistant to beta-lactam antibiotics and aminoglycosides. They also exhibit high potency, a low incidence of resistance, high oral bioavailability, extensive tissue penetration, low protein binding and long elimination half-lives. They are generally well tolerated apart from some gastrointestinal disturbance and rashes, including photosensitive eruptions and a propensity to cause central nervous system excitation. Clinically important interactions include those with antacids, theophylline, fenbufen and warfarin. Potential toxic effects include cartilage damage, ocular toxicity, teratogenicity and impairment of spermatogenesis. The role of fluoroquinolones continues to widen, encompassing infections of the urinary tract, respiratory tract, skin and soft tissues, bone and joints, infections in immunocompromised patients, sexually transmitted diseases, infectious diarrhoea, gynaecological infections and surgical prophylaxis. The convenience of oral therapy is an added advantage of the new fluoroquinolones.
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PMID:Quinolone antibacterials. An update of their pharmacology and therapeutic use. 752 29

An insertion sequence repeated multiple times in the chromosome of Mycobacterium tuberculosis was used as a target for amplification using the polymerase chain reaction (PCR) assay for detecting Mycobacterium tuberculosis in clinical specimens. The sequences of primers were 5'-CCTGCGAGCGTAGGCGTCGG-3' (primer 1) and 5'-CTCGTCCAGCGCCGCTTCGG-3' (primer 2). One cycle of amplification consisted of denaturing at 94 degrees C for 2 min, primer annealing at 68 degrees C for 2 min, and extension at 72 degrees C for 2 min. DNA (5 fg) extracted from M. tuberculosis was detected by gel electrophoresis and Southern blot hybridization after 40 cycles of amplification. The amplification products were not obtained by DNA extracted from M. kansasii, M. intracellulare, M. avium, M. fortuitum, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Legionella pneumophila and Staphylococcus aureus; only from the M. tuberculosis complex. PCR results were compared with conventional cultural, pathological and microscopic findings in the detection of M. tuberculosis in 112 clinical specimens. There were 25 specimens that were positive for M. tuberculosis by cultural or pathological examination, of which 20 (80%) were positive by PCR. PCR detected the organism in 5 (83%) of 6 smear-positive specimens and 15 (79%) of 19 smear-negative specimens in which culture or pathology revealed M. tuberculosis. In addition, 2 smear-negative specimens and 8 smear-negative and culture-negative specimens were positive by PCR. These 10 samples were collected from the patients suspected as having tuberculosis by the clinical diagnosis based on the clinical history, characteristic radiographs, a positive PPD skin test and the effectiveness of anti-tuberculous drugs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Detection of Mycobacterium tuberculosis in clinical specimens by polymerase chain reaction method. 774 3

We have used the cryosection immunogold technique to study the composition of the Mycobacterium tuberculosis phagosome. We have used quantitative immunogold staining to determine the distribution of several known markers of the endosomal-lysosomal pathway in human monocytes after ingestion of either M. tuberculosis, Legionella pneumophila, or polystyrene beads. Compared with the other phagocytic particles studied, the M. tuberculosis phagosome exhibits delayed clearance of major histocompatibility complex (MHC) class I molecules, relatively intense staining for MHC class II molecules and the endosomal marker transferrin receptor, and relatively weak staining for the lysosomal membrane glycoproteins, CD63, LAMP-1, and LAMP-2 and the lysosomal acid protease, cathepsin D. In contrast to M. tuberculosis, the L. pneumophila phagosome rapidly clears MHC class I molecules and excludes all endosomal-lysosomal markers studied. In contrast to both live M. tuberculosis and L. pneumophila phagosomes, phagosomes containing either polystyrene beads or heat-killed M. tuberculosis stain intensely for lysosomal membrane glycoproteins and cathepsin D. These findings suggest that (a) M. tuberculosis retards the maturation of its phagosome along the endosomal-lysosomal pathway and resides in a compartment with endosomal, as opposed to lysosomal, characteristics; and (b) the intraphagosomal pathway, i.e., the pathway followed by several intracellular parasites that inhibit phagosome-lysosome fusion, is heterogeneous.
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PMID:Characterization of the Mycobacterium tuberculosis phagosome and evidence that phagosomal maturation is inhibited. 780 6

Bacterial heat shock proteins (hsp) have been shown to be important immunogens stimulating both T cells and B cells. However, little is known concerning the direct interactions between hsp and macrophages. In this study, we demonstrated that treatment of macrophage cultures with purified bacterial hsp, including Legionella pneumophila hsp60, Escherichia coli GroEL, Mycobacterium tuberculosis hsp70, Mycobacterium leprae hsp65, and Mycobacterium bovis BCG hsp65, increased the steady-state levels of cytokine mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor as well as supernatant IL-1 secretion. This effect was shown not to be due to contamination of the hsp preparations with bacterial lipopolysaccharide. However, not all hsp induced cytokines; M. tuberculosis hsp10 showed minimal activity in our study. These results suggest that bacterial hsp might modulate immunity by rapidly and directly increasing cytokine production in macrophages.
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PMID:Bacterial heat shock proteins directly induce cytokine mRNA and interleukin-1 secretion in macrophage cultures. 796 Jan 55

The application of monoclonal antibodies and DNA probes in the clinical microbiology laboratory has resulted in an array of rapid diagnostic tests. The immunofluorescent assay or enzyme-linked immunoassay is widely used in the rapid diagnosis of bacteria eg Group A streptococcus, Legionella pneumophila, Mycoplasma pneumoniae, Bordetella pertussis; parasites eg Chlamydia tachomatis, Cryptosporidium species; and fungi eg Pneumocystis carinii. The BACTEC system was first introduced to detect bacteraemia pathogens. It has been further developed to detect Mycobacterium species in clinical specimens and this has greatly reduced turn-around time in the laboratory diagnosis of Mycobacterium species. The discovery of the polymerase chain reaction has led to hopes of using it as a potential diagnostic tool in the microbiology laboratory.
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PMID:Update of the rapid diagnosis of infectious diseases. I: Bacteria, fungi and parasites. 799 14


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