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)

Type IV transporters are produced by several bacterial pathogens such as Agrobacterium tumefaciens, Bordetella pertussis, Brucella spp., Bartonella henselae, Helicobacter pylori and Legionella pneumophila. These transporters are critical for the pathogenic process in that they export important virulence factors across the membranes of the bacteria. Although the virulence factors that are exported by these transporters can be either nucleic acid or protein, the general mechanism of transport appears to be similar for members of this family. Recent findings have shed light on the architecture of type IV transporters and the roles that these transporters play in pathogenesis.
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PMID:Type IV transporters of pathogenic bacteria. 1261 16

This report updates, expands, and replaces the previously published CDC "Guideline for Prevention of Nosocomial Pneumonia". The new guidelines are designed to reduce the incidence of pneumonia and other severe, acute lower respiratory tract infections in acute-care hospitals and in other health-care settings (e.g., ambulatory and long-term care institutions) and other facilities where health care is provided. Among the changes in the recommendations to prevent bacterial pneumonia, especially ventilator-associated pneumonia, are the preferential use of oro-tracheal rather than naso-tracheal tubes in patients who receive mechanically assisted ventilation, the use of noninvasive ventilation to reduce the need for and duration of endotracheal intubation, changing the breathing circuits of ventilators when they malfunction or are visibly contaminated, and (when feasible) the use of an endotracheal tube with a dorsal lumen to allow drainage of respiratory secretions; no recommendations were made about the use of sucralfate, histamine-2 receptor antagonists, or antacids for stress-bleeding prophylaxis. For prevention of health-care--associated Legionnaires disease, the changes include maintaining potable hot water at temperatures not suitable for amplification of Legionella spp., considering routine culturing of water samples from the potable water system of a facility's organ-transplant unit when it is done as part of the facility's comprehensive program to prevent and control health-care--associated Legionnaires disease, and initiating an investigation for the source of Legionella spp. when one definite or one possible case of laboratory-confirmed health-care--associated Legionnaires disease is identified in an inpatient hemopoietic stem-cell transplant (HSCT) recipient or in two or more HSCT recipients who had visited an outpatient HSCT unit during all or part of the 2-10 day period before illness onset. In the section on aspergillosis, the revised recommendations include the use of a room with high-efficiency particulate air filters rather than laminar airflow as the protective environment for allogeneic HSCT recipients and the use of high-efficiency respiratory-protection devices (e.g., N95 respirators) by severely immunocompromised patients when they leave their rooms when dust-generating activities are ongoing in the facility. In the respiratory syncytial virus (RSV) section, the new recommendation is to determine, on a case-by-case basis, whether to administer monoclonal antibody (palivizumab) to certain infants and children aged <24 months who were born prematurely and are at high risk for RSV infection. In the section on influenza, the new recommendations include the addition of oseltamivir (to amantadine and rimantadine) for prophylaxis of all patients without influenza illness and oseltamivir and zanamivir (to amantadine and rimantadine) as treatment for patients who are acutely ill with influenza in a unit where an influenza outbreak is recognized. In addition to the revised recommendations, the guideline contains new sections on pertussis and lower respiratory tract infections caused by adenovirus and human parainfluenza viruses and refers readers to the source of updated information about prevention and control of severe acute respiratory syndrome.
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PMID:Guidelines for preventing health-care--associated pneumonia, 2003: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee. 1504 56

The Legionella pneumophila Dot/Icm system is a type IV secretion apparatus that transfers bacterial proteins into eukaryotic host cells. The RalF protein is a substrate engaged and translocated into host cells by the Dot/Icm system. In this study, the mechanism of Dot/Icm-mediated translocation of RalF has been investigated. It was determined that RalF translocation into host cells occurs before bacterial internalization. Sequences essential for RalF translocation were located at the C terminus of the RalF protein. A fusion protein consisting of a 20-aa C-terminal RalF peptide appended to the calmodulin-dependent adenylate cyclase domain of the Bordetella pertussis adenylate cyclase protein was translocated into host cells by the Dot/Icm system. A leucine (L372) residue at the -3 position in relation to the RalF C terminus was critical for translocation. Consistent with RalF L372 playing an important role in substrate recognition by the Dot/Icm system, most other Dot/Icm substrates were found to have amino acid residues with similar physical properties at their -3 or -4 C-terminal positions. These data demonstrate that the Dot/Icm system can transfer bacterial proteins that modulate host cellular functions before uptake and indicate that substrate recognition involves a C-terminal translocation signal. Thus, Legionella has the ability to engage synthesized substrate proteins and transfer them into host cells on contact, enabling Legionella to rapidly alter transport of the vacuole in which it resides.
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PMID:A C-terminal translocation signal required for Dot/Icm-dependent delivery of the Legionella RalF protein to host cells. 1561 86

Molecular diagnostic techniques, such as PCR, have become useful tools for the rapid etiological diagnosis of lower respiratory tract infections. Nucleic acid amplification tests (NAATs) have been evaluated for detecting most respiratory pathogens, and commercial assays are available for some pathogens. However, standardized protocols are needed before these assays are introduced into routine diagnostic use. For pneumonia, NAATs offer advantages over conventional tests for the detection of Mycoplasma pneumoniae, Legionella spp. and Chlamydia pneumoniae. For pneumococcal pneumonia in adults, PCR adds little to existing diagnostic tests, and is unable to distinguish pneumococcal colonization from infection when testing respiratory samples. Although less sensitive than culture-based methods, several commercial molecular diagnostic assays have been developed for tuberculosis and are useful rapid tests for selected patients. PCR can now be considered the rapid diagnostic test of choice for pertussis and some respiratory virus infections. Further work is required to better characterize the role of molecular diagnostic tests for diagnosing lower respiratory tract infections, and to develop standard assays that can be readily adopted by routine diagnostic laboratories.
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PMID:Molecular genetic methods in the diagnosis of lower respiratory tract infections. 1563 35

Respiratory disease caused by atypical bacteria remains an important cause of morbidity and mortality for adults and children, despite the widespread use of effective antimicrobials agents. Culture remains the "gold standard" for the detection of these agents. However, culture is labor-intensive, takes several days to weeks for growth, and can be very insensitive for the detection of some of these organisms. Newer singleplex PCR diagnostic tests are sensitive and specific, but multiple assays would be needed to detect all of the common pathogens. Therefore, we developed the Pneumoplex assays, a multiplex PCR-enzyme hybridization assay (the standard assay) and a multiplex real-time assay to detect the most common atypical pathogens in a single test. Primer and probe sequences were designed from conserved regions of specific genes for each of these organisms. The limits of detection were as follows: for Bordetella pertussis, 2 CFU/ml; for Legionella pneumophila (serotypes 1 to 15) and Legionella micdadei, 9 and 80 CFU/ml, respectively; for Mycoplasma pneumoniae, 5 CFU/ml; and for Chlamydia (Chlamydophila) pneumoniae, 0.01 50% tissue culture infective doses. Recombinant DNA controls for each of these organisms were constructed, and the number of copies for each DNA control was calculated. The Pneumoplex could detect each DNA control down to 10 copies/ml. The analytical specificity demonstrated no cross-reactivity between 23 common respiratory pathogens. One hundred twenty-five clinical bronchoalveolar lavage fluid samples tested by the standard assay demonstrated that the Pneumoplex yielded a sensitivity and a specificity of 100 and 98.5%, respectively. This test has the potential to assist clinicians in establishing a specific etiologic diagnosis before initiating therapy, to decrease hospital costs, and to prevent inappropriate antimicrobial therapy.
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PMID:The pneumoplex assays, a multiplex PCR-enzyme hybridization assay that allows simultaneous detection of five organisms, Mycoplasma pneumoniae, Chlamydia (Chlamydophila) pneumoniae, Legionella pneumophila, Legionella micdadei, and Bordetella pertussis, and its real-time counterpart. 1569 46

Moxifloxacin (Bay 12-8039) is a new 8 methoxy quinolone antibacterial. The MIC90 values are < or = 0.25 mg/l for Streptococcus pneumoniae (irrespective of penicillin susceptibility), Haemophilus influenzae (beta-lactamase positive or negative), Morexella catarrhalis, Bordetella pertussis, Legionella sp., Mycoplasma pneumoniae, Clamydia pneumoniae, Mycobacterium tuberculosis, methicillin-sensitive Staphylococcus aureus, beta-haemolytic streptococci (macrolide-sensitive or -resistant), Listeria sp., most Enterobacteriaceae, Salmonella sp., Shigella sp., Neisseria gonorrhoeae, N. menigitidis, Pasteurella spp., Vibrio spp. and Yersinia enterocolitica. For Mycobacterium intracellularae, methicillin-resistant S. aureus (MRSA), ciprofloxacin-resistant S. aureus, Citrobacter freundii, Providencia sp., Serratia sp., P. aeruginosa and other non-fermentive Gram-negative rods, MIC90s are in the range 0.5-4 mg/l. For anaerobic bacteria species, MIC90s are also in the range 0.25-4 mg/l. Moxifloxacin is bactericidal at concentrations 2- to 4-fold higher than the MIC and is rapidly bactericidal against most common pathogen groups at concentrations achieved in serum with a 400 mg dose that is between 0.5-4 mg/l. There is a post-antibiotic effect against Gram-positive and -negative bacteria. Resistant mutants are at present difficult to select in the laboratory but in general, moxifloxacin has poorer activity against strains resistant to ciprofloxacin compared to those which are susceptible. Animal and laboratory pharmacodynamic models indicate that the MIC and area under the serum concentration time curve predict outcome. Various animal models mainly of respiratory tract infection indicate equivalent or superior results compared to existing or other developmental agents. Human pharmacokinetics in healthy volunteers indicate linear pharmacokinetics over the dose range 50-800 mg/day. A single dose of 400 mg produces a maximum serum concentration of 2.5-4.5 mg/l, half-life of 11-15 h, AUC of 25-40 mg x h/l and volume of distribution of 2.5-3.5 L/kg. Protein binding is about 50% and two metabolites have been identified (M-1 and M-2). Bioavailability is > 85% and a minority of clearance is via the kidneys. No dose modification is required in renal impairment. Extra vascular penetration, where studied, is comparable to that of other quinolones. At present undergoing clinical trials, with a focus on respiratory tract infection, it is likely that moxifloxacin will provide effective therapy for pathogens with MICs of < or = 0.25-0.5 mg/l. The safety profile in a large number of human subjects is awaited.
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PMID:Moxifloxacin (Bay 12-8039): a new methoxy quinolone antibacterial. 1599 72

A multiplex PCR was developed that is capable of detecting four of the most important bacterial agents of atypical pneumonia, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis in uncultured patient specimens. These organisms cause similar symptomologies and are often not diagnosed because they are difficult to identify with classical methods such as culture and serology. Given this, the overall impact of these pathogens on public health may be grossly underestimated. The molecular test presented here provides a simple method for identification of four common, yet diagnostically challenging, pathogens.
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PMID:A multiplex PCR for detection of Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis in clinical specimens. 1602 20

Delta-9-tetrahydrocannabinol (THC) injection suppresses serum interleukin-12 (IL-12) levels in Legionella pneumophila-infected mice. Dendritic cells are a major producer of IL-12 and mouse, bone marrow-derived dendritic cell cultures produced high levels of the IL-12p40 following L. pneumophila infection. Treatment with THC suppressed this cytokine response in a concentration-dependent manner and the endocannabinoid, 2-arachidonoyolglycerol, less potently suppressed cytokine production. Dendritic cells expressed mRNA for cannabinoid receptor 1 (CB(1)), cannabinoid CB(2) receptor, and vanilloid receptor 1 (TRPV1) and the addition of the G(i) inhibitor, pertussis toxin, completely attenuated suppression induced by 3 and 6 muM THC but not by 10 muM THC. Furthermore, THC suppression was partially attenuated in dendritic cells from cannabinoid CB(1) receptor and CB(2) receptor knockout mice and in dendritic cells co-treated with THC and cannabinoid receptor antagonists. Cytokine suppression was not attenuated by pretreatment with the TRPV1 antagonist, capsazepine. These results suggest that THC-induced suppression of serum IL-12 is partly due to a suppression of IL-12 production by dendritic cells and that G(i) signaling and cannabinoid receptors, but not TRPV1, are involved in this suppressive effect.
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PMID:Role of cannabinoid receptors in Delta-9-tetrahydrocannabinol suppression of IL-12p40 in mouse bone marrow-derived dendritic cells infected with Legionella pneumophila. 1644 17

'Atypical' lower respiratory tract pathogens often cause a distinct identifiable syndrome in adults, but in children the clinical presentation of atypical, typical and viral pneumonia is less well differentiated. Specific microbiological investigations are usually required, but an understanding of their strengths and weaknesses is necessary to make interpretation possible. This review examines clinical presentation, microbiology and current evidence surrounding diagnostic techniques for Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophila psittaci, Bordetella pertussis and Legionella species. Applying an understanding of the investigations to the diagnosis of pneumonia in children may lead to more appropriate patient management by ensuring that they clarify rather than further obscure the diagnosis.
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PMID:Microbiological aspects of bacterial lower respiratory tract illness in children: atypical pathogens. 1786 19

Community-acquired pneumonia (CAP) accounts for more than two million deaths per year in children < 5 years of age. Recognition of pathogens is vital for guiding antibiotic treatment. In Gabon, no epidemiologic data on childhood CAP were available to help guide antibiotic therapy. We conducted a prospective, hospital-based, cross-sectional survey at the Albert Schweitzer Hospital, Lambarene, Gabon, to assess the importance of atypical organisms (Chlamydia pneumoniae, Mycoplasma pneumoniae, Bordetella pertussis, and Legionella pneumophila) and Streptococcus pneumoniae in the etiology of CAP in children by means of real-time polymerase chain reaction, cell culture, and serology. Collectively, atypical bacteria accounted for 11% of cases with a special emphasis on B. pertussis, accounting for 6% of cases. Clinical differentiation of atypical from typical pneumonia in children remains challenging. Molecular diagnostic methods offer fast and highly sensitive diagnostic tools and would be able to help guide antimicrobial therapy in rural areas where follow-up is difficult.
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PMID:Community-acquired pneumonia in children in Lambarene, Gabon. 1860 73


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