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)

The past decade has seen the rapid advancement of molecular biology and its application in the field of infectious diseases. The polymerase chain reaction (PCR) is a technique which brings about the in vitro amplification of DNA, and is clinically useful in the sensitive, specific and rapid diagnosis of various infectious diseases. The fast diagnosis of viral infections using PCR is a prime example, since viral culture may take weeks to grow and since serologic conversion seldom occurs until the convalescent phase of the clinical illness. Similarly, PCR is applicable to the diagnosis of pulmonary infections caused by mycobacteria, Legionella, methicillin-resistant Staphylococcus aureus, anaerobes, Mycoplasma, Chlamydia, Pneumocystis carinii and so on. On the other hand, the drug-resistant phenotype of a microorganism is predictable by the detection of gene alterations related to the drug resistance. For example, the deletion of the catalase-peroxidase gene relating to isoniazid resistance of mycobacteria, and point mutations in the RNA polymerase beta subunit (rpoB) gene relating to rifampicin resistance have been elucidated. As these applied techniques become more widely available and less costly, they should contribute not only to the rapid diagnosis of infectious diseases, but also to the adequate selection of antibiotics and the shortening of hospitalization.
 ...
PMID:[Advances in genetic diagnostics for respiratory tract infections]. 883 14

Relative bradycardia in infectious diseases is a poorly defined term. No exact and useful definition exists and the underlying mechanisms are unknown. Despite this, the term is often used in the literature and in clinical practice both as a clinical sign for an individual patient and as a characteristic feature of certain specific diseases. In this study a definition of relative bradycardia as a clinical sign in an individual patient and a definition of relative bradycardia as a characteristic feature of a specific disease were established based on a reference population comprising 673 patients with various infectious diseases. Relative bradycardia as a clinical sign in an individual patient held no predictive value regarding the likely type of infection. Relative bradycardia as a characteristic feature of specific disease was found for typhoid fever (P = 0.003), Legionnaire's disease (P = 0.005), and pneumonia caused by Chlamydia sp. (P = 0.0005), but not for mycoplasma pneumonia. It was not found for other pulmonary infections, infections caused by other Salmonella sp., other extracellular Gram-negative infections, or viral infections. Thus, relative bradycardia as a clinical sign has no predictive value for obtaining a tentative diagnosis, but relative bradycardia as a feature of specific disease is seen in typhoid fever, Legionnaire's disease, and pneumonia caused by Chlamydia sp. It seems that relative bradycardia as a feature of specific disease only occurs in diseases caused by organisms that are both Gram-negative and intracellular.
 ...
PMID:Relative bradycardia in infectious diseases. 1071 9

This article discusses four epidemics of fatal infectious diseases: a 1993 cluster of deaths among previously healthy persons in the southwestern United States that led to the identification of a new clinical syndrome, hantavirus pulmonary syndrome; the first epidemic of Ebola hemorrhagic fever identified in nearly two decades occurring in 1995 in Zaire, which resulted in 317 cases with a mortality rate of 77%; an outbreak of Legionnaires' disease among cruise ship passengers in 1994; and a 1989 cluster of illnesses among nonhuman primates in Reston, Virginia leading to the identification of a new strain of Ebola virus. In each outbreak, the public health emergency was recognized and reported by alert clinicians, and the control of disease was facilitated through rapid, coordinated responses involving multiple agencies. Such collaboration between clinical and public health entities and among various agencies will be increasingly needed as surveillance and diagnostic capabilities for emerging and reemerging infectious diseases are enhanced around the world.
 ...
PMID:Perspectives in fatal epidemics. 895 75

Legionella pneumophila has been relatively frequent pathogen of pneumonias worldwide. It causes 2-15% of pneumonias requiring hospitalization. It appears sporadically and in outbreaks, and frequently as hospital-acquired infection. The main aim of this study is to show the permanent presence of Legionnaires' disease in our country. In the 9-year period (1986-94), 42 patients were treated in the University Hospital of Infectious Diseases "Dr. Fran Mihaljevic" in Zagreb. The disease was diagnosed every year, and only one patient came from an outbreak, while all other cases of pneumonia were sporadic ones of pneumonia from the community. There were 40 males and only two women. Most of the patients (14) were in aged 30-39 yrs. There were six times more patients during summer and fall than in winter and spring time (36:6), and the highest number was in July (10). In 17 (40.5%) patients exposure to some potential sources of infection was recorded. Provocative factors i.e. underlying chronic diseases have been reported in 13 patients. There were 33 (78.6%) smokers, and 15 patients consumed greater quantities of alcoholic drinks. Legionnaires' disease affects also previously healthy persons as well as those without recognized provocative factors.
 ...
PMID:[Legionnaires' disease is not uncommon in Croatia]. 896 9

We describe the first known case of Legionella longbeachae infection in the Netherlands in a patient with myasthenia gravis. Infection with L. longbeachae relapsed after prolonged therapy with erythromycin. No environmental source of L. longbeachae could be traced.
 ...
PMID:Relapse of Legionella longbeachae infection in an immunocompromised patient. 897 93

International movement of individuals, populations, and products is one of the major factors associated with the emergence and reemergence of infectious diseases as the pace of global travel and commerce increases rapidly. Travel can be associated with disease emergence because (1) the disease arises in an area of heavy tourism, (2) tourists may be at heightened risk because of their activities, or (3) because they can act as vectors to transport the agent to new areas. Examples of recently recognized diseases with relationship to travel include HIV, Legionnaire's disease, cyclosporiasis, Vibrio cholerae O139 Bengal, hantavirus, and variant Creutzfeldt-Jacob disease. Reemerging diseases include dengue fever, malaria, cholera, schistosomiasis, leptospirosis, and viral hemorrhagic fevers. In addition, tuberculosis, drug-resistant shigellosis, and cholera have been major concerns in refugee and migrant populations. Because of the unique role of travel in emerging infections, efforts are underway to address this factor by agencies such as the CDC, WHO, the International Society of Travel Medicine, and the travel industry.
 ...
PMID:Emerging infectious diseases and travel medicine. 949 41

Legionnaires' disease is a modern environmental infectious disease. It stems from the capacity of the causative agent, Legionella, to multiply within amoebae in warm water and the use, during the 20th century, of devices that maintain water at warm temperatures and produce aerosols. When contaminated with Legionella, aerosols consisting of respirable droplets place the bacteria in juxtaposition with alveolar macrophages, which, as with amoebae, they may parasitize, resulting in illness in susceptible persons. The disease is much more common than previously appreciated with at least 13,000 cases estimated to occur per year in the United States, based on prospective studies. Two highly specific tests, urinary antigen detection and sputum culture, are available for diagnosis during illness. With 60% to 80% sensitivity, urinary antigen tests rapidly detect antigens of Legionella pneumophila serogroup 1, which are responsible for 70% of the cases of legionnaires' disease; results can be available within a few hours. Culture of sputum is 50% to 60% sensitive, but several days are required for growth, and many patients do not produce sputum. Serologic testing, although useful for epidemiologic studies when convalescent-phase antibody titers can be compared with acute-phase titers, is not helpful for clinical decision making because of the low positive predictive value of commercially available acute-phase serologic tests. Erythromycins, intravenous azithromycin, and levofloxacin are currently approved by the US Food and Drug Administration for treatment of legionnaires' disease. However, clarithromycin and several other fluoroquinolones are active against Legionella and may also provide effective therapy. Recent recommendations from the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee should be helpful in reducing nosocomial legionnaires' disease. Recommendations are in place or are being developed to minimize the risk of disease in a variety of other settings.
 ...
PMID:Legionnaires' disease: clinical, epidemiological, and public health perspectives. 964 85

Legionella pneumophila, the causative agent of legionnaires' disease, is a gram-negative pleomorphic bacillus and fastidious in its growth in artificial medium. These bacteria grow readily intracellularly, including growth in macrophages and other phagocytic cells. Humoral antibodies develop readily to these bacteria not only in infected patients, but also in persons who have had subclinical exposure. High-levels of serum antibodies may also occur in individuals who recover from infection. However, cell-mediated immunity based on lymphocytes reacting with the organisms and cytokines produced by such lymphocytes are important in resistance. Vaccines prepared from killed Legionella or their components readily induce cell-mediated immunity. Immune resistance to disease depends on lymphocyte-based immunity, activating cytokine formation, some of which activate macrophages to resist infection. Resistance to Legionella infection by experimental animals such as mice correlates with activation of macrophages, which can inhibit replication of the bacteria. Much recent experimental work has involved studies using inbred animals, including inbred mice genetically resistant to Legionella versus mice genetically susceptible. Detailed studies show that regulation of macrophage resistance versus susceptibility to infection is mediated by specific genetic mechanisms. Induction of cytokines by Legionella can activate immune cells, especially helper T cells. Th 1 type helper cells that produce type 1 class cytokines, such as interferon gamma and interleukin-2 (IL-2), are known to be important in cellular immunity to Legionella as well as to other opportunistic intracellular bacteria. In contrast, Th 2 type helper cells, which secrete type 2 class cytokines such as IL-4, IL-5, and IL-6, activate B lymphocytes to produce humoral antibodies important in resistance to extracellular bacteria which secrete toxins and extracellular factors as compared to intracellular bacteria such as Legionella. Although Legionella, similar to other ubiquitous opportunistic pathogens, can cause serious infection in immunocompromised individuals, these bacteria have many distinguishing characteristics, such as very rapid replication in macrophages from susceptible individuals. However, activated macrophages restrict the growth of these bacteria. Infection by Legionella, if recognized clinically, can be readily treated with appropriate antibiotics. Currently, many studies are in progress concerning the mechanism of pathogenicity and assessment of the molecular biologic mechanisms of protective immune responses to this bacterium, which causes serious infection in immunocompromised individuals.
 ...
PMID:Immunologic response and pathophysiology of Legionella infection. 964 87

Legionnaires' disease is a systemic infectious disease primarily involving the lungs, with multisystemic extrapulmonary manifestations. Any species of Legionella may cause legionnaires' disease in normal and compromised hosts. The clinical diagnosis of legionnaires' disease may be made on the basis of associated extrapulmonary clinical and laboratory findings. Although no single finding in legionnaires' disease is pathognomonic, the association of key extrapulmonary constitutes a typical pattern that is diagnostically characteristic. The syndromic approach based on a weighted point evaluation system described in the article gives physicians a system to arrive at a rapid presumptive clinical diagnosis of legionnaires' disease. Definitive diagnosis of legionnaires' disease is by direct fluorescent antibody testing of respiratory specimens, serological methods, Legionella urinary antigenuria, or culture.
 ...
PMID:Clinical features of legionnaires' disease. 964 89

In France the current consensus for the treatment of community-acquired pneumonia is based on the French Society for Infectious Diseases 1991 guidelines. In healthy adults without signs of severe disease, oral amoxicillin is recommended at the dose of 3 g per day for 8 to 10 days. This empirical choice is warranted by the prevalence of pneumococcal infections, found as causal agents in half to two-thirds of the bacteriologically proven cases. The 3 g dose is recommended due to the increasing risk of penicillin-resistant S. pneumoniae with MIC > 1 microgram/ml and exceptionally > 2 micrograms/ml. Clinical experience has shown that with a threshold at 2 micrograms/ml, 3 g of amoxicillin is a safe and sure choice. The duration is undoubtedly too long for most patients, but is a prudent measure due to the lack of clinical signs distinguishing between patent infection and its prolongation by inflammatory processes. Indiscriminate prescription of amoxicillin alone is however unacceptable as aminopenicillin is not effective against all microbial agents responsible for community-acquired pneumonia. The risk of selecting resistant strains is very real. Use of a large spectrum antibiotic could be indicated as first line treatment in patients with risk factors (underlying chronic disease, institutionalization, exposure to Gram negatives or S. aureus). For such patients, combination with a beta-lactamase inhibitor (coamoxiclav) or a cephalosporin with a MIC similar to that for penicillin G (cefpodoxime proxetil, cefuroxime axetil) could be recommended. In case of severe disease, Legionella pneumophila must be taken into consideration, implicating adjuction of a macrolide. Wide spectrum fluoroquinolones such as the soon to be available trovafloxacin offer a safe alternative, covering the main microorganisms responsible for community acquired pneumonia. Widespread use would however increase the risk of microbial resistance. In the current epidemiological situation in France, prescription of an aminopenicillin alone for alveolar community-acquired pneumonia in healthy adults remains the gold standard for first line therapy.
 ...
PMID:[Can aminopenicillin be prescribed as monotherapy in case of community-acquired pneumonia?]. 981 92


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