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)

Despite being a well-known pathogen for immunocompromised patients, Legionella pneumophila has infrequently been described in persons with infection due to human immunodeficiency virus (HIV). Since 1986, we have identified eight cases of legionella pneumonia among seven HIV-infected persons enrolled in the HIV Natural History Study of the U.S. Air Force. The median CD4+ T cell count for these patients was 83/mm3; 50% of the cases occurred in persons for whom AIDS was previously diagnosed, and five of the cases were nosocomial. Six of the patients had coexistent pulmonary infections. None of the cases occurred among persons receiving prophylactic therapy with trimethoprim-sulfamethoxazole. Therapeutically, all patients appeared to respond well to standard antilegionella therapy or high doses of trimethoprim-sulfamethoxazole. Overall, these seven patients represent 1.7% of the patients with late-stage HIV infection (Walter Reed stage 5 or 6) in this cohort. L. pneumophila, although remaining an uncommon pathogen for HIV-infected patients, may produce serious disease in this population. HIV-infected persons should be considered at risk for legionnaires' disease, particularly in institutions where potable water supplies have become contaminated.
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PMID:Legionnaires' disease in human immunodeficiency virus-infected patients: eight cases and review. 852 92

A variety of immunologic tests were compared between human T-lymphotropic virus type I (HTLV-I) carriers and patients with adult T-cell leukemia/lymphoma (ATL). The mitogenic responses of the lymphocytes to concanavalin A and phytohemagglutinin were depressed in the ATL patients but not in the carriers, while the response to pokeweed mitogen in the carriers and ATL patients was depressed compared to the HTLV-I-seronegative controls. A positive tuberculin reaction in the carriers was as frequent as in the controls, but less frequent in the ATL patients. A marked inhibition of the intracellular multiplication of Legionella pneumophila was observed within the monocytes isolated from the carriers, but not in the ATL patients or the normal controls. These results indicate that the ATL patients have severe immunodeficiency, while the HTLV-I carriers have some activation of anti-microbial activity in monocytes although they are somewhat immunosuppressed.
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PMID:Differences in immune functions between human T-lymphotropic virus type I carriers and patients with adult T-cell leukemia/lymphoma. 881 Oct 55

The death rate from pneumonia in Singapore has increased steadily over the past decade. The emerging respiratory pathogens may have contributed to this increased mortality. New challenges have arisen from changes in the characteristics of the host and the susceptibilities of the various pathogens to antibiotics. There has been a 60-fold increase in the incidence of penicillin resistance in Streptococcus pneumoniae, the major pathogen for community-acquired pneumonia (CAP). Gram-negative bacilli are the major pathogens in severe CAP with Klebsiella pneumonia being the most frequently isolated organism. There has been a small increase in the number of cases of Legionnaire's disease and a marked increase in the incidence of melioidosis. While the overall incidence of tuberculosis has been unchanged, the number of non-residents with tuberculosis has doubled in the past 5 years. The rising prevalence of human immunodeficiency Virus infection is reflected in an increasing number of apparently healthy young men who present with CAP caused by Pneumocystis carinii. There is increasing resistance to antibiotics among gram-negative bacilli and Staphylococcus aureus, the dominant pathogens in hospital-acquired pneumonia. New strategies are urgently needed to prevent the emergence of pathogens in the hospital environment which may be resistant to all known antibiotics.
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PMID:Emerging pathogens for pneumonia in Singapore. 949 74

Viruses and bacteria in bronchoalveolar lavage fluids, protected specimen brush samples, and bronchial biopsies from 14 patients with primary hypogammaglobulinemia (11 patients with common variable immunodeficiency [CVID] and three patients with X-linked agammaglobulinemia [XLA]) were analyzed. At the time of the study, the patients had no signs of acute respiratory infections, and no antibiotics were administered. In addition to routine bacterial and viral cultures, polymerase chain reaction tests were used for the detection of adenovirus, cytomegalovirus (CMV), herpes simplex virus 1, enterovirus, rhinovirus, Borrelia burgdorferi, Chlamydia pneumoniae, Legionella spp., Mycoplasma pneumoniae, Pneumocystis carinii, and Ureaplasma urealyticum. Viruses (four adenoviruses, one CMV, and one rhinovirus) were detected in four of the 11 (36%) CVID patients. No viruses were found in the three patients with XLA or in 13 control patients. Bacteria from the lower respiratory tract were detected in nine of the 14 (64%) patients with hypogammaglobulinemia and three of the 13 (23%) control patients. Haemophilus influenzae was the most prevalent bacterium (43%) in the hypogammaglobulinemia patients. The study shows that patients with CVID harbor viral and bacterial infections in the lower respiratory tract, which may predispose to the development of changes in the respiratory tract.
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PMID:Viruses and bacteria in bronchial samples from patients with primary hypogammaglobulinemia. 1019 66

Pneumonia is one of the most frequent complications in acquired immunodeficiency syndrome-patients with Pneumocystis carinii as the leading cause. The true prevalence of atypical agents such as Chlamydia pneumoniae, C. trachomatis, Legionella pneumophila and Mycoplasma pneumoniae in this population of patients is unknown as the currently used method for diagnosing these agents is measurement of antibody levels. However, this method is of limited value in human immunodeficiency virus (HIV)-positive patients who may have a compromised antibody response. To evaluate the prevalence of Chlamydia spp., Legionella spp. and M. pneumoniae in HIV-infected patients with pulmonary disease, this retrospective study has applied inhibitor-controlled polymerase chain reaction analyses on 103 bronchoalveolar lavage (BAL) fluids representing 103 episodes of pneumonia in 83 HIV-positive patients. L. pneumophila was detected in 1% of the BAL fluids and M. pneumoniae was found as a coexisting pathogen in 2% of the samples. Chlamydia spp. could not be detected in any of the BAL fluids. By culture and staining methods 106 other microorganisms were detected with P. carinii and Streptococcus pneumoniae as the most frequently occurring. Pneumonia due to Chlamydia pneumoniae, Legionella pneumophila or Mycoplasma pneumoniae seems to be rare in Danish human immunodeficiency virus-infected patients, but might be considered as a possible cause in cases of treatment failure.
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PMID:Search for agents causing atypical pneumonia in HIV-positive patients by inhibitor-controlled PCR assays. 1083 44

Damage to local and systemic host defenses of the lung makes the immunocompromised patient vulnerable to inhaled microorganisms. When a pulmonary infiltrate occurs, the array of possibilities is very large including conventional and opportunistic agents. The type of underlying disease and its associated immunodeficiency allow a high degree of accurate pathogen prediction. Neutropenia is associated with Gram-negative bacilli pneumonia. Prolonged neutropenia increases the risk of invasive aspergillosis and other unusual mycotic agents. Cellular immunodeficiency is associated with intracellular microorganisms including Mycobacteria spp., Nocardia spp., Legionella spp., Rhodococcus equi, cytomegalovirus, Strongyloides stercoralis, Toxoplasma gondii, Histoplasma capsulatum, Coccidioides spp., Cryptococcus neoformans and Pneumocystis carinii, parasites such as Toxoplasma gondii and Strongyloides stercoralis, and virus such as cytomegalovirus, Herpes simplex or zoster, adenovirus, respiratory syncitial virus and measles. Humoral immunodeficiency predisposes to infection with encapsulated pathogens such as S. pneumoniae and Haemophilus influenzae. Chest computerized tomography scan and bronchoalveolar lavage are essential procedures for diagnosis. However, despite continuous progress in diagnostic methods, the specific etiology remains often unknown. Successful treatment depends on the type of pathogen, status of host defences and early adequate choice of antibiotic. Enhancement of host defences with growth factors and cytokines may decrease the incidence and improve the final outcome of respiratory infections in the immunocompromised host.
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PMID:[Respiratory infections during chemotherapy-induced aplasia]. 1142 9

In a prospective study, the etiology of community-acquired pneumonia (CAP) was investigated among consecutive patients admitted to an academic, urban public hospital in Seattle. The study population was uniquely young, was predominantly male, and had high rates of homelessness, cigarette smoking, alcoholism, injection drug use, and human immunodeficiency virus (HIV) infection. Leading causes of CAP among HIV-negative patients were aspiration, followed by Streptococcus pneumoniae, Legionella species, and Mycoplasma pneumoniae. Among HIV-positive patients, Pneumocystis carinii, Mycobacterium tuberculosis, S. pneumoniae, and M. pneumoniae were the most common etiologic agents. Severe CAP was associated with typical bacterial infections and aspiration pneumonia but not Legionella infection among HIV-negative patients and with Pseudomonas aeruginosa infections among HIV-positive patients. These findings emphasize the need to tailor empirical antibiotic therapy according to local patient populations and individual risk factors and highlight the importance of recognizing underlying HIV infection in patients who are hospitalized with CAP.
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PMID:The etiology of community-acquired pneumonia at an urban public hospital: influence of human immunodeficiency virus infection and initial severity of illness. 1144 51

Optimal therapy against Legionella infection is based on agents with a high intrinsic activity, an appropriate pharmacokinetic and pharmacodynamic profile (including the ability to penetrate phagocytic cells), a low incidence of adverse reactions and an advantageous cost-efficacy relationship. Newer macroazalides and fluoroquinolones are among the first-line therapies and in severe infections, particularly those occurring in immunocompromised patients, azithromycin and later fluoroquinolones are the agents of choice. Delay in the onset of adequate therapy is a key factor associated with a poor outcome. Thus, all patients with pneumonia associated with respiratory failure, shock or underlying disease causing severe immunodeficiency should initially receive an agent active against Legionella spp., at least while the aetiology remains unknown. Adjunctive measures improve outcome in critically ill patients. In intubated patients with delayed resolution, superinfection by Pseudomonas aeruginosa or co-infection caused by other pathogens should be excluded.
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PMID:Legionnaires' disease: a rational approach to therapy. 1266 78

Over the last decade, there was noted a large advancement of knowledge on living organisms and their products posing a potential occupational risk. Novel risk factors, often new to science, were identified, the role and significance of already known factors better comprehended, and occupational groups endangered by biological hazards more thoroughly recognized. Novel viruses and prions, emerging in different parts of the world, may pose a particular threat to health and life of health care workers, agriculture workers and veterinarians. A new coronavirus (SCoV) that evoked a rapid outbreak of disease described as severe acute respiratory syndrome (SARS) in the first half of 2003 may serve as an example. The disease was particularly common among health care workers. Previously discovered zoonotic viruses, Nipah virus in pigs and Hendra virus in horses, may be a cause of fatal encephalitis in animal farmers. Hantaviruses (Puumala, Hantaan, Sin Nombre and others) infecting field rodents may be a cause of hemorrhagic fever with renal syndrome (HFRS) or pulmonary syndrome (HPS) in farmers and laboratory workers. Prions responsible for inducing a zoonotic variant of Creutzfeldt-Jakob disease (vCJD) are considered to be a potential cause of work-related infections in agricultural and health care workers, however, this assumption has not as yet been supported by any conclusive evidence. In many countries, blood-borne occupational infections with hepatitis C virus (HCV) is the major epidemiological problem among health care workers, mostly because no vaccine against this virus has been produced to date. Vaccinations effectively restricted the number of occupational infections with hepatitis B virus (HBV), and work-related infections with human immunodeficiency virus (HIV) causing acquired immunodeficiency syndrome (AIDS) are very rare. Hazardous bioserosols, occurring in many work environments, pose an occupational health hazard of particular importance. Many new biological factors present in organic dusts that may induce work-related allergic and immunotoxic diseases among farmers and workers of the agricultural and wood industries have been identified. Droplet aerosols, which are generated from water, oils, oil-water emulsions and other liquids in various work environments, may contain infectious agents (Legionella spp.) as well as allergic and/or toxic agents. It has been shown that allergens and endotoxins produced by Gram-negative bacteria occurring in oil mist from metalworking fluids may cause occupational respiratory diseases in workers of the metallurgic industry.
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PMID:[Occupational bio hazards: current issues]. 1515 65

Fifty years ago, the age-old scourge of infectious disease was receding in the developed world in response to improved public health measures, while the advent of antibiotics, better vaccines, insecticides and improved surveillance held the promise of eradicating residual problems. By the late twentieth century, however, an increase in the emergence and re-emergence of infectious diseases was evident in many parts of the world. This upturn looms as the fourth major transition in human-microbe relationships since the advent of agriculture around 10,000 years ago. About 30 new diseases have been identified, including Legionnaires' disease, human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), hepatitis C, bovine spongiform encephalopathy (BSE)/variant Creutzfeldt-Jakob disease (vCJD), Nipah virus, several viral hemorrhagic fevers and, most recently, severe acute respiratory syndrome (SARS) and avian influenza. The emergence of these diseases, and resurgence of old ones like tuberculosis and cholera, reflects various changes in human ecology: rural-to-urban migration resulting in high-density peri-urban slums; increasing long-distance mobility and trade; the social disruption of war and conflict; changes in personal behavior; and, increasingly, human-induced global changes, including widespread forest clearance and climate change. Political ignorance, denial and obduracy (as with HIV/AIDS) further compound the risks. The use and misuse of medical technology also pose risks, such as drug-resistant microbes and contaminated equipment or biological medicines. A better understanding of the evolving social dynamics of emerging infectious diseases ought to help us to anticipate and hopefully ameliorate current and future risks.
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PMID:Social and environmental risk factors in the emergence of infectious diseases. 1557 34


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