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

Legionella pneumophila, the causative agent of Legionnaires' disease is able to live and multiply within macrophages as well as within protozoan organisms. Legionella strains inhibit phagosome-lysosome fusion and phagosome acidification. By using two different cell culture systems, one derived from human macrophages and the other from human embryo lung fibroblastic cells, it is demonstrated that Legionella strains lose their virulence following cultivation in the laboratory. In order to study the mechanisms involved in intracellular survival of Legionella a genomic library of strain Legionella pneumophila Philadelphia I was established in Escherichia coli K-12. By cosmid cloning technique we were able to clone five putative virulence factors, two of which exhibit hemolytic activities and three of which represent membrane-associated proteins of 19, 26 and 60 kilodalton. One of the hemolytic proteins, termed legiolysin, represents a new toxin which specifically lyses human erythrocytes. The other hemolysin exhibits proteolytic properties in addition and is cytolytic for Vero and CHO cells. Further studies will be necessary to determine the exact role of the cloned proteins in the pathogenesis of Legionella.
Infection 1991
PMID:Intracellular survival and expression of virulence determinants of Legionella pneumophila. 187 52

A prospective study of community acquired lower respiratory tract infection in the elderly was carried out over a 15-month period. During this time 127 consecutive admissions to two acute geriatric medical wards were studied. An aetiology was established in 77 (61%) of cases. Streptococcus pneumoniae was identified in 37% of patients. Haemophilus influenzae in 18% and Branhamella catarrhalis in 10%. Infection with Mycoplasma pneumoniae was found in only one episode and no cases of Legionella pneumophilia were diagnosed. A significant number of patients had multiple bacterial pathogens isolated: 18% of all bacterial pathogens isolated were ampicillin resistant. Fourteen patients died (11%). Lower respiratory tract infection is a frequent cause of hospital admission for those aged over 65 and is often regarded as a preterminal event. Adequately treated however, mortality is no higher than in the general population. Knowledge of the likely pathogens allows early and appropriate antibiotic therapy for these patients whether at home or on admission to hospital.
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PMID:Prospective hospital study of community acquired lower respiratory tract infection in the elderly. 190 44

Medical science has made tremendous strides in overcoming infectious diseases in the 20th century. Despite this, several epidemics of previously unrecognized diseases have occurred during the last 15 years. These diseases include Lyme disease, Legionnaires' disease, toxic shock syndrome, and AIDS. Examination of past epidemics, including the plague of Athens, the black death, syphilis, and influenza, suggests that the sudden occurrence of diseases that were previously unrecognized is not unusual. Analysis of the new infectious disease indicates that while all four appeared suddenly, isolated cases of the disease occurred before the actual epidemic. Further, all four new diseases were found to be due to agents or toxins that were not previously recognized. Epidemics due to new infectious diseases may arise by several mechanisms, including mutation of the pathogen to a virulent form and introduction of an infectious agent into a nonimmune population. Environmental and behavioral factors may play an important role, as illustrated by toxic shock syndrome, Legionnaires' disease, and AIDS. On the other hand, epidemic diseases tend to abate over time because of changes in the infecting pathogen and in the host. Hence, epidemics can be seen as cycles; new diseases will arise periodically, occasionally with a devastating outcome. With time the effects of these diseases on the population will ameliorate. The cycle will begin again when a new disease emerges.
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PMID:Plagues--what's past is present: thoughts on the origin and history of new infectious diseases. 192 88

Recent advance in molecular biology has enabled the specific and rapid diagnosis of the various infectious diseases. Though we commonly use the three major diagnostic procedure as isolation of the pathogen, direct detection of the pathogen and measurement of the immunological host reaction, DNA probe method would be the fourth major procedure in the clinical microbiology. The indication of the DNA probe method would be considered in the four cases as follows, 1. necessity of the special equipment to isolate the pathogen, 2. necessity of the long period to isolate the pathogen, 3. existence of the cross reaction among the pathogen and relative organisms in the immunological procedure, 4. existence of the difficulty to identify the species of the pathogen by the ordinary procedure. When we consider those indications, Legionnaires' disease might be one of the typical infectious disease to show the benefits of the DNA probe method in diagnosis. So far two types of DNA probe kits for Legionnaires' disease are available. One is the genus specific direct detection kit from the clinical specimens (Gen-probe), and the other is the microplate hybridization kit to identify each species of Legionella. The results of the evaluations of both kits showed the high specificity, rapidity and the clinical usefulness. In the next few years, various types of DNA probe kits might be newly developed and the contribution of those in the clinical microbiology would be much more than we expected.
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PMID:[Molecular diagnosis in respiratory infections]. 200 45

During the five-year period 1984-1988 we received 192 specimens from 180 patients infected with the human immunodeficiency virus (HIV) for investigation of Legionella infection. The majority of specimens were bronchoalveolar lavage (BAL) fluids (84%), but tracheal suctions and lung tissue from autopsies were also examined. The diagnostic methods used were a direct immunofluorescence assay (DFA) for the detection of Legionella antigen, and culture on buffered charcoal yeast extract (BCYE-alpha) media. All specimens were also examined for the presence of other bacterial lung pathogens, and all BAL specimens additionally for Pneumocystis carinii and mycobacteria. Legionellosis was not found to be common among HIV-infected patients, as only six specimens (3%) from six patients were found positive by DFA, and no specimens were culture-positive for Legionella species. Dual infection with Legionella and P. carinii occurred in two patients. Clinical data of the six patients are presented, and currently used methods for diagnosing legionellosis are discussed.
Infection
PMID:Legionellosis in patients with HIV infection. 207 6

We report on 20 cases of Legionnaires' Disease (LD) in heart transplant recipients during a two-year study. The overall frequency in this setting amounts thus to 17% (20/115). In contrast, the frequency of legionellosis in postoperative cardiac patients without immunosuppression was only 4.7% (4/84). Legionellosis was diagnosed by culture and/or antibody detection in ten (20) as well as by the detection of urinary antigens in all 20 patients. Only nine (20) patients developed pneumonia, whereas five patients presented with nodular infiltrates. The remaining six patients had moderate fever with no signs of lung infection. In contrast to the majority of patients with other underlying diseases, antigen shedding lasted for long periods in most transplant patients. In high risk patients the application of conventional diagnostic methods together with regular urinary antigen testings (i.e. twice a week) may be advantageous for the early diagnosis of Legionella infection.
Infection
PMID:Legionellosis in heart transplant recipients. 207 9

A case of community-acquired pneumonia caused by Legionella dumoffii in a patient with hairy cell leukemia is described. Diagnosis was confirmed by isolation by culture of sputum and broncho-alveolar lavage specimens, positive direct fluorescent antibody stains, and antibody seroconversion from 1:16 (acute) to 1:4096 (six months). The blue white autofluorescence of the L. dumoffii colonies when viewed under ultraviolet light was particularly useful in preliminary identification. The patient recovered from his pneumonia after administration of erythromycin and rifampin. Legionella have been shown to multiply in monocytes and cell-mediated immunity appears to be the primary mechanism of host defense in man. Hairy cell leukemia is characterized by monocyte dysfunction and such patients have a predilection for infection by microbes that are controlled by cell-mediated defenses. We review other cases of community-acquired L. dumoffii pneumonia as well as other cases of Legionella infection in patients with hairy cell leukemia.
Infection
PMID:Community-acquired pneumonia caused by Legionella dumoffii in a patient with hairy cell leukemia. 207 12

The Federal German DIN standard No. 19644 that has been enforced in West Germany since 1989 had to be revised in view of the fact that German legislation is expected to issue an ordinance on swimming pool and public bath water within the framework of the Federal Communicable Diseases Act; furthermore, the need for revision also arose from the solution of the hygienic problems of treatment and disinfection of warm whirlpool water, and from the necessity of modifying several now outdated regulations. It is the aim of public health legislation to prevent health risks of bathers and of attendant staff by Legionella pneumophila in all types of basins with additional water cycles and intake of air (aerosol formation); likewise, adverse health effects of side reaction products of the disinfectant chlorine (i. e. chloroamines and halogenated organic compounds, especially the trihalomethanes) must be avoided. Recent research has shown that these aims can be achieved by altering the mode of running and backwashing filters of all process combinations including those using ozone and introducing an additional absorption on powdered activated carbon, and the process combination of flocculation-filtration-chlorination. Improved treatment would be without effect if turnover rates could not be assessed reliably for basins of irregular geometry--as they are preferably used today--operated with additional water cycles involving intake of air. Lack of costly investigations prompts users to estimate turnover rates on the basis of experience collected with basins of square or rectangular dimensions.
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PMID:[Current status of bath water treatment techniques]. 214 49

The efficacy of intravenous ofloxacin therapy (200 mg 12-hourly) followed, when appropriate, by oral administration of the same dose was evaluated in an open multicentre trial involving 185 patients in 31 French hospitals. Dosage adjustment was made for patients in renal failure. Infection was hospital-acquired in 35 cases, 53 patients required admission to an intensive care unit. The infections comprised septicaemia (n = 56), pneumonia (n = 18), bronchitis (n = 10), urinary tract (n = 78), female pelvis (n = 8), bone and joint (n = 5), skin and soft tissues (n = 10). The causative pathogens were: Staphylococcus spp. (n = 23), Streptococcus spp. (n = 11), Escherichia coli (n = 85), Haemophilus influenzae (n = 9), Klebsiella, Enterobacter or Serratia spp. (n = 21), Salmonella spp. (n = 22), Chlamydia spp. (n = 3), Legionella spp. (n = 1), Mycoplasma pneumoniae (n = 1) and miscellaneous Gram-negative bacilli (n = 17). All were ofloxacin-susceptible. Mean duration of therapy was 8.06 ( +/- 2.6) days for the i.v. and 14.8 ( +/- 14.39) days for the oral preparation. Clinical cure was achieved in 173 patients (93.5%). It is concluded that iv ofloxacin is an effective treatment for a range of infections due to susceptible organisms.
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PMID:Efficacy of intravenous ofloxacin: a French multicentre trial in 185 patients. 228 86

A 63-year-old man was admitted to the respiratory intensive care unit for pneumonia. Fifteen years earlier, hairy cell leukemia had been diagnosed and the patient underwent splenectomy. A clinical suspicion of legionellosis, later confirmed by both serology and isolation of the microorganism, prompted initiation of high dose erythromycin intravenously. The patient steadily deteriorated and passed away eight days later. This is the first reported case of hairy cell leukemia in which the diagnosis of Legionella longbeachae sero-group 1 infection was based on both serology and isolation.
Infection
PMID:Legionella longbeachae pneumonia in a patient splenectomized for hairy-cell leukemia. 231 74


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