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

An increased incidence of sporadic or isolated cases of Legionnaires' disease has been identified. A 68-year-old male with lobar pneumonia is reported in detail and clinical aspects of 17 other cases from the literature are summarized. Important epidemiologic factors remain to be resolved, but a pattern of diagnostic criteria, clinical course, and therapeutic response similar to the epidemic incidence emerges from this collected series to guide the alert clinician.
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PMID:Case report. Legionnaires' disease. A review of clinical aspects of 18 sporadic cases. 46 48

In addition to several anomalous structures, other general forms of definitely rod-shaped microorganisms have been found by scanning and transmission electron microscopy in the lung tissue taken at autopsy from a patient who succumbed to confirmed Legionnaires' disease with extensive necrotizing lobar pneumonia. The microorganisms were greatly varied in size and shape. They were micrographed in the act of fission. These forms have been found to some extent throughout the tissue. No nickel was demonstrated, either in the lung tissue or in the microorganisms.
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PMID:Microorganisms seen by scanning and transmission electron microscopy in Legionnaires' disease from human lung. 49 5

The pathology and histology are reported of five Scots who died of severe pneumonic illnesses after holidays in Spain, three in 1973 and two in 1977. There is strong evidence in favour of all the deaths having been due to the newly discovered Legionnaires' disease (LD) agent. The agent (or its soluble antigen) has been visualised in sections of lung tissue by fluorescent-antibody tests in all cases, and the agent has been identified by the Dieterle silver staining method in small numbers in all cases. Serological testing was possible in three of the patients, and two had very high antibody titres against the LD agent. Apart from the extensive and severe nature of the pathological process there is no feature to distinguish pulmonary infection by this agent from that due to more commonly known bacteria capable of causing lobar pneumonia. The severity and extensive nature of the process is partly a reflection of neglect in seeking treatment until late in the infection, and partly a reflection, as revealed in retrospect, on the use of the wrong antibiotic combination during treatment. Erythromycin has been recommended by other workers as the drug of choice against the LD agent. Infection by this organism is not confined to the USA or to Spain and is indigenous also in the United Kingdom.
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PMID:Pathology of five Scottish deaths from pneumonic illnesses acquired in Spain due to Legionnaires' disease agent. 71 9

The Legionella bacillus is a relatively common pulmonary pathogen that has been responsible for a number of outbreaks of respiratory illness this century. Not until 1976, however, after exciting epidemiologic and microbiologic investigation, was the organism isolated and identified. Legionnaires' disease does not have a characteristic radiographic appearance, but certain features may alert the clinician to its presence. It often rapidly progresses to a lobar pneumonia that may not respond immediately to treatment. The radiographic findings lag behind clinical improvement, and radiographic resolution is prolonged. Organ transplantation patients often present with ill-defined, rounded, pleura-based opacities that may simulate pulmonary infarction and can cavitate.
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PMID:Legionnaires' disease. 186 Dec 75

The first proved outbreak of nosocomial Legionnaires' disease occurred in a psychiatric hospital in Washington D.C. in 1965, but the diagnosis was not established until determination of serum antibodies against Legionella pneumophila by the indirect fluorescent antibody (IFA) test was undertaken, using the bacterial antigen isolated from patients with Legionnaires' disease in the 1976 outbreak in Philadelphia. The second nosocomial outbreak of Legionnaires' disease occurred in three immunocompromised patients who received renal transplantation at the University of Kansas Medical Center and died of extensive lobar pneumonia in 1975. The direct fluorescent antibody (DFA) test revealed L. pneumophila in the lungs of all three patients after the Legionnaires' disease agent was identified. The lack of prospective surveys using sensitive diagnostic procedures by various types has limited our knowledge on the extent of the problem caused by legionella. In fact, nosocomial Legionnaires' disease is a worldwide problem, and control of this disease requires thorough cooperation of physicians, epidemiologists, microbiologists and expert engineers.
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PMID:Nosocomial Legionnaires' disease. 263 59

Following the discovery of Legionella pneumophila as the cause of an epidemic of pneumonia at an American Legion convention in Philadelphia, a group of related bacteria were recognized as additional human pathogens. This newly established bacterial genus, Legionella, includes the agents of Legionnaires' disease, Pittsburgh pneumonia, and several related infections. There are many similarities in the pathology of human infection caused by all the Legionella species. All produce a severe confluent lobular or lobar pneumonia, and abscess formation is not uncommon. A leukocytoclastic inflammatory infiltrate of neutrophils and macrophages, "septic" vasculitis of small blood vessels, coagulation necrosis, and focal septal disruption are characteristic but not diagnostic features. The inflammatory response is clearly that of a bacterial pneumonia with a necrotizing component, and does not resemble most mycoplasmal, chlamydial, or viral pneumonias. The bacteria can be demonstrated well by special stains. Acid fastness of Legionella micdadei, the cause of Pittsburgh pneumonia, is a helpful presumptive clue to diagnosis. The bacteria can be presumptively speciated in tissue by direct immunofluorescence. In addition, reliable recovery of the organisms on agar media now allows a specific diagnosis to be made. As a group, these infections are properly referred to as the Legionella pneumonias.
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PMID:The pathology of the Legionella pneumonias. A review of 74 cases and the literature. 616 29

The serial chest radiographic findings of 10 patients with Legionnaires' disease seen in Liverpool during 1980 are described. A unilateral lobar pneumonia was the commonest initial finding. Every lobe was involved, with the lower lobes being the most common. Pleural effusion was present in 30% of the cases. A comparison is made with previously reported series both in the United States and in England. Though no single feature is pathognomonic, the radiographic pattern may aid in early diagnosis.
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PMID:Analysis of the chest radiograph in Legionnaires' disease. 724 11

From March 1977 to December 1978, postmortem examination was performed at Wadsworth Veterans Administration Medical Center for 20 patients who had had nosocomially acquired Legionnaires' disease. Seventeen patients died during the acute illness due to Legionnaires' disease, and three patients died after clinical resolution of the acute process. The only consistent postmortem findings were limited to the lungs. Confluent bronchopneumonia, and less frequently lobar pneumonia, was present in most cases. Although a spectrum of microscopic pulmonary findings was observed, the characteristic histologic features of acute Legionnaires' disease were an extensive intra-alveolar exudation of macrophages and neutrophils in varying proportions, erythrocytes, and fibrin. Lysis of the inflammatory cells was frequently found. Areas of coagulative necrosis of the lung parenchyma and edematous thickening of the alveolar septa were typically seen. Microscopy of lung tissue from the three patients who died after clinical resolution of the acute process revealed organized pneumonia, with patchy organization of the intra-alveolar exudate and focal obliteration of the alveolar septal framework. Associated postmortem findings were fibrinous endocarditis in one case and hemorrhagic infarction of the adrenal glands in two cases. Electron-microscopic examination of the lungs revealed as many as 23 separate bacillary profiles within a single macrophage. Septate binary fission or spore-like structures were not observed.
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PMID:Legionnaires' disease. Postmortem pathologic findings of 20 cases. 736 72

We reviewed chest roentgenograms from 17 persons with confirmed Legionnaires' disease. None of the cases was associated with known outbreaks. Pulmonary infiltrates, usually extensive, were present in all cases. The predominant radiological pattern of both on initial roentgenograms and those from the peak of illness was distal air space disease, usually in a segmental or lobar distribution. The lower lobes were involved most frequently. Pleural effusion and volume loss were infrequent. Radiological findings progressed rapidly and often cleared rapidly, although slow clearing was also seen in some cases. Legionnaires' disease should be included in the radiological differential diagnosis of segmental or lobar pneumonia.
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PMID:The chest roentgenogram in sporadic cases of Legionnaires' disease. 745 87

The bacterium Legionella pneumophila is the principal etiologic agent of Legionnaires' disease, a form of lobar pneumonia. Ubiquitous in aquatic environments, the gram-negative Legionella organism is a facultative, intracellular parasite of protozoa. The pathogenesis of legionellosis is largely due to the ability of L. pneumophila to invade and grow within alveolar macrophages, and it is widely believed that this ability results from a prior adaptation to intracellular niches in nature. Indeed, intracellular legionellae display a remarkable capacity to avoid endosomal and lysosomal bactericidal activities and to establish a unique replicative phagosome. In recent years, much progress has been made toward identifying the bacterial factors that promote intracellular infection and virulence. Surface structures that enhance infection include LPS, flagella, type IV pili, an outer membrane porin, and the Mip propyl-proline isomerase. Both type II and type IV protein secretion systems are critical for L. pneumophila pathogenesis. Whereas the type II (Lsp) system secretes a collection of degradative enzymes, the type IV (Dot/Icm) system likely exports effector proteins that are especially critical for trafficking of the Legionella phagosome. In addition to facilitating pilus formation and type II secretion, the inner membrane prepilin peptidase (PilD) of L. pneumophila appears to mediate a third, potentially novel pathway that is operative in the mammalian host. Periplasmic and cytosolic infectivity determinants include a catalase-peroxidase and the HtrA and Hsp60 stress-response proteins. The stationary phase response and the iron acquisition functions of L. pneumophila also play key roles in pathogenesis, as do a number of other loci, including the pts, mil and enh genes.
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PMID:Pathogenicity of Legionella pneumophila. 1172 17


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