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

There is still a low level of clinical awareness regarding Legionnaires' disease 25 years after it was first detected. The causative agents, legionellae, are freshwater bacteria with a fascinating ecology. These bacteria are intracellular pathogens of freshwater protozoa and utilize a similar mechanism to infect human phagocytic cells. There have been major advances in delineating the pathogenesis of legionellae through the identification of genes which allow the organism to bypass the endocytic pathways of both protozoan and human cells. Other bacteria that may share this novel infectious process are Coxiella burnetti and Brucella spp. More than 40 species and numerous serogroups of legionellae have been identified. Most diagnostic tests are directed at the species that causes most of the reported human cases of legionellosis, L. pneumophila serogroup 1. For this reason, information on the incidence of human respiratory disease attributable to other species and serogroups of legionellae is lacking. Improvements in diagnostic tests such as the urine antigen assay have inadvertently caused a decrease in the use of culture to detect infection, resulting in incomplete surveillance for legionellosis. Large, focal outbreaks of Legionnaires' disease continue to occur worldwide, and there is a critical need for surveillance for travel-related legionellosis in the United States. There is optimism that newly developed guidelines and water treatment practices can greatly reduce the incidence of this preventable illness.
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PMID:Legionella and Legionnaires' disease: 25 years of investigation. 1209 54

Patients hospitalized with community acquired pneumonia were studied prospectively in two hospitals located in the surroundings of Buenos Aires city. Fifty two patients from General Hospital Manuel Belgrano (HMB) were included from March 1998 to February 1999 and 23 patients from Hospital Dr A. Cetrangolo (HCET) for respiratory disease, were included from June 2000 to May 2001. Patients with lung tuberculosis, lung neoplasia and HIV infection were excluded. Clinical background, signs and symptoms were recorded. Microbiological examinations performed included bacteria, respiratory viruses and mycobacteria. Studies for "atypical" bacteria (Chlamydia spp., Coxiella burnetii, Mycoplasma pneumoniae and Legionella spp.) were carried out by serological methods. No differences in age and gender were observed between both groups. Most frequently observed comorbidities in the HMB group included COPD, diabetes and cardiac failure while in the HCET group these were COPD, asthma and lung fibrosis. Etiology was established in 48% and 65.2% of the patients in the first and second group, respectively. Most frequent agents were Mycoplasma pneumoniae, Streptococcus pneumoniae, influenza A and Legionella spp.; the last one was detected in 12% of the patients. Most of these patients were from HMB and presented a good outcome. Mortality was similar in both groups (13.3%). In the HBM group it was related to the presence of comorbidities in 7 out of 8 cases, and in the HCET group it was a consequence of the worsening of their chronic respiratory failure.
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PMID:[Community-acquired pneumonia in patients in 2 hospital populations]. 1267 53

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

A prospective cohort study of adult patients hospitalized due to community-acquired pneumonia was carried out for 1 year in a Brazilian university general hospital to detect the incidence of community-acquired pneumonia by Legionella pneumophila serogroups 1-6. During a whole year, a total of 645 consecutive patients who were hospitalized due to a initial presumptive diagnosis of respiratory disease by ICD-10 (J00-J99), excluding upper respiratory diseases, were screened to detect the patients with community-acquired pneumonia. Fifty-nine consecutive patients hospitalized due to community-acquired pneumonia between July 19, 2000 and July 18, 2001, were included in the study. They had determinations of serum antibodies to L. pneumophila serogroups 1-6 by indirect immunofluorescence antibody test at the Infectious Diseases Laboratory of University of Louisville (KY, USA) and urinary antigen tests for L. pneumophila serogroup 1. Three patients had community-acquired pneumonia by L. pneumophila serogroups 1-6, two patients being diagnosed by seroconversion and positive urinary antigen tests; the other had negative serologies but strongly positive urinary antigen test. The incidence of community-acquired pneumonia by L. pneumophila serogroups 1-6 in our hospital was 5.1%.
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PMID:Community-acquired pneumonia by Legionella pneumophila serogroups 1-6 in Brazil. 1595 Jan 37

This article provides an overview of pneumonia as a high-incidence respiratory disease of varying severity in the 21st century. Many cases are mild to moderate and patients are successfully treated with antibiotics at home and with no lasting damage to the lungs. Vaccinations for influenza and, more recently, pneumococcal infections are becoming widely available for vulnerable groups of people, which will help to reduce the incidence of these diseases. However, pneumonia causes death in more severe cases with atypical forms such as Legionnaires' disease and severe acute respiratory syndrome (SARS) causing fatal outbreaks.
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PMID:Pneumonia: classification, diagnosis and nursing management. 1601 5

In three male patients with lower respiratory disease, aged 51, 32 and 63 years, Legionnaires' disease was diagnosed by urinary antigen test and culture of the respiratory-tract fluid. In the second patient, the bronchoalveolar fluid also contained Streptococcus pneumoniae and Haemophilus influenzae. All three patients recovered after treatment with azithromycin in the first, cefotaxime, vancomycin and levofloxacin in the second, and erythromycin and ciprofloxacin in the third, respectively. Legionella pneumophila pneumonia is clinically not clearly distinct from other pneumonias and has a high mortality rate when not treated with the proper antibiotics. For that reason, adequate and swift diagnosis is of great importance. The urinary antigen test meets both of these criteria. Still, it is advisable to use culture and serology as well if Legionnaires' disease is suspected in a patient, since the urinary antigen test has limitations. In addition, patient isolates are ofepidemiological importance for public health. By comparing available patient isolates with Legionella strains from water sources, it is possible to identify sources of infection. In 2002, based on this principle, a project was started in The Netherlands aimed at identifying sources of infection, thereby preventing outbreaks of Legionnaires' disease by swift elimination of the source. Since the start of the project, 29 sources have been identified. In the cases described above these were a sauna, a cooling tower and a caravan, respectively. In suspected cases, respiratory-tract fluid must be collected to make possible such a source investigation.
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PMID:[Three patients with pneumonia due to Legionella associated with a sauna, a cooling tower and a caravan in The Netherlands]. 1617 Nov 14

Recreational waters are a source of infection by several microorganisms causing acute gastrointestinal, cutaneous and respiratory illnesses. Cryptosporidium, noroviruses and enteropathogenic Escherichia coli strains are the most important causes of diarrhea, while Pseudomonas and Staphylococcus aureus are the main causes of cutaneous infections, and Legionella is the major cause of acute lower respiratory disease. Approximately 90% of outbreaks occur in treated recreational waters (swimming pools, spas and recreational parks), while the remaining 10% arise from natural waters used for leisure (bathing in rivers, beaches, etc). In spas, most infections are caused by thermophilic bacteria, such as Pseudomonas and Legionella, since overgrowth of these bacteria is facilitated by the direct effect of temperature and, indirectly, by the evaporation of the disinfectant. Outbreaks related to recreational waters usually reflect deficient control of the system: a low level of disinfectant, or the use of an inappropriate disinfectant, insufficient maintenance and cleaning of the installation, higher than recommended usage, and failure of the disinfectant dosage system. The correct design, maintenance and use of these facilities drastically lower the risk of infections from recreational waters. Thus, other key actions to minimize this risk are the existence of, and compliance with, regulatory rules, as well as educational campaigns on good hygiene practices directed at users. Rapid etiologic diagnosis of affected patients, together with an epidemiological survey and detection of the pathogen implicated in water samples are the keys to outbreak control.
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PMID:[Infections related to recreational waters]. 1910 Jan 65

This study established an experimental model of replicative Legionella longbeachae infection in A/J mice. The animals were infected by intratracheal inoculation of 10(3)-10(9) c.f.u. L. longbeachae serogroup 1 (USA clinical isolates D4968, D4969 and D4973). The inocula of 10(9), 10(8), 10(7) and 10(6) c.f.u. of all tested L. longbeachae serogroup 1 isolates were lethal for A/J mice. Inoculation of 10(5) c.f.u. L. longbeachae caused death in 90 % of the animals within 5 days, whilst inoculation of 10(4) c.f.u. caused sporadic death of mice. All animals that received 10(3) c.f.u. bacteria developed acute lower respiratory disease, but were able to clear Legionella from the lungs within 3 weeks. The kinetics of bacterial growth in the lungs was independent of inoculum size and reached a growth peak about 3 logarithms above the initial inoculum at 72 h after inoculation. The most prominent histological changes in the lungs were observed at 48-72 h after inoculation in the form of a focal, neutrophil-dominant, peribronchiolar infiltration. The inflammatory process did not progress towards the interstitial or alveolar spaces. Immunohistological analyses revealed L. longbeachae serogroup 1 during the early phase of infection near the bronchiolar epithelia and later co-localized with inflammatory cells. BALB/c and C57BL/6 mice strains were also susceptible to infection with all L. longbeachae serogroup 1 strains tested and very similar changes were observed in the lungs of infected animals. These results underline the infection potential of L. longbeachae serogroup 1, which is associated with high morbidity and lethality in mice.
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PMID:Experimental Legionella longbeachae infection in intratracheally inoculated mice. 1942 47

Although the majority of cases of Legionnaires' disease (LD) are caused by Legionella pneumophila, an increasing number of other Legionella species have been reported to cause human disease. There are no clinical presentations unique to LD and hence accurate laboratory tests are required for early diagnosis. Therefore, we designed a real-time PCR assay that targets the 23S-5S rRNA intergenic spacer region (23S-5S PCR) and allows for detection of all Legionella species and discrimination of L. pneumophila from other Legionella species. In total, 271 isolates representing 50 Legionella species were tested and the assay was validated using 39 culture-positive and 110 culture-negative patient specimens collected between 1989 and 2006. PCR-positive results were obtained with all 39 culture-positive samples (100% sensitivity). Specimens that tested positive according to 23S-5S PCR, but were culture-negative, were further analysed by DNA sequencing of the amplicon or the macrophage infectivity potentiator (mip) gene. In addition to L. pneumophila, Legionella longbeachae, Legionella cincinnatiensis and Legionella micdadei were identified in the specimens. The assay showed a 7-log dynamic range displaying a sensitivity of 7.5 CFU/mL or three genome equivalents per reaction. Sixty-one specimens containing viruses or bacteria other than Legionellae were negative according to 23S-5S PCR, demonstrating its specificity. Use of this assay should contribute to the earlier detection of respiratory disease caused by Legionella species, as well as to increased rates of detection.
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PMID:Dual detection of Legionella pneumophila and Legionella species by real-time PCR targeting the 23S-5S rRNA gene spacer region. 1943 41

In May 2008, a report of two workers from the same construction equipment manufacturing plant who were admitted to hospital with Legionnaires disease confirmed by urine antigen prompted an outbreak investigation. Both cases were middle aged men, smokers, and with no travel, leisure or other common community exposure to Legionella sources. There were no wet cooling towers at the plant or in the surrounding area. No increase in respiratory disease or worker absenteeism occurred at the plant during the preceding month. Wider case ascertainment including alerts to hospitals and medical practitioners yielded no further cases. The environmental investigation (and sampling of water systems for Legionella) identified a Legionella pneumophila serogroup1 (Mab 2b) count of >3.0x10(4)cfu/l in water samples from an aqueous metal pre-treatment tunnel, which generates profuse water aerosol. Drainage, cleaning and biocide treatment using thiazalone eliminated Legionella from the system.
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PMID:Legionnaires' disease cluster linked to a metal product aqueous pre-treatment process, Staffordshire, England, May 2008. 1982 19


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