Subclinical<i>Legionella</i>Infection in Workers Near the Source of a Large Outbreak of Legionnaires Disease

Boshuizen, Hendriek C.; Neppelenbroek, S E; Vliet, Hans van; Schellekens, J. F. P.; Boer, Jeroen W. Den; Peeters, Marcel; Spaendonck, M. A. E. Conyn-Van

doi:10.1086/322049

Cited by 65 publications

(65 citation statements)

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“…These results resemble those of Maesaki et al (9) who reported an outbreak of Legionella pneumonia in a nursing home. Attack rates in outbreaks of Legionella pneumonia are usually low [0.1%-5% of exposed persons develop clinical symptoms (10)] and the development of pneumonia was seen in only one person here. The low attack rate may be due to host factors or differences in exposure (10).…”

Section: Discussionmentioning

confidence: 92%

“…Attack rates in outbreaks of Legionella pneumonia are usually low [0.1%-5% of exposed persons develop clinical symptoms (10)] and the development of pneumonia was seen in only one person here. The low attack rate may be due to host factors or differences in exposure (10). However, especially in places such as nursing homes where many people are susceptible to microbes, strict management practices to reduce microbial contamination of 24-hour bath water are needed to prevent Legionella pneumonia which can sometimes cause severe disease (11).…”

Section: Discussionmentioning

confidence: 92%

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Legionella Pneumonia due to Exposure to 24-hour Bath Water Contaminated by Legionella pneumophila Serogroup-5

Mineshita¹,

Nakamori²,

Seida³

et al. 2005

Intern. Med.

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A 79-year-old man was admitted to hospital from his nursing home for treatment of pneumonia, but died 7 days after admission. Legionella pneumonia was diagnosed after isolation of Legionella pneumophila serogroup-5 from sputum culture. The environment of the nursing home was investigated; only water specimens from the 24-hour bath were positive by culture for Legionella pneumophila serogroup-5. Subsequent analysis by pulsed-field gel electrophoresis revealed an identical pattern in isolates from both sputum culture and 24 hour bath water culture. Among 123 inpatients and staff of the nursing home, 17 were found to be seropositive for Legionella pneumophila serogroup-5.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 92%

Legionella Pneumonia due to Exposure to 24-hour Bath Water Contaminated by Legionella pneumophila Serogroup-5

Mineshita¹,

Nakamori²,

Seida³

et al. 2005

Intern. Med.

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“…A nationwide alert for LD cases ensured optimal case finding, thereby decreasing patient selection bias. Furthermore, the conditions for a gold standard were favorable: two national reference laboratories performed all microbiological tests, and Dutch reference titers were calculated using the distribution of antibodies against L. pneumophila serogroup 1 in a large sample from a national serum bank (4). In addition, all available clinical data for the LD patients in this outbreak were recorded centrally.…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of Three Urinary Antigen Tests Associated with Clinical Severity in a Large Outbreak of Legionnaires' Disease in The Netherlands

et al. 2002

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In 1999 an outbreak involving 188 patients with Legionnaires' disease (LD) occurred among visitors to a flower show in the Netherlands. Two enzyme immunoassays (Binax and Biotest) and one immunochromatographic assay (Binax NOW) were tested, using urine samples from LD patients from the 1999 outbreak. Sensitivity was calculated using positive culture and/or seroconversion as the "gold standard" in outbreakrelated patients with radiographically confirmed pneumonia who fulfilled the epidemiological critera. The Binax EIA, Biotest EIA, and Binax NOW assay showed overall sensitivities of 69, 71, and 72%, respectively. When the tests were performed with concentrated urine samples, the overall sensitivities increased to 79, 74, and 81%, respectively. Using multiple logistic regression analysis with backward elimination, a statistically significant association was found between clinical severity and test sensitivity for all tests. For patients with mild LD, the test sensitivities ranged from 40 to 53%, whereas for patients with severe LD who needed immediate special medical care, the sensitivities reached 88 to 100%. These findings have major implications for the diagnostic process in patients with mild pneumonia and suggest that patients with mild pneumonia may go underdiagnosed if urine antigen tests alone are used. Legionnaires' disease (LD) is an acute pneumonia caused byLegionella, a rod-shaped gram-negative bacillus ubiquitous in (man-made) aquatic reservoirs. Currently 43 Legionella species and 65 serogroups have been described. In the United States, over 90% of Legionnaires' disease cases are caused by Legionella pneumophila, of which 70% of strains belong to serogroup type 1 (16). Legionella spp. are responsible for 1 to 5% of cases of community-acquired pneumonia (CAP) (5). Clinically and radiographically, LD cannot be distinguished from pneumonias caused by other microbial pathogens. Because of the high mortality rate in patients with LD requiring hospitalization, early diagnosis to enable adequate antimicrobial treatment is potentially life-saving. Diagnosis of LD in patients with symptomatic pneumonia is based on culture, serologic testing, or antigen detection in urine. Isolation of Legionella from respiratory secretions is not a very sensitive diagnostic test (25 to 75% sensitivity) (15) and has the disadvantage of delay, because a positive result is not available until at least 3 days of incubation. Seroconversion is a diagnostic test with a high sensitivity and a high (serogroup-dependant) specificity, but it is of limited clinical value since it may take up to 9 weeks for patients to develop detectable antibodies (10, 13).In contrast to the other tests mentioned above, urinary antigen tests combine reasonable sensitivity and high specificity with rapid results. The reported sensitivities of both enzyme immunoassay (EIA) and immunochromatographic test (ICT) show great variation: 50 to 90% (3,7,8,19). These variations may be explained by differences in patient characteristics, the serogroup with which th...

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“…Robust immune response of a healthy individual normally is sufficient to clear L. pneumophila, making legionellosis largely a disease of people with a compromised immune system (20). Experiments with the mouse model have revealed that immune cells are able to recognize classic L. pneumophila PAMP molecules such as lipopolysaccharide, flagellin, and nucleic acids to mount a robust response (21).…”

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confidence: 99%

Induction of Rapid Cell Death by an Environmental Isolate of Legionella pneumophila in Mouse Macrophages

Tao

Zhu

et al. 2013

Infect Immun

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c Legionella pneumophila, the etiological agent for Legionnaires' disease, is ubiquitous in the aqueous environment, where it replicates as an intracellular parasite of free-living protozoa. Our understanding of L. pneumophila pathogenicity is obtained mostly from study of derivatives of several clinical isolates, which employ almost identical virulent determinants to exploit host functions. To determine whether environmental L. pneumophila isolates interact similarly with the model host systems, we analyzed intracellular replication of several recently isolated such strains and found that these strains cannot productively grow in bone marrow-derived macrophages of A/J mice, which are permissive for all examined laboratory strains. By focusing on one strain called LPE509, we found that its deficiency in intracellular replication in primary A/J macrophages is not caused by the lack of important pathogenic determinants because this strain replicates proficiently in two protozoan hosts and the human macrophage U937 cell. We also found that in the early phase of infection, the trafficking of this strain in A/J macrophages is similar to that of JR32, a derivative of strain Philadelphia 1. Furthermore, infection of these cells by LPE509 caused extensive cell death in a process that requires the Dot/Icm type IV secretion system. Finally, we showed that the cell death is caused neither by the activation of the NAIP5/NLRC4 inflammasome nor by the recently described caspase 11-dependent pathway. Our results revealed that some environmental L. pneumophila strains are unable to overcome the defense conferred by primary macrophages from mice known to be permissive for laboratory L. pneumophila strains. These results also suggest the existence of a host immune surveillance mechanism differing from those currently known in responding to L. pneumophila infection.

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SubclinicalLegionellaInfection in Workers Near the Source of a Large Outbreak of Legionnaires Disease

Cited by 65 publications

References 14 publications

Legionella Pneumonia due to Exposure to 24-hour Bath Water Contaminated by Legionella pneumophila Serogroup-5

Legionella Pneumonia due to Exposure to 24-hour Bath Water Contaminated by Legionella pneumophila Serogroup-5

Sensitivity of Three Urinary Antigen Tests Associated with Clinical Severity in a Large Outbreak of Legionnaires' Disease in The Netherlands

Induction of Rapid Cell Death by an Environmental Isolate of Legionella pneumophila in Mouse Macrophages

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