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Clinical Microbiology Reviews Jul 2002There is still a low level of clinical awareness regarding Legionnaires' disease 25 years after it was first detected. The causative agents, legionellae, are freshwater... (Review)
Review
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.
Topics: Animals; Humans; Legionella; Legionnaires' Disease; Research; Virulence
PubMed: 12097254
DOI: 10.1128/CMR.15.3.506-526.2002 -
Infectious Disease Clinics of North... Mar 2017Severe legionella pneumonia poses a diagnostic challenge and requires early intervention. Legionnaire's disease can have several presenting signs, symptoms, and... (Review)
Review
Severe legionella pneumonia poses a diagnostic challenge and requires early intervention. Legionnaire's disease can have several presenting signs, symptoms, and laboratory abnormalities that suggest that Legionella pneumophila is the pathogen, but none of these are sufficient to distinguish L pneumophila pneumonia from other respiratory pathogens. L pneumophila is primarily an intracellular pathogen and needs treatment with antibiotics that efficiently enter the intracellular space.
Topics: Anti-Bacterial Agents; Community-Acquired Infections; Diagnosis, Differential; Humans; Legionella pneumophila; Legionnaires' Disease; Pneumonia
PubMed: 28159171
DOI: 10.1016/j.idc.2016.10.009 -
Journal of Molecular Cell Biology Nov 2023Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires' disease.... (Review)
Review
Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires' disease. During infections, L. pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host. Notably, certain effector proteins mediate posttranslational modifications (PTMs), serving as useful approaches exploited by L. pneumophila to modify host proteins. Some effectors catalyze the addition of host protein PTMs, while others mediate the removal of PTMs from host proteins. In this review, we summarize L. pneumophila effector-mediated PTMs of host proteins, including phosphorylation, ubiquitination, glycosylation, AMPylation, phosphocholination, methylation, and ADP-ribosylation, as well as dephosphorylation, deubiquitination, deAMPylation, deADP-ribosylation, dephosphocholination, and delipidation. We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.
Topics: Humans; Legionella pneumophila; Legionnaires' Disease; Protein Processing, Post-Translational; Vacuoles; Ubiquitination
PubMed: 37156500
DOI: 10.1093/jmcb/mjad032 -
Archivum Immunologiae Et Therapiae... 2009The Legionellae are Gram-negative bacteria able to survive and replicate in a wide range of protozoan hosts in natural environments, but they also occur in man-made... (Review)
Review
The Legionellae are Gram-negative bacteria able to survive and replicate in a wide range of protozoan hosts in natural environments, but they also occur in man-made aquatic systems, which are the major source of infection. After transmission to humans via aerosols, Legionella spp. can cause pneumonia (Legionnaires' disease) or influenza-like respiratory infections (Pontiac fever). In children, Legionnaires' disease is uncommon and is mainly diagnosed in children with immunosuppression. The clinical picture of Legionella pneumonia does not allow differentiation from pneumonia caused by others pathogens. The key to diagnosis is performing appropriate microbiological testing. The clinical presentation and the natural course of Legionnaires' disease in children are not clear due to an insufficient number of samples, but morbidity and mortality caused by this infection are extremely high. The mortality rate for legionellosis depends on the promptness of an appropriate antibiotic therapy. Fluoroquinolones are the most efficacious drugs against Legionella. A combination of these drugs with macrolides seems to be promising in the treatment of immunosuppressed patients and individuals with severe legionellosis. Although all Legionella species are considered potentially pathogenic for humans, Legionella pneumophila is the etiological agent responsible for most reported cases of community-acquired and nosocomial legionellosis.
Topics: Aerosols; Animals; Diagnosis, Differential; Disease Transmission, Infectious; Drug Therapy, Combination; Fever; Fluoroquinolones; Humans; Legionellaceae; Legionnaires' Disease; Macrolides; Pneumonia; Virulence
PubMed: 19578813
DOI: 10.1007/s00005-009-0035-8 -
Seminars in Cell & Developmental Biology Dec 2022Legionella pneumophila, a Gram-negative intracellular bacterium, is one of the major causes of Legionnaires' disease, a specific type of atypical pneumonia. Despite... (Review)
Review
Legionella pneumophila, a Gram-negative intracellular bacterium, is one of the major causes of Legionnaires' disease, a specific type of atypical pneumonia. Despite intensive research efforts that elucidated many relevant structural, molecular and medical insights into Legionella's pathogenicity, Legionnaires' disease continues to present an ongoing public health concern. Legionella's virulence is based on its ability to simultaneously hijack multiple molecular pathways of the host cell to ensure its fast replication and dissemination. Legionella usurps the host ubiquitin system through multiple effector proteins, using the advantage of both conventional and unconventional (phosphoribosyl-linked) ubiquitination, thus providing optimal conditions for its replication. In this review, we summarize the current understanding of L. pneumophila from medical, biochemical and molecular perspectives. We describe the clinical disease presentation, its diagnostics and treatment, as well as host-pathogen interactions, with the emphasis on the ability of Legionella to target the host ubiquitin system upon infection. Furthermore, the interdisciplinary use of innovative technologies enables better insights into the pathogenesis of Legionnaires' disease and provides new opportunities for its treatment and prevention.
Topics: Humans; Bacterial Proteins; Host-Pathogen Interactions; Legionella pneumophila; Legionnaires' Disease; Ubiquitin
PubMed: 35177348
DOI: 10.1016/j.semcdb.2022.02.008 -
Epidemiology and Infection Jul 2023Over the past two decades, the incidence of legionellosis has been steadily increasing in the United States though there is noclear explanation for the main factors... (Review)
Review
Over the past two decades, the incidence of legionellosis has been steadily increasing in the United States though there is noclear explanation for the main factors driving the increase. While legionellosis is the leading cause of waterborne outbreaks in the US, most cases are sporadic and acquired in community settings where the environmental source is never identified. This scoping review aimed to summarise the drivers of infections in the USA and determine the magnitude of impact each potential driver may have. A total of 1,738 titles were screened, and 18 articles were identified that met the inclusion criteria. Strong evidence was found for precipitation as a major driver, and both temperature and relative humidity were found to be moderate drivers of incidence. Increased testing and improved diagnostic methods were classified as moderate drivers, and the ageing U.S. population was a minor driver of increasing incidence. Racial and socioeconomic inequities and water and housing infrastructure were found to be potential factors explaining the increasing incidence though they were largely understudied in the context of non-outbreak cases. Understanding the complex relationships between environmental, infrastructure, and population factors driving legionellosis incidence is important to optimise mitigation strategies and public policy.
Topics: United States; Humans; Incidence; Legionellosis; Disease Outbreaks; Temperature; Legionnaires' Disease
PubMed: 37503568
DOI: 10.1017/S0950268823001206 -
Przeglad Epidemiologiczny 2019The aim of this study is to assess the epidemiological situation of legionellosis in Poland in 2017 in comparison with previous years.
OBJECTIVE
The aim of this study is to assess the epidemiological situation of legionellosis in Poland in 2017 in comparison with previous years.
MATERIAL AND METHODS
The analysis is based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2017” and bulletins from previous years along with data from legionellosis case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH – NIH by Sanitary and Epidemiological Stations.
RESULTS
In Poland, both cases of Legionnaires’ disease (an acute form of infection with pneumonia) and Pontiac fever (a mild, influenza-like form of infection) are routinely reported to the surveillance system. In 2017, a total of 39 cases of legionellosis were registered, including 38 cases of Legionnaires’ disease and 1 case of Pontiac fever; the annual incidence rate 0.102 (per 100,000 population) has increased by almost 50 percent since previous year (0.070) and is almost three times higher than the median incidence (0.036) for 2011-2015. The infections were reported in fourteen voivodeships; only one voivodeship (Świętokrzyskie) did not register any case in last years. The incidence in men (0.129 per 100,000) was higher compared to women (0.076); the highest incidence (0.323) was noted in men aged 50-59. All reported cases were sporadic and were hospitalised. The Sanitary Inspection reported nine fatal cases – 6 women and 3 men. Thirty three cases were autochthonous including four cases linked with contaminated water systems in health-care settings. Six cases were associated with travels abroad (to Egypt, Albania, Italy and Crete).
SUMMARY AND CONCLUSIONS
Although in recent years number of reported cases continues to rise, the incidence of legionellosis in Poland remains one of the lowest in the entire EU. Also draws attention variation of incidence between provinces and a high mortality among reported cases. Our data suggest significant under-diagnosis of legionellosis. A priority remains to improve early diagnosis of Legionnaires’ disease in health care settings.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Female; Humans; Incidence; Legionellosis; Legionnaires' Disease; Male; Middle Aged; Poland; Registries; Young Adult
PubMed: 31385671
DOI: 10.32394/pe.73.26 -
The American Journal of Pathology Jun 1981
Review
Topics: Agglutination Tests; Antibody Specificity; Culture Media; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Legionella; Legionnaires' Disease; Risk; Serologic Tests; Tissue Preservation; United States
PubMed: 7015873
DOI: No ID Found -
Current Environmental Health Reports Mar 2022
Topics: Disease Outbreaks; Humans; Legionnaires' Disease
PubMed: 34003468
DOI: 10.1007/s40572-021-00319-3 -
Annals of Clinical Microbiology and... Aug 2017Legionnaires' disease is commonly diagnosed clinically using a urinary antigen test. The urinary antigen test is highly accurate for L. pneumophila serogroup 1, however... (Review)
Review
Legionnaires' disease is commonly diagnosed clinically using a urinary antigen test. The urinary antigen test is highly accurate for L. pneumophila serogroup 1, however other diagnostic tests should also be utilized in conjunction with the urinary antigen as many other Legionella species and serogroups are pathogenic. Culturing of patient specimens remains the gold standard for diagnosis of Legionnaires' disease. Selective media, BYCE with the addition of antibiotics, allows for a high sensitivity and specificity. Culturing can identify all species and serogroups of Legionella. A major benefit of culturing is that it provides the recovery of a patient isolate, which can be used to find an environmental match. Other diagnostic tests, including DFA and molecular tests such as PCR and LAMP, are useful tests to supplement culturing. Molecular tests provide much more rapid results in comparison to culture, however these tests should not be a primary diagnostic tool given their lower sensitivity and specificity in comparison to culturing. It is recommended that all laboratories develop the ability to culture patient specimens in-house with the selective media.
Topics: Antigens, Bacterial; Culture Media; Diagnostic Tests, Routine; Humans; Legionella pneumophila; Legionnaires' Disease; Polymerase Chain Reaction; Respiratory System; Sensitivity and Specificity
PubMed: 28851372
DOI: 10.1186/s12941-017-0229-6