Legionellosis, Legionaires' disease or Legionella[note 1] is an infectious disease caused by an aerobic Gram-negative bacteria, of the genus Legionella.
The infection can manifest itself in two different ways:[1].
About 90% of legionellosis cases are caused by Legionella pneumophila, a ubiquitous aquatic organism that thrives at temperatures between 25°C (77.0°F) and 45°C (113°F), with an optimum of 35°C (95.0°F).
Legionnaires' disease epidemics are usually the focus of media attention due to their frequent links to specific facilities. However, this disease generally appears as an isolated case, not associated with any officially recognized outbreak. The epidemic usually appears in the summer or early fall, but cases can occur throughout the year.
Some infected people may have mild symptoms or no symptoms at all. About 5% to 30% of people who suffer from legionellosis die, especially if antibiotic treatments have been delayed.[2] It is estimated that 8,000 to 18,000 people suffer from legionellosis in the US each year.
History
Legionnaires' disease or legionellosis acquired its name in 1976, when an epidemic outbreak of pneumonia appeared among participants at the 58th convention of the American Legion in Philadelphia (USA).[3][1].
On January 18, 1977, scientists identified a previously unknown bacteria as the cause of the mysterious Legionnaires' disease infection. It was a bacteria of the genus "Genus (biology)") Legionella of which Legionella pneumophila stands out.
Epidemiology
Legionella is frequently found in natural bodies of water, however it is urban water systems that represent the main source of disease for human beings. Legionella reproduces in biofilms within water systems and is relatively resistant to chlorine levels in drinking water. The developments of aerosol storage and generation systems such as cooling towers, spas, outdoor and indoor water fountains, showers, and misters in grocery stores have increased its transmission.[1].
Legionella Risk
Introduction
Legionellosis, Legionaires' disease or Legionella[note 1] is an infectious disease caused by an aerobic Gram-negative bacteria, of the genus Legionella.
The infection can manifest itself in two different ways:[1].
About 90% of legionellosis cases are caused by Legionella pneumophila, a ubiquitous aquatic organism that thrives at temperatures between 25°C (77.0°F) and 45°C (113°F), with an optimum of 35°C (95.0°F).
Legionnaires' disease epidemics are usually the focus of media attention due to their frequent links to specific facilities. However, this disease generally appears as an isolated case, not associated with any officially recognized outbreak. The epidemic usually appears in the summer or early fall, but cases can occur throughout the year.
Some infected people may have mild symptoms or no symptoms at all. About 5% to 30% of people who suffer from legionellosis die, especially if antibiotic treatments have been delayed.[2] It is estimated that 8,000 to 18,000 people suffer from legionellosis in the US each year.
History
Legionnaires' disease or legionellosis acquired its name in 1976, when an epidemic outbreak of pneumonia appeared among participants at the 58th convention of the American Legion in Philadelphia (USA).[3][1].
On January 18, 1977, scientists identified a previously unknown bacteria as the cause of the mysterious Legionnaires' disease infection. It was a bacteria of the genus "Genus (biology)") Legionella of which Legionella pneumophila stands out.
Epidemiology
Legionella is frequently found in natural bodies of water, however it is urban water systems that represent the main source of disease for human beings. reproduces in biofilms within water systems and is relatively resistant to chlorine levels in drinking water. The developments of aerosol storage and generation systems such as cooling towers, spas, outdoor and indoor water fountains, showers, and misters in grocery stores have increased its transmission.[1].
People of any age can develop legionellosis, but the disease more frequently affects men over 45 years of age, smokers and immunocompromised (either due to diseases such as cancer, diabetes or AIDS; dialysed or taking medicines that suppress the immune system.[1].
Legionnaires' disease outbreaks occur when people have inhaled aerosols containing water (for example, from air conditioning cooling water towers, fountains, irrigation sprinklers, showers) contaminated with Legionella bacteria. People can be exposed to these aerosols at home, workplaces, hospitals, and public places. Legionnaires' disease is not transmitted from person to person and there is no evidence of infection of the disease in car air conditioners or home air conditioning units.
The largest outbreak of legionellosis in history took place in July 2001 in Murcia, Spain, with 6 deaths and more than 600 affected. The focus was located in several ventilation towers: in El Corte Inglés, in the Ministries of Health and Agriculture, in the San Esteban Palace and at the Caja Murcia headquarters.[4].
Another outbreak took place during the autumn of 2014 in Catalonia, Spain, with 10 deaths (six in Sabadell and four in Ripollet) and more than forty people infected, four of them hospitalized and one very serious. The focus of this outbreak has not been clarified.[5].
Another outbreak emerged in May 2018 in the city of Úbeda, Jaén, Andalusia with 4 people admitted to the ICU, currently unresolved.
The newest outbreak to date is in the Province of Tucumán, Argentina, with 5 deaths. The focus was on Luz Medica, a private clinic. Until September 4, 2022, there is a lack of confirmatory evidence that it really is Legionella and what species it would be; there is only preliminary data from metagenomics performed on samples from 3 patients.
Etiology
Legionellosis is caused by bacteria of the Legionellaceae family, which consists of more than 42 species.
Clinical picture
Patients with legionellosis typically have fever, chills, and a cough, which may be dry or with mucus. Some patients also have muscle pain, headache, fatigue, loss of appetite, and occasionally diarrhea. Laboratory tests indicate that these patients' kidneys are not working properly. Chest x-ray frequently shows pneumonia. It is difficult to distinguish Legionnaires' disease from other types of pneumonia simply by symptoms; Other tests are needed to establish your diagnosis.
Recent studies show in rat macrophages, cell death through the activation of cytosolic receptors Naip5 (Birc1e).[6]
People with Pontiac fever suffer from fever and muscle aches and do not have pneumonia. They take 2 to 5 days to recover without treatment.
The time between the patient's exposure to the bacteria and the onset of Legionnaires' disease is 2 to 5 days; for Pontiac fever, the period is shorter, generally from hours to 2 days. The onset or recovery is variable.
Diagnosis
Despite its easy growth in water systems, it is quite difficult to grow in vitro. As a consequence, most diagnoses are based on serological techniques to detect increased antibodies. Diagnosing legionellosis requires a special test that is not routinely performed on people who have fever or pneumonia. Therefore, the doctor should consider the possibility of legionellosis with a view to obtaining appropriate testing. Sputum, pleural fluid, bronchial washings, and lung biopsies or aspirates can be examined by immunofluorescence and with a modification for Dieterle spirochetes.
There are various types of tests. The most useful ones detect the bacteria in mucus, find legionella antigens in urine, or compare the levels of antibodies to legionella in two blood samples obtained 3 to 6 weeks apart.
Treatment
Erythromycin and levofloxacin are the antibiotics currently recommended to treat people suffering from Legionnaires' disease. In the most severe cases, rifampicin can be used as a second medication. Other medicinal substances are available for patients who do not tolerate erythromycin. Pontiac disease does not require specific treatment.
Prevention
Contenido
Los fundamentos de la prevención de la legionelosis son el diseño y mantenimiento mejorados de las torres de refrigeración y los sistemas de conducción de agua —especialmente del agua caliente sanitaria—, para limitar el crecimiento y expansión de los microorganismos de la legionela.
Durante las epidemias, los investigadores de los departamentos de sanidad tratan de identificar la fuente de la enfermedad, hacen recomendaciones adecuadas de prevención y toman medidas de control, como la descontaminación de la fuente de agua. Las investigaciones actuales ofrecerán en el futuro otras estrategias de prevención adicionales.
La legionela es muy vulnerable a dosis altas de cloro. El soporte férrico influye en su crecimiento, por lo que se consigue mediante el hierro de las tuberías de agua y es muy peligrosa en las alcachofas de las duchas, por eso es mejor que sean de plástico.
Action levels
The European Working Group on Legionella Infections (EWGLI)[7] was established in 1986 within the framework of the European Union to share knowledge and experience on the possible sources of Legionella and its control. This group has published guidelines[8] regarding actions that should be taken to limit the number of colony-forming units (i.e., the "aerobic count") of microorganisms per mL at 30 °C (minimum 48 h incubation):
Almost all natural water sources contain Legionella and its presence should not be taken as an indication of a problem. The figures presented are the total aerobic count, rca/mL at 30 °C (minimum 48 h of incubation) with colony count determined by the pour-plate method according to ISO 6222(21) or in a Petri dish and yeast extract agar. Isolation of Legionella can be performed using the method developed by the United States Center for Disease Control using yeast charcoal buffered agar extract with antibiotics.
Many other government agencies, cooling tower manufacturers, and industrial trade organizations have developed design and maintenance guidelines to prevent or control the growth of Legionella in cooling towers. However, in the United States there are no regulations requiring testing or maintaining any specified levels in these facilities.
People of any age can develop legionellosis, but the disease more frequently affects men over 45 years of age, smokers and immunocompromised (either due to diseases such as cancer, diabetes or AIDS; dialysed or taking medicines that suppress the immune system.[1].
Legionnaires' disease outbreaks occur when people have inhaled aerosols containing water (for example, from air conditioning cooling water towers, fountains, irrigation sprinklers, showers) contaminated with Legionella bacteria. People can be exposed to these aerosols at home, workplaces, hospitals, and public places. Legionnaires' disease is not transmitted from person to person and there is no evidence of infection of the disease in car air conditioners or home air conditioning units.
The largest outbreak of legionellosis in history took place in July 2001 in Murcia, Spain, with 6 deaths and more than 600 affected. The focus was located in several ventilation towers: in El Corte Inglés, in the Ministries of Health and Agriculture, in the San Esteban Palace and at the Caja Murcia headquarters.[4].
Another outbreak took place during the autumn of 2014 in Catalonia, Spain, with 10 deaths (six in Sabadell and four in Ripollet) and more than forty people infected, four of them hospitalized and one very serious. The focus of this outbreak has not been clarified.[5].
Another outbreak emerged in May 2018 in the city of Úbeda, Jaén, Andalusia with 4 people admitted to the ICU, currently unresolved.
The newest outbreak to date is in the Province of Tucumán, Argentina, with 5 deaths. The focus was on Luz Medica, a private clinic. Until September 4, 2022, there is a lack of confirmatory evidence that it really is Legionella and what species it would be; there is only preliminary data from metagenomics performed on samples from 3 patients.
Etiology
Legionellosis is caused by bacteria of the Legionellaceae family, which consists of more than 42 species.
Clinical picture
Patients with legionellosis typically have fever, chills, and a cough, which may be dry or with mucus. Some patients also have muscle pain, headache, fatigue, loss of appetite, and occasionally diarrhea. Laboratory tests indicate that these patients' kidneys are not working properly. Chest x-ray frequently shows pneumonia. It is difficult to distinguish Legionnaires' disease from other types of pneumonia simply by symptoms; Other tests are needed to establish your diagnosis.
Recent studies show in rat macrophages, cell death through the activation of cytosolic receptors Naip5 (Birc1e).[6]
People with Pontiac fever suffer from fever and muscle aches and do not have pneumonia. They take 2 to 5 days to recover without treatment.
The time between the patient's exposure to the bacteria and the onset of Legionnaires' disease is 2 to 5 days; for Pontiac fever, the period is shorter, generally from hours to 2 days. The onset or recovery is variable.
Diagnosis
Despite its easy growth in water systems, it is quite difficult to grow in vitro. As a consequence, most diagnoses are based on serological techniques to detect increased antibodies. Diagnosing legionellosis requires a special test that is not routinely performed on people who have fever or pneumonia. Therefore, the doctor should consider the possibility of legionellosis with a view to obtaining appropriate testing. Sputum, pleural fluid, bronchial washings, and lung biopsies or aspirates can be examined by immunofluorescence and with a modification for Dieterle spirochetes.
There are various types of tests. The most useful ones detect the bacteria in mucus, find legionella antigens in urine, or compare the levels of antibodies to legionella in two blood samples obtained 3 to 6 weeks apart.
Treatment
Erythromycin and levofloxacin are the antibiotics currently recommended to treat people suffering from Legionnaires' disease. In the most severe cases, rifampicin can be used as a second medication. Other medicinal substances are available for patients who do not tolerate erythromycin. Pontiac disease does not require specific treatment.
Prevention
Contenido
Los fundamentos de la prevención de la legionelosis son el diseño y mantenimiento mejorados de las torres de refrigeración y los sistemas de conducción de agua —especialmente del agua caliente sanitaria—, para limitar el crecimiento y expansión de los microorganismos de la legionela.
Durante las epidemias, los investigadores de los departamentos de sanidad tratan de identificar la fuente de la enfermedad, hacen recomendaciones adecuadas de prevención y toman medidas de control, como la descontaminación de la fuente de agua. Las investigaciones actuales ofrecerán en el futuro otras estrategias de prevención adicionales.
La legionela es muy vulnerable a dosis altas de cloro. El soporte férrico influye en su crecimiento, por lo que se consigue mediante el hierro de las tuberías de agua y es muy peligrosa en las alcachofas de las duchas, por eso es mejor que sean de plástico.
Action levels
The European Working Group on Legionella Infections (EWGLI)[7] was established in 1986 within the framework of the European Union to share knowledge and experience on the possible sources of Legionella and its control. This group has published guidelines[8] regarding actions that should be taken to limit the number of colony-forming units (i.e., the "aerobic count") of microorganisms per mL at 30 °C (minimum 48 h incubation):
Almost all natural water sources contain Legionella and its presence should not be taken as an indication of a problem. The figures presented are the total aerobic count, rca/mL at 30 °C (minimum 48 h of incubation) with colony count determined by the pour-plate method according to ISO 6222(21) or in a Petri dish and yeast extract agar. Isolation of Legionella can be performed using the method developed by the United States Center for Disease Control using yeast charcoal buffered agar extract with antibiotics.
Many other government agencies, cooling tower manufacturers, and industrial trade organizations have developed design and maintenance guidelines to prevent or control the growth of Legionella in cooling towers. However, in the United States there are no regulations requiring testing or maintaining any specified levels in these facilities.