Legionellosis as an emergent disease
Legionellosis as an emergent disease
Introduction
Legionella is a recent discovered bacteria which was discovered in 1976. Even though is a recent bacteria, nowadays the treatment for this bacteria exists. So in this article we’ll talk about what is Legionella,what kind of diseases it can cause and it’s history.
What is?
Legionellosis is caused by the bacterium Legionella, which is an aerobic gram-negative bacillus that is spread through aerosolized water particles. It’s severity ranges from a mild flu syndrome to severe pneumonia, sometimes fatal. It affects the respiratory tract. The symptoms are fever, headache, lethargy, muscle aches, diarrhea and, sometimes, bloody cough. The disease can be treated with antibiotics.
There are two types of infection caused by Legionella:
- Pontiac fever: it’s a milder infection with fever and muscle aches that last no longer than a week as the main symptoms.
- Legionnaires’ Disease: more severe infection, that results in pneumonia.
Who have the greatest danger?
Most people exposed to the causative bacteria don’t get sick, and the disease is not transmitted directly from person to person. The majority of patients are over 50 years old. The greatest risk corresponds to people with weakened immune systems or chronic diseases and to smokers and heavy drinkers. The outbreaks are usually related to air conditioning and water distribution systems, humidifiers and jacuzzis with poor maintenance.
Where it produce?
Legionellosis occurs throughout the world, but its frequency is unknown because many countries don’t have a good surveillance systems to detect and diagnose it.
In Australia, Europe and the United States of America, about 10 to 15 cases per million inhabitants are detected.
The bacterium colonizes cooling towers or other facilities that contain water at temperate temperatures, where it tends to multiply. If these bacteria move in aerosols (tiny drops) they can be inhaled, reach the lungs and start the disease. It is not spread from person to person.
Facilities that can transmit legionellosis
High risk facilities:
o Cooling towers and evaporative condensers.
o Industrial humidifying power stations that generate aerosols.
o Sanitary hot water systems with accumulator and return circuit.
o Thermal facilities.
o Jacuzzis, hot tubs and similar facilities.
o Cooling towers and evaporative condensers.
o Industrial humidifying power stations that generate aerosols.
o Sanitary hot water systems with accumulator and return circuit.
o Thermal facilities.
o Jacuzzis, hot tubs and similar facilities.
Low risk facilities:
o Humidifiers.
o Ornamental fountains
o Urban sprinkler irrigation systems.
o Fire water systems.
o Other devices that accumulate water and can produce aerosols.
o Humidifiers.
o Ornamental fountains
o Urban sprinkler irrigation systems.
o Fire water systems.
o Other devices that accumulate water and can produce aerosols.
How it multiplies?
L.pneumophila is an intracelular, facultative bacteria who can colonize and divide inside amoeba sp. to survive and multiply itself. In the case of humans, they colonize macrophage.
The Amobe sp. are used as reservoir and protection of L. Pneumophila from several situations of enviromental stress, such as chlorination. A pseudopodia is wound around the bacteria in the form of phagocytosis. Once internalized, bacteria gets wound inside a vacuole attached to membrane that doesn’t fuse with lysosome, who can degradate bacteria. Bacteria multiply themselves inside this protected compartment. They use an IVB secretion system known as ICM/Dot to inject effector proteins into the host. These effectors increase the bacteria capacity to survive inside a host’s cell, due to the fact that proteins interfere with the vacuole fusion which contains L. Pneumophila with the endosome degradation of the host.
Cultive and detection
To diagnose legionelosis there are different methods of cultivation and detection of the L. Pneumophila which are krown as direct detection methods: Cultivation in BCYE media, detection of the antigen and urine and DNA amplification to detect the L. Pneumophila gene in blood, urine or spit.
On the one hand, the BCYE cultivation is a slow method due to the fact that L. Pneumophila has a long incubation period.
On the other hand, the antigen detection is a faster system but it only identifies a certain number of serogrups, and the antigenuria is not always in all the patients, so this method has a sensibilty of the 65-80%.
That somatic antigen is determined by the side chains of the cell wall. The chain composition and its layout determines the nature of the O antigen, essential in gramnegative bacteria serologic identification.
Thanks to the serology the direct methods are possible to be improved and achieve a sensibility in results aroud the 80%.
Disinfection systems of the different facilities to prevent legionellosis (BOE)
-Maintenance of indoor installations of sanitary hot water and cold water for human consumption:
Domestic hot water: There are two different types of disinfection; disinfection with chlorine and thermal disinfection. Chemical disinfection with chlorine consists of using between 20 and 30 ml of residual chlorine (30o maximum and pH between 7 and 8) and maintaining between 2 and 3 hours. Then neutralize this amount of residual chlorine and empty it, clean the walls and possible incrustations and then fill again. The thermal disinfection consists of emptying the tank, filling it with water and raising it to 70 degrees for 2 hours, opening taps for 5 minutes and, finally, emptying the tank and filling it for normal operation.
Cold water for human consumption: The procedure to be followed for the disinfection of cold water for human consumption will be the same as the chemical disinfection previously mentioned for domestic hot water.
-Maintenance of cooling towers and evaporative condensers:
First, free residual chlorine is added (at least 5 mg / l) and also biodispersants and anticorrosives capable of acting on the biolayer (always maintaining the pH between 7 and 8). Recirculate the system for 3 hours with the fans disconnected and the openings closed to avoid the release of aerosols (during the process the chlorine level will be measured and it will be replaced in case it goes down). Chlorine is neutralized, the tank is emptied and cleaned with water under pressure. Fill with water and add maintenance disinfectant.
Cases of involvment by Legionella
- Hotel Macarena. There was an outbreak in the summer of 2009, causing 15 affected and 4 dead. Seven people were charged: hotel manager, 2 hotel maintenance workers, the hotel chain maintenance manager, the maintenance company technician, the maintenance company director and to the technical manager of the maintenance company.
- Club de Gel de Benalmádena: Outbreak of Legionella with the result of 38 affected and 3 dead. It had to be compensed with 300.000€ to the dead and between 700-2.000 € to those affected as a consequence of seizures and impediments.
- Aigua Club Termal a Tenerife: Thermal water center where there was no maintenance program for the prevention of Legionellosis. Positives were detected in the toning pool, mineral pink, hot tub, pool, gym and Turkish bath. Sentence of 14.342€ to cause the desease.
- Hospital general de Valencia: There a patient entered to perform routine tests and a month later he died. It is shown that the patient contracted the Legionella during this period. It had to be compensed with 12.000€.
- Ondunova, S.A: A worker died who was exposed to contracting the illness in his workplace. It was shown that legionella existed in the water sampling analyzed by the Health Authority. A work- related accident was considered and the insurer had to pay her widow a life pension and compensation, and the children of the deceased received an orphan’s pension.
Conclusions:
Legionellosis is an emergent disease that have became really popular lately. Although it’s not extremelly dangerous it can result to some uncomfortable symptoms. In order to prevent the infection, you should research about Legionella, which the responsalbe bacilum. The research of this bacteria lead us to learn that it colonizes and multiplies facilities that contain water at temperate temperatures such as spa spots.
In conclusion, the research about the bacteria lead us to a solution for a disease that at the beginning resulted really mysterious.
Bibliography
Organizacion Mundial de la Salud. Legionelosis. Recuperat el 22 de Novembre de 2018
Diputació de Barcelona. Información detallada sobre la prevención y el control de la Legionelosis. Recuperat el 24 de Novembre de 2018
Elena G.S (2010). Qué es, dónde está y cómo se contagia la legionela. El Pais. Recuperat el 24 de Novembre de 2018
Vircell Microbiologists. Legionella Pneumophila. Recuperat el 23 de Decembre de 2018
PubMed. Legionnaire’s Disease (Legionella Infection). Recuperat el 3 de Decembre de 2018
Bruce Y, L. (2018). Legionnaire’s Disease: Why is this Potentially Deadly Disease Seemingly On The Rise. Forbes. Recuperat el 3 de Decembre de 2018.
Centros para el control y la prevención de enfermedades( 30 d’Abril de 2018). Legionella(enfermedad del legionario y fiebre de Pontiac). Recuperat el 6 de Decembre de 2018
Ministerio de agricultura, pesca y alimentación; Ministerio de sanidad y consumo; ministerio de economía. (2003) .BOE 171. Recuperat al 8 de Decembre de 2018
M.S.Swanson and B.K.Hammer (2000).Legionella pneumophilia pathogenesis: A Fatefull Journey from amoebae to macrophages. Annual Reviews, 54:567-613. Recuperat el 10 de Decembre del 2018
Micronela.preguntes freqüents. Recuperat el 09 de Decembre de 2018
(Avaluable) In your article, you mention that there are several methods for the detection of Legionella pneumophila, do you know which of them are commonly used for the detection of this microorganism? In recent years, have there been cases of legionellosis in Cataunya?
ResponderEliminarIn Catalunya, 2017, more than 100 cases of Legionella infections with 8 deceased were detected. The most used detection methods are direct methods, cause it has achieved an 80% of sensibility in results.
EliminarEste comentario ha sido eliminado por el autor.
ResponderEliminar(Avaluable)What are the risk factors for Legionella infection?
ResponderEliminarWhat is the cheapest and most effective method to detect legionella? This question is to establish this method in countries with less means for research
There are two types of risk factors for Legionella. Individuals that are smoking, alcoholism, weak immune system ... And environmental such as exposure to aerosols in hotels or infection of sanitary material. To detect Legionella today there is an equipment for industries and smaller that performs the chemical analyzes automatically and if they give positive in a possible proliferation of Legionella sends a warning signal (this does not mean that it is the cheapest, but it is considered the cheaper in how much efficiency).
EliminarEVALUABLE
ResponderEliminarAbout disinfection and detection systems of the Legionellosis, is there an established protocol that public establishments such as municipal swimming pools, public showers, etc. have to comply with? In other words, are they forced to go through certain controls every so often to prevent cases like the ones mentioned?
Thanks,
Ander Congil
Yes, at least once a year or at the end of the season a final report of the evaluation on the effectiveness of the plan, checking the following points:
EliminarDeviations detected in the situation diagnosis ( documentaires, structurals, maintenance and operational) compliance with the actions corrective and their effectiveness.
Deviations detected in the action program (revisions, cleaning, water treatment and analytical controls), compliance with the actions corrective and their effectiveness.
Do these prevention treatments, explained above, guarantee us 100% effectiveness or is there a margin of possibility of survival for these microorganisms?
ResponderEliminarYes, these treatments are 100% effective since the analysis is very specific and can not have any margin of error because it is a bactery that can cause damage for the people.
Eliminar(Avaluable) In your article you mention that the main risk corresponds to people with weakened immune systems. But we know which is the lymphocyte responsable about that? Is lymphocyte T or lymphocyte B or both?
ResponderEliminarThat is important because some people have failure in only one type of lymphocyte (depends on his chronic illness) and that information allows which are the truly people affected.
The lymphocyte responsible about that are known to be both of them, but especially the lymphocyte B, which confers protection from infection.
EliminarEste comentario ha sido eliminado por el autor.
ResponderEliminar(Avaluable)
ResponderEliminarWhat is the characteristic morphology of Legionella? Does it affect to its bacterial properties?
Legionella is a thin, non capsulated, 2-3 microns Gram-negative cocobacilli. It presents a bipolar flagella. Indeed, this morphology affects directly to its bacterial propierties.
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