One species, Legionella micdadei, and the amoeba host, has been discovered in highly acidic geothermal environments. However, optimal growth occurs between 25 and 40 degrees Celsius. They can grow at a range of temperatures, anywhere from 5 to 63 degrees Celsius. In addition, the bacteria can be found in cooling towers, air conditioners, spa equipment, fountains, humidifiers, or showers. Legionella occur in high amounts in thermally polluted water. Legionella are aquatic organisms, inhabiting freshwater environments humans are accidental hosts. Some antibiotics that can be used include azithromycin, which attacks the 50S subunit of the bacterial ribosome to inhibit translation of mRNA into proteins, and ciprofloxacin, which inhibits DNA gyrase and topioisomerase IV in order to stop the separation of DNA antiparallel strands, thereby inhibiting cell division. This characteristic, in addition to the fact that they are gram-negative and can form biofilms, makes Legionnaires' Disease difficult to treat in humans. A particularly unique characteristic of Legionella is that they can survive in alveolar macrophages. In addition, the hosts make Legionella more resistant to adverse environmental conditions. The amoebas provide the bacteria with an ideal environment for reproduction and development. This plays a major role in their virulence. Legionella are often found to be intracellular pathogens of free-living protozoa and other aquatic eukaryotes. It is self-contained, usually running its course in two to five days. The symptoms of this disease include fever and muscle aches. This illness was names after the place of discovery: Pontiac, Michigan. Other Legionella species are associated with a disease called Pontiac fever, a systemic illness. Because Legionella form symbiotic relationshiops with amoebas, outbreaks of the disease are often correlated with the presence of amoebas. Air-conditioning cooling towers, whirlpool spas, sink taps and shower heads are all major sources for L. Legionnaire's disease is most commonly spread through aerosols. Alcohol abuse may be a factor, but that has not yet been determined. In addition, males are more likely to become infected with L. Risk factors for Legionnaire's disease include: immunosuppression, cigarette smoking, renal failure, age greater than 50 years, AIDS, hematologic malignancies, and lung cancer. Immunocompromised individuals are less likely to survive an infection than immunocompetent patients. If left untreated, the disease has a 5-80% mortality rate. The four major methods for diagnosis are: determination of antibody level, demonstration of the bacterium in tissues or body fluids by using immunofluorescent microscopy, actual isolation of the organism on culture media, and detection of antigenuria. Legionnaire's disease is difficult to distinguish from any other type of pneumonia. It was first discovered in Philadelphis in 1976, when it caused an outbreak of pneumonia at an American Legion Convention, infecting 221 people and killing 34. Legionella pneumophila is the bacteria that causes Legionnaire's disease. Evidence suggests that a majority, if not all, legionella are associated with biofilms. In these types of environments, extracellular growth is often a necessity, and the biofilms permit this growth. Legionella have the capability of surviving within biofilms, particularly in man-made water systems.
They have developed flagella and are highly toxic. In the second phase, called the infectious phase, the bacteria are shorter and thicker. During this period, the bacteria are nonmotile and have a low toxicity. The first is called the replicative phase. There are two major phases to the life cycle. In addition, many Legionella species, such as Legionella lytica, are parasites of eukaryotic cells, and aquire energy from their hosts.
Most species are motile, and have one to three polar or lateral flagellae.
Virulence Factors of Pathogenic Bacteria. Lens was also complete in October of 2004, in addition to the complete genome. Plasmid pLPL of Legionella pneumophila str.
#LEGIONELLA SKETCHY MICRO FULL#
Plasmid pLPP of Legionella pneumophila str.Paris was completed in October of 2004 the full genome was completed around the same time. Research on the Legionella genome structure is underway. Legionella has a bad reputation because of its pathogenicity, although complete recovery from Legionnaire's is probable upon proper diagnosis. Although largely aquatic, they can thrive in areas other than lakes and streams (see below). Legionella is best known for causing Legionnaire's disease. Legionella is related to the genus Coxiella. Bacteria Proteobacteria Gammaproteobacteria Legionellales Legionellaceae
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