Bacteria Genomes- Legionella Pneumophila - Report Example

General Instructions 1. To enter your information, click on the grey shaded box and just start typing. The box will expand as you fill in the information. 2. For help with filling in the information, refer to the technical specifications handout. 3. Fill in the information as fully as possible, using complete sentences. Background Information Name of your microorganism: Legionella pneumophila Type of microorganism: Legionella pneumophila is a rod-shaped, motile, gram-negative, aerobic bacterium and is a facultative parasite of fresh water protozoa. Family: Legionellaceae      First described/identified by: Legionella pneumophila was first identified by investigators from the Center for Disease Control and Prevention in the year 1976. An outbreak of pneumonia which affected about 220 attendees at an American Legion Conference and resulting in 34 deaths, led to an investigation by the CDC researchers. They determined that the reason for the outbreak was saturation of the hotel’s air conditioning system by an unknown strain of bacteria and termed it as L. pneumophila along with related Legionella species. Name of the associated disease(s): Legionnaire’s Disease Inoculation & Identification Describe the culture conditions: Legionella pneumophila is a fastidious organism and requires a high concentration of cysteine and low amount of sodium and other essential growth promoting factors for its growth in culture medium. They also thrive well in conditions that contain high amounts of rust, algae and organic particles as these are good sources of iron and nitrogen for the organism. About 48 hours of incubation is required before the organism is visible in the culture medium. Characterise the microorganism: Legionella pneumophila is a motile, rod-shaped, aerobic, gram-negative bacterium. It is a non-marine bacterium that is generally found growing inside aquatic protozoa’s such as amoeba. Within the human body the organism can grow inside alveolar macrophages. Apart from the aquatic environment they can also be found in soils, fresh water and biofilms where again they grow within protozoan organisms. They grow to their optimum in temperatures ranging from 20 to 45 0C. It has also been found that they can survive under tap water for a period of up to a year. Significance Discuss the significance/importance of your organism in its’ most common environment: Legionella pneumophila in their natural environment grow with other organisms, mostly protozoa’s such as Hartmanella vermiformis. The organism more or less establishes an endosymbiotic relationship with the host protozoan. These organisms multiply within the host and a large amount of Legionella bacteria are present within a single amoeba, which is sufficient to infect a human being. List some statistical information for this microorganism: The first outbreak of the Legionnaire’s disease, later found to be caused by Legionella pneumophila, was in the year 1976 when about 220 World War veterans attending the American Legion Convention were infected by the organism resulting in 34 deaths. In 1999, there were 133 people affected by the disease during a flower show at Netherlands in which 11 percent of the cases reportedly died. Another outbreak of the disease occurred in 2000, when 119 people were affected by the disease which resulted in four deaths. EWGLI data shows that since 1993 the number of people affected by the disease has been on a steady rise and CDC estimates have shown that about 10,000 to 20,000 people are affected by the disease every year, but the number reported to health authorities is relatively low. Disease Information Symptoms: The major clinical feature of the disease is pneumonia. However the initial signs of the disease include anorexia, fatigue, myalgia and headache. The more specific symptoms of the disease are chronic cough, high fever with chills, abdominal pain, vomiting and diarrhea. People generally become delirious and as the disease progresses heavy damage to the lungs occur as the organism can multiply within the lung alveoli, once inside the body, causing respiratory failure. Other complications include renal failure, hypotension and shock. Incubation Period: While it may take about 2 to 10 days post-infection to notice the initial signs of the disease, the incubation period for the onset of clinical symptoms is about 5 to 6 days. Pathogenesis: An individual is infected by the bacterium once they inhale it and the bacteria enter the alveolar macrophage overcoming the immune defense put forward by the host. The bacteria are ingested by the process of phagocytosis by which the bacteria enters the macrophages in the form of a phagosome and it begins to replicate within this protected vacuole. However it loses some of its virulent characteristics and hence fuses with a lysosome to form a replicative and virulent phagolysosome. Eventually lyses of the macrophage and subsequent infection of nearby cells begins leading to disease progression. Epidemiology: Several reports of outbreaks of Legionnaire’s disease have been reported and the two recent reports were in the years 1999 and 2000 due to contamination of a whirlpool spa and air conditioning system by the bacterium respectively. Additionally nosocomial outbreaks, especially in hospitals, have also been reported due to exposure of susceptible individuals to aerosols containing the organism. Infection can occur through open wounds. However it must be stressed that individuals who have a compromised immune system are likely to be more susceptible to the illness. In addition, elderly people, those with lung infection and smokers are also at risk. Treatment: Treatment with drugs is the treatment of choice for the disease. Antibiotics belonging to the class of macrolids are being used for the treatment. These include azithromycin, erythromycin and clarithromycin. In sever cases other drugs such as ciprofloxacin, rifampicin and tetracycline are also used. Problems with treatment: Antibiotics may result in an upset stomach or may cause rashes and other such allergic reactions. In case of Rifampicin use, urine and other body secretions turn orange in color. Prevention: Analyzing the major sources of contamination, stagnant water appears to be a major source where the organism survives, especially at 25 to 50 0 temperatures. Thus water systems such as cooling towers and condensers need to be suitably designed and maintained so as to minimize contamination with such microbes. Maintaining a high temperature within the hot- water systems would help to kill such organisms as they cannot survive at such high temperatures. In other places suitable disinfection procedures need to be used. Surveillance of all the measures employed should be done and strict measures need to be implemented while examining samples from infected patients in hospitals. Control: Continuous monitoring of all the safety precautions taken to prevent transmission of the illness is required. While total prevention of sporadic infections is not quite possible, nevertheless suitable prevention strategies need to be employed in places where the chances of infection are greater. Find a recent (i.e., within the last 3 years) news article related to your microorganism. Discuss the information from the article in your own words: Source of article: New Insights to Legionella pneumophila. The Medical News. (2008). Retrieved November 17, 2009, from, http://www.news-medical.net/news/2008/02/07/35034.aspx News: The report provides information that research work has suggested that the L.pneumophila belonging to the Sg1 serogroup has been detected in most clinical cases. It is believed that its higher virulence is a main reason for its infection despite the fact that this serogroup accounts for only 30% of the organism in the environment. Genome analysis using DNA arrays have been carried out to compare Sg1 and other isolates of Legionella and other known potentially virulent genes. The study has revealed that the Sg1 serogroup caries a cluster of Lipopolysaccahride (LPS) synthesis genes which is considered to be a major reason behind it high prevalence in humans as LPS is a normal component of the cell wall. Another significant identification is that of a clone of Sg1 which is being considered to cause sporadic and worldwide outbreaks. This identification would help to find out other genetic factors that may aid in the interaction of the organism with the host and would also help in developing newer methods of detection. References & Resources 1. Legionella Pneumophila – General Information. (n.d). Retrieved November 17, 2009, from http://www.corisbio.com/public/product/documents/GeneralInformationLegionella-v1_000.pdf 2. Swanson, M.S., & Hammer, B.K. (2000). Legionella pneumophila pathogenesis: A Fateful Journey from Amoeba to Macrophages. Annual Review of Microbiology, 54, 567-613 3. EMBL- EBI. Bacteria Genomes- Legionella Pneumophila. (n.d). Retrieved November 17, 2009, from, http://www.ebi.ac.uk/2can/genomes/bacteria/Legionella_pneumophila.html 4. Legionella Bacteria. (n.d). Retrieved November 17, 2009, from, http://s99.middlebury.edu/BI330A/projects/Cocchiaro/page2.htm 5.      Fischer, T. (2001). Legionella Pneumophila Pneumonia- Legionnaire’s Disease. Retrieved November 17, 2009, from, http://www.healthon.com/topics/L/2/Legionella-Pneumophila-Pneumonia/Legionnaires-Disease/info/Overview-Causes-&-Risk-Factors.html 6.       Columbia Genome Center. (n.d). Legionella pneumophila subsp. Pneumophila str. Philadelphia 1. Retrieved November 17, 2009, from, http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=13147 Website address for picture/image: Electron micrograph of Legionella pneumophila attached to the end of Hartmanella vermiformis, one of the many amoebae this bacteria has been associated with. [Image] (n.d). Retrieved November 17, 2009, from, http://s99.middlebury.edu/BI330A/projects/Cocchiaro/page2.htm Pre-submission Checklist:      Submitted by             Read More