Legionella pneumophila :: Essays Papers

Legionella pneumophila GRAPHIntroductionLegionella pneumophila argon gram-negative rods. They are very(prenominal) difficult to culture because of their complex nutrient requirements, such as cysteine, high concentrations of iron, and the use of activated charcoal agar. They survive as intracellular pathogens of either phylum Protozoa or human macrophages. They are most often found in stagnant water reservoirs like air conditioning cooling towers, whirlpool spas, humidifiers, faucets and shower stall heads, and are infectious when inhaled. L. pneumophila was first identified and named later the American Legion convention of 1976, held in Philadelphia, PA. 182 people became infected, and 29 died (most of which were older men or seat smokers). Although this organism was named in the 70s, retrospective studies showed cases since 1943. GRAPHDiseasesL. pneumophila has a very wide range of effects. Healthy indi viduals usually go through an asymptomatic seroconversion, age less healthy people may undergo Pontiac Fever or Legionnaires Disease (LD). In 1968, employees at the county health department in Pontiac, Michigan came overcome with a fever, but the responsible pathogen was not identified at the time. It was frozen and later diagnosed as L. pneumophila. Pontiac Fever, being milder than LD, generally does not need treatment. Infected individuals lead show fever, muscle aches, and headaches, and usually recover between 2-5 days. Pontiac Fever will present symptoms anywhere from a couple of hours to a couple of days after exposure, while LD takes 2-10 days to incubate. LD patients have fever, chills and a cough, with x-rays showing pneumonia. This more severe form usually prevails in elderly, cigarette smokers, people with chronic lung disease, or those who are immunocompromised, such as cancer or AIDS patients.VirulenceBeing a gram-negative bacterium, L. pneumophila has lipopolysaccha rides (LPS) that act as endotoxin within a human host. The straw man of a flagella is thought to mediate adherence to human lung cells, thereby causing infection, since flagella-less strains do not cause disease. Once attached to human cells, the organism is engulfed by a macrophage where is utilizes the internal environment to multiply.