What is the morphology of Legionella pneumophila?
Curved, straight or bean-shaped: bacilli come in many variants and are widely spread. Legionella pneumophila is a rod-shaped, Gram-negative, aerobic bacterium in the Legionellaceae family.
What is the most distinguishable feature of Legionella pneumophila infection?
The primary feature of the pathogenesis of Legionella is their ability to multiply intracellularly. But the whole infection process in both protozoa and mammalian cells including bacterial cell attachment to host cells, survival, intracellular replication, and cell-to-cell spread all indicate its pathogenesis [18].
What is a characteristic of the bacterium Legionella pneumophila?
CHARACTERISTICS: Legionella pneumophila is a gram negative, strictly aerobic bacterium of the Legionellaceae family(3). It exhibits poor staining and can appear in different forms. In lung or sputum samples, L. pneumophila appears as a small to short rod with a length of 3 to 5 μm.
Is Legionella pneumophila Gram positive or negative?
The Legionella bacterium is a small, aerobic, waterborne, gram-negative, unencapsulated bacillus that is nonmotile and oxidase and catalase positive. Legionella bacterium is a fastidious organism and will not grow anaerobically on a standard media.
What are the pathogenic mechanisms of Legionella pneumophila?
Pathogenesis. Legionella bacilli reside in surface and drinking water and are usually transmitted to humans in aerosols. The bacteria multiply intracellularly in alveolar macrophages. Recruited neutrophils and monocytes, as well as bacterial enzymes, produce destructive alveolar inflammation.
What is Legionella in microbiology?
Legionella bacteria are aerobic, gram-negative, intracellular pathogens that are important causes of community-acquired and nosocomial pneumonia. Legionella infections can be acquired sporadically or during outbreaks. Legionella bacteria are typically transmitted via inhalation aerosols from contaminated water or soil.
Why does legionella belong to the microorganisms that are difficult to diagnose?
Failure to diagnose Legionnaires’ disease is largely due to a lack of clinical awareness. In addition, legionellae, the bacteria that cause this disease, are fastidious and not easily detected. Legionellae are gram-negative bacteria found in freshwater environments.
What type of pathogen is Legionella pneumophila?
A member of the genus Legionella, L. pneumophila is a Gram negative aerobic, flagellated, non-spore forming bacteria. It is pathogenic, known to be the cause of Legionnaires’ Disease, a severe, often deadly form of pneumonia.
Does Legionella pneumophila Gram stain?
Legionella stains poorly with Gram stain, stains positive with silver, and is cultured on charcoal yeast extract with iron and cysteine.
What color is Legionella?
Legionella micro-colonies should appear green colour and Legionella pneumophila micro-colonies appear red. Twenty-one environmental water samples analysed by standard culture plus five control samples (Two sterile water samples with Legionella as positive controls and three sterile water samples as negative controls).
