Table of Contents
What are the virulence factors of Legionella pneumophila?
VIRULENCE FACTORS OF LEGIONELLA PNEUMOPHILA. L. pneumophila possesses many of the traditional bacterial determinants that are important for pathogenicity in other bacteria, including lipopolysaccharide (LPS), flagella, pili, a type II secretion system (T2SS), and outer membrane proteins.
Is Legionella pneumophila a virulent pathogen?
However, the presence of the Legionella in the water systems has not always caused outbreaks. One of the main reasons of this is the virulence of the bacteria that are inhaled. For this reason, Legionella pathogenicity must be considered along with their presence in water system.
What are three potential sources of exposure to the bacteria that causes Legionnaires disease?
Causes and Common Sources of Infection
- Showerheads and sink faucets.
- Cooling towers (structures that contain water and a fan as part of centralized air cooling systems for buildings or industrial processes)
- Hot tubs.
- Decorative fountains and water features.
- Hot water tanks and heaters.
- Large, complex plumbing systems.
What are the characteristics of 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.
How is Legionella pneumophila transmitted?
The most common route of transmission is by inhalation of aerosolized water containing the bacteria, although transmission can sometimes occur through aspiration of water containing the bacteria. A single episode of possible person-to-person transmission of Legionnaires’ disease has been reported.
What is the reservoir for Legionella pneumophila?
RESERVOIR: L. pneumophila is found naturally in most fresh water sources, including lakes, ponds, and rivers(1,12,13). It is found in cooling towers, plumbing systems, water heaters, and warm water spas(3,7). It has also been isolated from soil samples(14).
Is Legionella pneumophila aerobic?
Legionella pneumophila is a thin, aerobic, pleomorphic, flagellated, non-spore-forming, Gram-negative bacterium of the genus Legionella. L. pneumophila is the primary human pathogenic bacterium in this group and is the causative agent of Legionnaires’ disease, also known as legionellosis.
What is the main cause of Legionella?
The most common form of transmission of Legionella is inhalation of contaminated aerosols. Sources of aerosols that have been linked with transmission of Legionella include air conditioning cooling towers, hot and cold water systems, humidifiers and whirlpool spas.
What promotes the growth of Legionella bacteria?
When there is a reduction in disinfectant levels in your building water systems, Legionella can grow. In some buildings, processes such as heating, storing, and filtering can reduce the amount of available disinfectant, allowing Legionella to grow if steps are not taken to stop it.