Legionella pneumophila

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Legionella pneumophila
Scientific classification
Kingdom: Bacteria Phylum: Proteobacteria Class: Gamma Proteobacteria Order: Legionellales Family: Legionellacease Genus: Legionella Species: L. pneumophila
Binomial name
Legionella pneumophila

Description and significance

Legionella pneumophila is a rod shaped, flagellated and a gram negative bacteria. L. pneumophila are aerobic and non-capsulated. It is known to be pathogenic to humans and leads to legionellosis or legionnaires’ disease. This species is determined to be the dominant human pathogen in its genus of 41 different species . It was first found to be pathogenic in 1976 when a group of men were found to be infected. It spread to more than 200 individuals and led to 34 casualties. It was first isolated by inoculation of a guinea pig with the blood sample of an infected person in 1947.

Genome structure

There are three genomes from the species L. pneumophila that have been studied well. These are Legionella pneumophila str. Paris, Legionella pneumophila str. Lens and Legionella pneumophila ssp. Pneumophila str. Philadelphia 1. All three of these genomes have been completed recently between 2001 and 2004.

Name	Genes	Base Pairs	Year
Legionella pneumophila str. Paris	3136	3,503,610	2004
Legionella pneumophila str. Lens	3001	3,345,687	2004
Legionella pneumophila ssp. Pneumophila str. Philadelphia 1	3002	3,397,754	2001

Ecology

In general L. pneumophila can be found in aquatic environments worldwide.

Pathology

There are 41 different species in the genus Legionella and these are further divided into 64 serogroups. The serogroups 1, 4, and 6 are responsible for most human infections of legionnaires’ disease. Serogroup 1 is determined to be the cause of 70-90% of such infections.

Year	Male	Female	Total
1999	42	14	56
2000	125	29	154
2001	78	8	86
2002	139	29	167
2003	127	20	147
2004	151	9	160
2005	252	29	281
2006	452	66	518
2007	527	141	668
2008	529	157	686