1.2 Microbiology and Taxonomy Plate 1.1 bacteria Legionella (www.bbc.co.uk) appear as small rods, faintly staining Gram-negative. They are Legionella unencapsulated and non-spore forming with an average size of 0.5-1.0 µm wide and 1.0-3.0 µm long (Barbaree, 1991). Most species exhibit motility through one or more polar or lateral flagella. cell walls are unique from other Gram-negative Legionella bacteria in that they contain significant amounts of branched-chain cellular fatty acids. require low levels of oxygen for growth (Brenner 1985). Legionella et al., Following the initial identification of after the 1976 outbreak, L. pneumophila numerous species have been discovered within the genus. Currently, the Legionella genus consists of at least 50 species, nine of which can be further divided into serogroups that are genetically homologous but can be differentiated by specific reactivity to antibodies. Currently, 70 serogroups are recognised in the genus, including 16 among (World Health Organisation, 2007). L. pneumophila 3
1.2 Microbiology and Taxonomy Plate 1.1 Legionella bacteria (www.bbc.co.uk) Legionella appear as small rods, faintly staining Gram-negative. They are unencapsulated and non-spore forming with an average size of 0.5-1.0 µm wide and 1.0-3.0 µm long (Barbaree, 1991). Most species exhibit motility through one or more polar or lateral flagella. Legionella cell walls are unique from other Gram-negative bacteria in that they contain significant amounts of branched-chain cellular fatty acids. Legionella require low levels of oxygen for growth (Brenner et al., 1985). Following the initial identification of L. pneumophila after the 1976 outbreak, numerous species have been discovered within the Legionella genus. Currently, the genus consists of at least 50 species, nine of which can be further divided into serogroups that are genetically homologous but can be differentiated by specific reactivity to antibodies. Currently, 70 serogroups are recognised in the genus, including 16 among L. pneumophila (World Health Organisation, 2007). 3
Birgitta-Bedford-Thesis-2012.docx