Cellular fatty acid compositions and isoprenoid quinone contents of 23 Legionella species

Abstract

The cellular fatty acid compositions and ubiquinone contents of 182 Legionella strains representing 23 species werç determined by çapillary gas-liquid çhromatography and reverse-phase high-perform nce liquid chromatography, respectively. Except for the type strain of Legionella erythra (ATCC 35303T), al! Legionella species contained large (40 to 90%) amounts of branched-chain fatty acids and only trace to small (<0.5 to 5%) amounts of ester-linked hydroxy acids. The 23 species were placed in three major fatty acid groups on the basis of differences in the relative amounts of 14-methylpentadecanoic (C1l6:0), hexadecanoic (C16:), and 12methyltetradecanoic (Ca 5.0) acids. All Legionella species contained ubiquinones with 9 to 14 isoprene units in thç side chains and were divided into five different ubiquinone groups. The species were further differentiated into 16 groups on the basis of qualitative and quantitative differences in their fatty acid compositions and ubiquinone contents. Both of these chemical characteristics can be used to distinguish Legionella species from other gram-negative bacteria and rapidly and accurately identify suspected isolates before serologic and other tests are done.

Interspecies sequence differences in the Mip protein from the genus Legionella: implications for function and evolutionary relatedness

“…data. For explanation of phenotypical and biochemical markers and group definitions, see the following; 1, Wilkinson, (1988);2, Brenner (1987); 3, Lambert and Moss (1989), Wilkinson et al (1990);4, Jantzen et al (1993);5, O'Connell et al (1996). This may be because of the way in which the phenotype is determined (arbitrary classification) or it may be that the character is genuinely homoplastic, i.e. subject to convergence.…”

“…The arbitrariness of some classifications for Legionella can be seen on examination of the criteria on which they are based. L. israelensis has been grouped alternately with ubiquinone group A species (Wilkinson et al, 1990) or with group D species (Lambert and Moss, 1989). The discrepancy is determined solely on a small difference in the amount of ubiquinone 13 (Q13) detected.…”

“…The present study reports the first comparison of 16S RNA-based phylogeny of Legionella with data from another gene, mip. Furthermore, the utility of generally used phenotypical and biochemical characteristics, such as autofluorescence (Wilkinson, 1988), cell wall ubiquinone and fatty acid constituents (Lambert and Moss, 1989;Wilkinson et al, 1990;Jantzen et al, 1993), are compared for their ability to discern evolutionary relationships within the genus.…”

Mistaken identity: Legionella micdadei appearing as acid‐fast bacilli on lung biopsy of a hematopoietic stem cell transplant patient

“…Diagnosis of this bacteria on tissue specimens is further complicated by poor uptake of counterstain by L. micdadei with standard Gram staining, which often makes initial identification of this gram‐negative organism difficult . In this case, there was both a relative paucity of organisms and weak uptake of counterstain, which led to an initial negative reading of the Gram stain.…”

Antigenic and genetic characterization of Leaionella Proteins: Contribution to taxonomy, diagnosis and pathogenesis

“…The Legionellaceae were originally defined as separate from other members of this group by the lack of relatedness in DNA-DNA hybridization experiments to all bacterial species tested. Also, analysis of cellular fatty acids determined characteristic properties unique to the Legionellaceae (Moss et al 1977, Finnerty et al 1979, Lambert & Moss 1989, including an unusually high level of branched-chain fatty acids for a Gram-negative organism. Whereas the establishment of a new family seems to be well justified, the inclusion of all family members into one genus has been a matter of much controversy.…”