Legionella oakridgensis: unusual new species isolated from cooling tower water

Abstract

We describe a new species of Legionella represented by 10 strains isolated from industrial cooling towers. Legionella oakridgensis differed genetically from the other seven species of Legionella in DNA hybridization studies and differed serologically in direct fluorescent-antibody tests. The new species, unlike all other species except L. jordanis, did not require added L-cysteine for growth in serial transfer on charcoal-yeast extract agar. L. oakridgensis, as well as three other species tested, required L-cysteine for primary isolation from animal tissues. L. oakridgensis was the only species of Legionella that failed to produce alkaline phosphatase at pH 8.5. In all other respects, it resembled other species of Legionella, including having a high content of branched-chain cellular fatty acids and being pathogenic for guinea pigs. These bacteria have not yet been associated with human disease, but they are potential causes of legionellosis. Colonization of air conditioning equipment by legionellae is recognized in the United States and abroad as a potential major public health problem because strong circumstantial evidence indicates that cooling towers and evaporative condensers have frequently been the source of legionellae involved in outbreaks of both mild and severe respiratory disease (2, 11, 12, 16). The maintainence of equipment free of these organisms is a desirable objective but one that has not yet been achieved by practical means. In this study we describe 10 strains isolated from thermally altered water of large industrial cooling towers in two different geographic locations (R. Tyndall, S. B. Gough, C. B. Fliermans, E. Dominque, and C. Duncan, submitted for publication). These cultures were characterized by morphological, cultural, biochemical, genetic, serological, and pathogenicity tests. They represent a new species, for which the name Legionella oakridgensis sp. nov. is proposed. The type strain of L. oakridgensis is Oak Ridge 10 (OR-10; ATCC 33761). MATERIALS AND METHODS Cultures. Tyndall and co-workers in Oak Ridge, Tenn., isolated the strains of L. oakridgensis designatt Publication 2103, Environmental Sciences Division, Oak Ridge National Laboratory.

Legionella sainthelensi: a new species of Legionella isolated from water near Mt. St. Helens

“…Like other legionellae, L. sainthelensi contains relatively large amounts (50 to 62%) of the total acids as branched-chain acids (4,6,(16)(17)(18). Quantitatively, the fatty acid composition of L. sainthelensi is most similar to those of L. bozemanii (4,14,18), L. Iongbeachae (16), L.…”

“…The fatty acids of these six isolates are qualitatively similar to those of other Legionella species with the characteristic features of the presence of isobranched-chain 14-and 16-carbon acids (i-14:0, i-16:0) and anteisobranched-chain 15-and 17-carbon acids (a-15:0, a-17:0) together with relatively large amounts of a monounsaturated straight-chain 16-carbon acid (16:1) and the absence of individual hydroxy acids at concentrations greater than 1% (6,(16)(17)(18). Like other legionellae, L. sainthelensi contains relatively large amounts (50 to 62%) of the total acids as branched-chain acids (4,6,(16)(17)(18). Quantitatively, the fatty acid composition of L. sainthelensi is most similar to those of L. bozemanii (4,14,18), L. Iongbeachae (16), L.…”

Vaccination against Legionella pneumophila: serum antibody correlates with protection induced by heat-killed or acetone-killed cells against intraperitoneal but not aerosol infection in guinea pigs

“…This organism is apparently found worldwide, as evidenced by documented outbreaks in Europe, Israel, Scandinavia, and Australia (6). Since 1976, eight additional serogroups of L. pneumophila and seven additional species have been recognized (2,26). Legionella bacteria have been responsible for numerous focal outbreaks of pneumonia as well as isolated cases, with many of the latter appearing in immunocompromised hosts (5).…”

The life stage‐specific pathometabolism of Legionella pneumophila

“…Various experimental studies and the analysis of various genome sequences revealed that L. pneumophila is auxotrophic for Arg, Cys, Ile, Leu, Met, Thr and Val, and the amino acids Arg, Cys, Ile, Leu, Met, (Phe), Ser, Thr, (Tyr) and Val are essential for growth . Cysteine is absolutely required for the growth of legionellae, and media must be supplemented with cysteine to support growth of L. pneumophila , but this is not true for L. oakridgensis , a less virulent Legionella species . Generally, genes for serine‐O‐acetyltransferase and cysteine synthase are not present in the genome sequences of legionellae, with the exception of L. oakridgensis .…”