Enzymatic activities of Legionella pneumophila and Legionella-like organisms

Abstract

The API ZYM system was used to investigate enzymatic activities of Legionella pneumophila and other Legionella-like organisms. Leucine aminopeptidase, alkaline and acid phosphatase, butyrate and caprylate esterase, and phosphoamidase activities were consistently detected in all strains tested. No evidence of myristate lipase, trypsin, chymotrypsin, or glycosidase activity was found. Legionella pneumophila and Legionella-like organisms have emerged as significant respiratory pathogens in certain patient populations. There exist relatively few biochemical tests based on positive reactions for identification of this group of organisms (9, 11). Biochemical characterization is complicated by the fact that these organisms have an unusual metabolism characterized by the ability to use amino acids as the major source of energy and carbon (8). They also do not grow on standard laboratory media. Definitive identification of an isolate as one of the described species requires gas-liquid chromatography of cellular fatty acids (14) or direct immunofluorescent staining (3). We examined the enzymatic profiles of nonproliferating cells by using the 19 chromogenic substrates comprising the API ZYM system (Analytab Products, Plainview, N.Y.). While this study was in progress, Muller (16) published the enzymatic profiles of four strains of L. pneumophila, using the API ZYM system. We expand upon his observation with L. pneumophila and extend it to other described species, considered by some to be in the genus Legionella (1, 2, 10, 12, 13) and by others to be in the genera Tatlockia and Fluoribacter (7). Nine strains of L. pneumophila, designated Bellingham 1 (serogroup 1), California 1 (serogroup 1), Knoxville 1 (serogroup 1), Philadelphia 2 (serogroup 1), Togus 1 (serogroup 2), Bloomington 2 (serogroup 3), Los Angeles 1 (serogroup 4), Dallas I-E (serogroup 5), and Chicago 2 (serogroup 6), and one strain each of L. micdadei (Tatlock), L. gormanii (LS-13), L. bozemanii (WIGA), L. dumoffii (TEX-KL), and L. longbeachae (Longbeach 4), were studied. L.

Development of the BIOLOG substrate utilization system for identification of Legionella spp

“…All of the L. pneumophila strains consistently metabolized Tween 40, Tween 80, methylpyruvate, ,3-hydroxybutyrate, a.-ketobutyrate, ox-ketovalerate, alaninamide, L-alanine, L-glutamate, glycyl-L-glutamate, L-leucine, L-proline, L-serine, L-threonine, and urocanate ( Table 1). The ability to utilize Tween 40 and Tween 80 suggests that L. pneumophila possesses esterase activity similar to that reported by Muller (18) and Nolte et al (19), except that our data suggest that the strains we investigated are able to split esters of higher fatty acids, as indicated by the metabolism of Tween 40 and Tween 80. Interestingly, although urocanate is an intermediate in histidine metabolism, only one of the strains tested, the serogroup 5 strain (NCTC 11405), was able to metabolize histidine within the 24-h incubation period.…”

“…Our results seem to support this, as we found no metabolism of a-ketoglutarate, although the other keto-acids in the panel were metabolized by almost all of the strains investigated. All the strains tested metabolized methylpyruvate and ,-hydroxybutyrate, and most metabolized Tween 40 and Tween 80, suggesting that they possesses esterase activity, as reported previously (18,19). However, this may not be due to specific esterase activity but may be due to protease activity (24).…”

Biochemical fingerprints of Legionella spp. by the BIOLOG system: presumptive identification of clinical and environmental isolates

“…has been accomplished by techniques such as fluorescent antibody, DNA probes, latex fixation and biochemical tests all requiring highly complex equipment and trained personnel (Steele et al 1990). The BIOLOG system and the APY ZYM system are based on biochemical profiles (Nolte et al 1982). However, theoretical comparison of the APY ZYM system and the BIOLOG system reveals that the latter has the advantage of having considerably more substrates and not being pH-dependent.…”

“…These tests can take more than one week. The enzymatic APY ZYM system (Nolte et al 1982) is too limited and non-specific for laboratory identification. We studied the BIOLOG system which uses metabolic fingerprints as a possible time-saving tentative test to improve Legionella spp.…”

Enzymatic profiles of 11 barophilic bacteria under in situ conditions: evidence for pressure modulation of phenotype

“…Humble et al (6) reported the system useful for enzymatic characterization of bacteria, yielding enzyme profiles for both gram-positive and gram-negative bacteria. Since 1977, API ZYME enzyme test kits have been used successfully to characterize a wide range of microorganisms of clinical importance (1,8,10,11).…”