Numerical Taxonomy of Psychrotrophic Pseudomonads

Abstract

The taxonomy of 218 psychrotrophic pseudomonad strains (200 field strains from meat and 18 type and reference strains) was numerically studied by 174 biochemical and physiological tests. All strains were Gram-negative rods, oxidative positive and motile by means of one or more polar flagella. The strains clustered into 15 groups, of which 9 were regarded as major clusters. The major clusters were designated as Pseudomonas fragi (112 strains), P. fluorescens biotype III (7 strains), P. fluorescens biotype I (16 strains). P. aureofaciens/chlororaphis (3 strains), P. fluorescens biotype II (3 strains), P. putida biotype I (4 strains), Alteromonas putrefaciens (10 strains) and Aeromonas hydrophila biotype I (5 strains). One major cluster, containing 21 strains (cluster 2), was left unassigned. The phenotypic data indicate that this cluster might represent a new species. The P. fluorescens/P. putida complex matched closely the descriptions of Stanier et al. (1966), but the two largest clusters (1 and 2) were not in agreement with any species described in the eighth edition of Bergey's Manual of Determinative Bacteriology. Cluster 1 included the type strain (ATCC 4973) of the hitherto incompletely described P. fragi. A simplified scheme for the separation between P. fragi, P. fluorescens, P. putida and cluster 2 is presented.

Effect of Chilling on Microbiological, Biochemical and Sensory Attributes of Whole Aquacultured Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792)

“…Pseudomonas were counted on Cetrimide-FusidinCephaloridine (CFC) agar (Oxoid code CM 559, supplemented with SR 103; Oxoid U.K.) after 3 days incubation at 20°C. [17,18]. Aeromonas spp.…”

“…A 5-8 black colonies each were isolated and characterized from IA, VRBGA and SA agar plates at the final sampling points. They were then grouped according to the taxonomic schemes proposed by several authors for identification (Dainty et al [25]; Molin and Ternstorm [17]; Krieg and Holt [26]; Sneath et al [27]; Kirov [28]; Brenner et al [29]). The isolated cultures were identified and confirmed using API 20NE and API 20NE system (Biomerieux, France).…”

DNA Relatedness among Pseudomonas Strains Isolated from Natural Mineral Waters and Proposal of Pseudomonas veronii sp. nov.

“…The saprophytic species of fluorescent pseudomonads are characterized by the production of water-soluble pigments (pyoverdins) and can be distinguished from the phytopathogenic species by their positive arginine dihydrolase reaction, their more rapid growth in most media, and their ability to utilize certain substrates. The complexity of the fluorescent saprophytes other than P. aeruginosa (considered a homogeneous species [32]) has been well illustrated by extensive studies (2,7, 23,29,30,35,47). In total, 81 biovars were recognized by Jessen (23).…”

“…Table 1) and identified as fluorescent pseudomonads) according to the criteria of Palleroni (32), and 67 (type and collection) strains included for control purposes (see Table 2). They represent 13 Pseudomonas species (P. aeruginosa, P. fluorescens biovars I to V, P. marginalis, P. chlororaphis, P. aureofaciens, P. putida biovars A and €3, P. syringae, P. ViridifEava, P. cichorii, P. stutzeri, P. mendocina, P. alcaligenes, and P. pseudoalcaligenes) belonging to section I of the genus Pseudomonas as described by Palleroni (32); the psychrotrophic species of importance to food microbiology, P. fragi and P. lundensis (29,30); the fluorescent organisms isolated from plants and mushrooms of Palleroni's section V (34), P. agarici, P. asplenii, P. caricapupayae, and P. tolaasii; and P. savastanoi, a recently described species among the pathovar strains of P. syringae (18).…”

Use of a Marker Organism To Model the Spread of Central Nervous System Tissue in Cattle and the Abattoir Environment during Commercial Stunning and Carcass Dressing

“…The identity of presumptive isolates of the marker organism was confirmed by biochemical tests (20).…”