Isolation and Characterization of Shewanella alga from Human Clinical Specimens and Emendation of the Description of S. alga Simidu et al., 1990, 335

Abstract

Genetic and phenotypic studies on the strains biochemically identified as Shewanella putrefaciens, which had a G+C content ranging from 52 to 54 mol% were conducted. The moles percent G+C of the type strain of S. putrefaciens is 46. Surprisingly, DNA homology experiments revealed that all these strains are genetically related to Shewanella d g a (which was reported to produce tetrodotoxin), not to the type strain of S. putrefaciens. In this study, we reidentified clinical strains of S. putrefaciens which have a high range of moles percent G+C, as does S. alga. We also characterized the reidentified strains and found that the original description of S. alga (U. Simidu, K. Kita-Tsukamoto, T. Yasumoto, and M. Yotsu, Int. J. Syst. Bacteriol. 4k331-336, 1990) is insufficient to identify this strain. An emended description of S. alga is given.The organism now called Shewanella putrefaciens was first described in 1931 and classified as a member of the genus Achromobacter (4). In 1941, it was transferred to the genus Pseudomonas (16) on the basis of morphology. In 1972, it was transferred to the genus Alteromonas (1) on the basis of G+C content. Finally, in 1985, it was transferred to a new genus, Shewanella, on the basis of comparative 5s rRNA sequences (17). The type species of Shewanella is S. putrefaciens (17).Many of the strains classified as S. putrefaciens were isolated from diverse sources, including environmental sources, such as spoilage flora of foods (12, 14, 18,28), oil fields (24), and the ocean (1, 13), and diverse clinical sources, such as patients with otitis, bronchitis, pneumonia, and urinary tract infections (3, 6, 9, 14, 15, 21, 22,29). However, the collected strains were heterogeneous and there were differences between environmental and clinical isolates (9,14,20,21,23,24,28). Owen et al. (20) divided the 10 environmental strains and 16 clinical strains into four groups. Group IV consisted of nine clinical strains. The moles percent G+C value for group IV (52.6) was clearly higher than those for the other three groups (43.9 to 46.9). All four groups retained the species identification of S. putrefaciens, despite the obvious heterogeneity and moles percent G+C values ranging from 43 to 55 (2).Recently, we noticed that most strains isolated from human clinical specimens and identified as S. putrefaciens showed beta-hemolysis on sheep blood agar. However, environmental strains were nonhemolytic. These hemolytic strains had 52 to 54 mol% G+C. Although the hemolytic strains are biochemically identified as S. putrefaciens according to the description in the Manual of Clinical Microbiology (7), they exhibited high levels of DNA homology with the type strain of S. alga. In this study, we present evidence that these clinical strains of S. putrefaciens should be identified as S. alga and emend the description of S. alga * Corresponding author. S. alga is known to be a tetrodotoxin (lTX)-producing bacterium (25,26). Production of TTX by some newly reidentified strains was examined. This is the first report o...

Shewanella gelidimarina sp. nov. and Shewanella frigidimarina sp. nov., Novel Antarctic Species with the Ability To Produce Eicosapentaenoic Acid (20:5 3) and Grow Anaerobically by Dissimilatory Fe(III) Reduction

“…S. putrefaciens ACAM 574 and ACAM 575T (DNA hybridization group I), ACAM 576 (group II), and ACAM 577 (group 111) were closely related to each other, exhibiting levels of dissimilarity of only 0.5 to 2.4%. DNA hybridization group IV of S. putrefaciens has been recognized previously as being equivalent to S. alga (32). The 16s rRNA sequence of S. alga ACAM 541T is closely related to the S. alga FeRed sequence (37), exhibiting a level of dissimilarity of 1.5%, and S. alga clearly represents a distinct lineage within the genus Shewanella (Fig.…”

Polyunsaturated fatty acids in marine bacteria — a dogma rewritten

“…However, more recent reports attributed EPA production to s. putrefaciens strains (Matsui et al, 1991;Nichols et al, 1994;Jarstensen & Landfald, 1997). During this period S. putrefaciens Groups I1 and IV were renamed as Shewanella baltica and Shewanella alga, respectively (Ziemke et al, 1998;Simidu et al, 1990;Nozue et al, 1992). A further three new species (Shewanella benthica, S. hanedai and Shewanella colwelliana) had also been described yet their fatty acid compositions had not been determined (MacDonell & Colwell, 1985 ;Weiner et al, 1988 ;Coyne et a/., 1989).…”

Shewanella loihica sp. nov., isolated from iron-rich microbial mats in the Pacific Ocean

“…While many Shewanella strains remain uncharacterized, there are 32 recognized Shewanella species: the latter were isolated from a variety of sources, primarily aquatic environments and sediments (Bowman et al, 1997;Bozal et al, 2002;Brettar et al, 2002;Coyne et al, 1989;Ivanova et al, 2001Ivanova et al, , 2003aIvanova et al, , b, 2004aLeonardo et al, 1999;Makemson et al, 1997;Nogi et al, 1998;Nozue et al, 1992;Satomi et al, 2003Satomi et al, , 2006Skerratt et al, 2002;Toffin et al, 2004;Venkateswaran et al, 1998Venkateswaran et al, , 1999Xu et al, 2005;Yoon et al, 2004a, b;Zhao et al, 2005Zhao et al, , 2006Ziemke et al, 1998). The bacteria of this genus have attracted great attention because of their diverse respiratory capacities, illustrated by their ability to utilize a wide range of terminal electron acceptors, including oxygen, nitrate, metals and sulfur compounds (Kostka et al, 1996;Myers & Nealson, 1988;Venkateswaran et al, 1999; http://www.…”