Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Helsel LO[original query] |
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Characterization of Burkholderia rhizoxinica and B. endofungorum isolated from clinical specimens.
Gee JE , Glass MB , Lackner G , Helsel LO , Daneshvar M , Hollis DG , Jordan J , Morey R , Steigerwalt A , Hertweck C . PLoS One 2011 6 (1) e15731 Eight isolates submitted to CDC from 1989 to 2006 from clinical specimens were initially identified as members of the genus Burkholderia based on preliminary cellular fatty acid analysis and/or 16S rRNA gene sequencing. With the recent descriptions of the new species B. rhizoxinica and B. endofungorum, which are considered endosymbiotic bacteria in Rhizopus microsporus fungi, we now identify seven of these clinical isolates as B. rhizoxinica and one as B. endofungorum based on biochemical testing, 16s rRNA, and DNA-DNA hybridization results. We also further characterize these isolates by assessing toxin production and/or by multiple locus sequence typing. |
Identification and characterization of clinical Bacillus spp. isolates phenotypically similar to Bacillus anthracis
Beesley CA , Vanner CL , Helsel LO , Gee JE , Hoffmaster AR . FEMS Microbiol Lett 2010 313 (1) 47-53 Bacillus anthracis, the etiological agent of anthrax, is a gram-positive, spore-forming rod, with colonies exhibiting a unique ground-glass appearance, and lacking hemolysis and motility. In addition to these phenotypes, several others traits are characteristic of B. anthracis such as susceptibility to gamma phage, the presence of two virulence plasmids (pX01 and pX02), and specific cell wall and capsular antigens that are commonly detected by direct fluorescent-antibody assays. We report on the identification and characterization of 14 Bacillus megaterium and four Bacillus sp. clinical isolates that are nonhemolytic, nonmotile, and produce a capsule antigenically similar to B. anthracis. This work furthers our understanding of Bacillus diversity and the limitations of the assays and phenotypes that are used to differentiate species in this genus. Further work is necessary to understand whether these strains are opportunistic pathogens or just contaminates. |
Listeria marthii sp. nov., isolated from the natural environment, Finger Lakes National Forest
Graves LM , Helsel LO , Steigerwalt AG , Morey RE , Daneshvar MI , Roof SE , Orsi RH , Fortes ED , Millilo SR , den Bakker HC , Wiedmann M , Swaminathan B , Sauders BD . Int J Syst Evol Microbiol 2009 69 (6) 1280-1288 Four isolates (FSL S4-120T, FSL S4-696, FSL S4-710, and FSL S4-965) of Gram-positive, motile, facultatively anaerobic, non-sporeforming bacilli that were phenotypically similar to Listeria spp. were isolated from soil, standing water, and flowing water samples obtained from the natural environment in the Finger Lakes National Forest, New York, USA. The four isolates were closely related to one another and were determined to be the same species by whole genome DNA-DNA hybridization studies (>82% relatedness at 55 degrees C and >76% relatedness at 70 degrees C with 0.0-0.5% divergence). 16S ribosomal RNA sequence analysis confirmed their close phylogenetic relatedness to L. monocytogenes and L. innocua and more distant relatedness to L. welshimeri, L. seeligeri, L. ivanovii, and L. grayi. Phylogenetic analysis of partial sequences for sigB, gap, and prs showed that these isolates form a well-supported sistergroup to L. monocytogenes. The four isolates were sufficiently different from L. monocytogenes and L. innocua by DNA-DNA hybridization to warrant their designation as a new Listeria species. The four isolates yielded positive reactions in the AccuProbe(R) test that is purported to be specific for L. monocytogenes, did not ferment L-rhamnose, were non-hemolytic on blood agar media, and did not contain a homologue of the L. monocytogenes virulence gene island. On the basis of their phenotypic characteristics and their genotypic distinctiveness from L. monocytogenes and L. innocua, the four isolates should be classified as a new species within the genus Listeria, for which the name Listeria marthii sp. nov. is proposed. The type strain of L. marthii is FSL S4-120T (=ATCC BAA 1595T =BEIR NR 9579T =CCUG 56148T). L. marthii has not been associated with human or animal disease at this time. |
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