Primary and secondary structures of rRNA spacer regions in enterococci

Naimi, Afaf; Beck, G; Branlant, Christiane

doi:10.1099/00221287-143-3-823

Cited by 45 publications

(31 citation statements)

References 42 publications

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“…Other methods for identification of enterococci have utilized molecular techniques such as PCR and sequencing (1,6,9,12,22). A previous report identified the manganese-dependent superoxide dismutase gene sodA as an ideal gene for species identification of enterococci (16).…”

Section: Discussionmentioning

confidence: 99%

Use of a Genus- and Species-Specific Multiplex PCR for Identification of Enterococci

2004

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The 16S rRNA gene has previously been used to develop genus-specific PCR primers for identification of enterococci. In addition, the superoxide dismutase gene (sodA) has been identified as a potential target for species differentiation of enterococci. In this study, Enterococcus genus-specific primers developed by Deasy et al. (E1/E2) were incorporated with species-specific primers based upon the superoxide dismutase (sodA) gene for development of a multiplex PCR. This assay provides simultaneous genus and species identification of 23 species of enterococci using seven different reaction mixtures. Accuracy of identification of the multiplex PCR was determined by comparisons to standard biochemical testing, the BBL Crystal kit, VITEK, and API Rapid ID 32 Strep. Isolates from swine feces, poultry carcasses, environmental sources, and retail food were evaluated and, overall, results for 90% of the isolates tested by PCR agreed with results obtained using standard biochemical testing and VITEK. Eighty-five percent and 82% of PCR results agreed with results from the API Rapid ID 32 Strep and BBL Crystal tests, respectively. With the exception of concurrence between identification using standard biochemical testing and VITEK (85%) and between BBL Crystal and VITEK (83%), the percent agreement for PCR was higher than or equal to any other pairwise comparison. Multiplex PCR for genus and species determination of enterococci provides an improved, rapid method for identification of this group of bacteria.

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Section: Discussionmentioning

confidence: 99%

Use of a Genus- and Species-Specific Multiplex PCR for Identification of Enterococci

2004

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“…All of the ITS alleles described in P. damselae contained at least one of six different inverted repeats. Existence of short inverted repeat sequences, which can form putative stem-loop structures within ITS regions has been reported in bacterial taxa (25). It is believed that some of these palindromic structures may be related to the genetic events responsible for the insertion/deletion of DNA sequence blocks.…”

Section: Discussionmentioning

confidence: 99%

Variation in 16S-23S rRNA Intergenic Spacer Regions in Photobacterium damselae : a Mosaic-Like Structure

Osorio

Collins

Romalde

et al. 2005

Appl Environ Microbiol

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Phenotypically, Photobacterium damselae subsp. piscicida and P. damselae subsp. damselae are easily distinguished. However, their 16S rRNA gene sequences are identical, and attempts to discriminate these two subspecies by molecular tools are hampered by their high level of DNA-DNA similarity. The 16S-23S rRNA internal transcribed spacers (ITS) were sequenced in two strains of Photobacterium damselae subsp. piscicida and two strains of P. damselae subsp. damselae to determine the level of molecular diversity in this DNA region. A total of 17 different ITS variants, ranging from 803 to 296 bp were found, some of which were subspecies or strain specific. The largest ITS contained four tRNA genes (tDNAs) coding for tRNA Glu(UUC) , tRNA Lys(UUU)

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“…Today, some aspects of the taxonomic and genotypic diversity within the genus Enterococcus can also be further investigated through the use of recently developed molecular techniques, such as intergenic ribosomal PCR, randomly amplified polymorphic DNA and PFGE (Angeletti et al, 2001;Naïmi et al, 1997;Poyart et al, 2000;Quednau et al, 1998).…”

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Molecular analysis of artisanal Italian cheeses reveals Enterococcus italicus sp. nov.

Fortina

Ricci

Mora

et al. 2004

International Journal of Systematic and Evolutionary Microbiology

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The taxonomic positions of seven atypical Enterococcus strains, isolated from artisanal Italian cheeses, were investigated in a polyphasic study. By using 16S rRNA gene sequencing, DNA-DNA hybridization and intergenic transcribed spacer analysis, as well as by examining the phenotypic properties, the novel isolates were shown to constitute a novel enterococcal species. Their closest relatives are Enterococcus sulfureus and Enterococcus saccharolyticus, having a 16S rRNA gene sequence similarity of 96?7 %. This group of strains can be easily differentiated from the other Enterococcus species by DNA-DNA hybridization and by their phenotypic characteristics: the strains do not grow in 6?5 % NaCl, and they do not produce acid from L-arabinose, melezitose, melibiose, raffinose or ribose. The name Enterococcus italicus sp. nov. is proposed for this species, with strain DSM 15952 T (=LMG 22039 T ) as the type strain.Enterococci constitute a large proportion of the autochthonous bacteria associated with the mammalian gastrointestinal tract and can cause infection from this endogenous source. The incidence of infections caused by enterococci, together with the increasing difficulty of treating such infections because of multiple antibiotic resistance, put these organisms, especially Enterococcus faecium and Enterococcus faecalis, among the emerging human pathogens (Morrison et al., 1997;Robredo et al., 2000). However, enterococci are ubiquitous and can be found as free-living micro-organisms in soil, on plants and in large numbers in dairy products, where, in some cases, they predominate with respect to lactobacilli and lactococci (Franz et al., 1999;Giraffa, 2002). The presence of enterococci in dairy products has long been considered as an indicator of inadequate sanitary conditions during the production and processing of milk. In contrast, many authors suggest that enterococci may have a potentially desirable role in some cheeses, because of their proteolytic and lipolytic activities, in the development of typical flavours and for the production of enterocins with anti-Listeria activity (Ennahar & Deschamps, 2000;Giraffa et al., 1997). The important question is whether enterococci originating from food and from community sources possess an equally pathogenic potential, or whether differences in pathogenicity exists, perhaps in relation to the different species. In this context, correct species identification is of great importance to both medical and food microbiologists.Since the revival of the genus Enterococcus by Schleifer & Kilpper-Bälz (1984), phylogenetic studies have established, on the basis of 16S rRNA gene sequences, the presence of at least four 'species groups' (Devriese et al., 1993;Devriese & Pot, 1995;Stiles & Holzapfel, 1997) For these reasons, a polyphasic approach is desirable for correctly identifying 'unusual' enterococcal strains. Today, some aspects of the taxonomic and genotypic diversity within the genus Enterococcus can also be further investigated through the use of recently developed molec...

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Primary and secondary structures of rRNA spacer regions in enterococci

Cited by 45 publications

References 42 publications

Use of a Genus- and Species-Specific Multiplex PCR for Identification of Enterococci

Use of a Genus- and Species-Specific Multiplex PCR for Identification of Enterococci

Variation in 16S-23S rRNA Intergenic Spacer Regions in Photobacterium damselae : a Mosaic-Like Structure

Molecular analysis of artisanal Italian cheeses reveals Enterococcus italicus sp. nov.

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