Lin Thorstensen Brandal

Publications of Lin Thorstensen Brandal

• First report of shiga-toxin 1 in Sorbitol-fermenting Escherichia coli O157:H-

  Authors: Lin Thorstensen Brandal, Inger Løbersli, Trine-Lise Stavnes, Astrid Louise Wester, Bjørn-Arne Lindstedt

  Journal of clinical microbiology. 02/2012;

  Sorbitol-fermenting Escherichia coli O157:H- (SF O157) is an emerging pathogen and several outbreaks have been detected in Europe the last few years (12).…

• Identification of the anti-terminator q(O111:H) (-) gene in Norwegian sorbitol-fermenting Escherichia coli O157:NM.

  Authors: Kjersti Haugum, Bjørn-Arne Lindstedt, Inger Løbersli, Georg Kapperud, Lin Thorstensen Brandal

  FEMS microbiology letters. 01/2012;

  Sorbitol-fermenting Escherichia coli O157:NM (SF O157) is an emerging pathogen suggested to be more virulent than nonsorbitol-fermenting Escherichia coli O157:H7 (NSF O157). Important virulenceSorbitol-fermenting Escherichia coli O157:NM (SF O157) is an emerging pathogen suggested to be more virulent than nonsorbitol-fermenting Escherichia coli O157:H7 (NSF O157). Important virulence factors are the Shiga toxins (stx), encoded by stx1 and/or stx2 located within prophages integrated in the bacterial genome. The stx genes are expressed from p(R) (') as a late protein, and anti-terminator activity from the Q protein is necessary for read through of the late terminator t(R) (') and activation of p(R) (') . We investigated the regulation of stx2(EDL933) expression at the genomic level in 17 Norwegian SF O157. Sequencing of three selected SF O157 strains revealed that the anti-terminator q gene and genes upstream of stx2(EDL933) were identical or similar to the ones observed in the E. coli O111:H- strain AP010960, but different from the ones observed in the NSF O157 strain EDL933 (AE005174). This suggested divergent stx2(EDL933) -encoding bacteriophages between NSF O157 and the SF O157 strains (FR874039-41). Furthermore, different DNA structures were detected in the SF O157 strains, suggesting diversity among bacteriophages also within the SF O157 group. Further investigations are needed to elucidate whether the q(O111:H) (-) gene observed in all our SF O157 contributes to the increased virulence seen in SF O157 compared to NSF O157. An assay for detecting q(O111:H) (-) was developed.

• Comparison of multilocus variable-number tandem-repeat analysis and multilocus sequence typing for differentiation of hemolytic-uremic syndrome-associated Escherichia coli (HUSEC) collection strains.

  Authors: Christian Jenke, Björn Arne Lindstedt, Dag Harmsen, Helge Karch, Lin Thorstensen Brandal, Alexander Mellmann

  Journal of clinical microbiology. 08/2011; 49(10):3644-6.

  Multilocus variable-number tandem-repeat analysis (MLVA) was compared to multilocus sequence typing (MLST) to differentiate hemolytic uremic syndrome-associated enterohemorrhagic Escherichia coliMultilocus variable-number tandem-repeat analysis (MLVA) was compared to multilocus sequence typing (MLST) to differentiate hemolytic uremic syndrome-associated enterohemorrhagic Escherichia coli strains. Although MLVA--like MLST--was highly discriminatory (index of diversity, 0.988 versus 0.984), a low level of concordance demonstrated the limited ability of MLVA to reflect long-term evolutionary events.

• Study of polymorphic variable-number of tandem repeats loci in the ECOR collection and in a set of pathogenic Escherichia coli and Shigella isolates for use in a genotyping assay.

  Authors: Bjørn-Arne Lindstedt, Lin Thorstensen Brandal, Lena Aas, Traute Vardund, Georg Kapperud

  Journal of microbiological methods. 05/2007; 69(1):197-205.

  The Escherichia coli (E. coli) reference collection, ECOR, consists of 72 strains that are representative of the genotypic diversity, as indexed by multilocus enzyme electrophoresis (MLEE), in theThe Escherichia coli (E. coli) reference collection, ECOR, consists of 72 strains that are representative of the genotypic diversity, as indexed by multilocus enzyme electrophoresis (MLEE), in the species as a whole. MLEE revealed 4 main phylogenetic groups designated A, B1, B2 and D. We present a study of the relationship between the ECOR strains as determined by polymorphisms in seven variable-number of tandem repeats (VNTR) loci. Seven tandem repeats that were present in more than one of the fully sequenced E. coli strains were selected, and primers were constructed in order to amplify the targets in all species where the loci were present. The combined result for all VNTR loci was adapted as a multiple-locus variable-number tandem repeats analysis (MLVA) and showed that the ECOR collection was divided into 63 distinct genotypes. The ECOR phylogenetic groups defined by MLEE were not well conserved by MLVA. A set of 61 pathogenic isolates of both E. coli and Shigella spp. was then tested with the same set of VNTR loci, and revealed 54 distinct genotypes. In addition, the MLVA method was used to genotype isolates from patients and suspected sources in a recent outbreak of E. coli O103 in Norway. The pathogenic E. coli isolates contained the diarrhea causing categories EIEC, EAEC, STEC, ETEC and EPEC. Shigella isolates were of species S. flexneri, S. boydii, S. sonnei and S. dysenteriae. The MLVA method rapidly genotyped all isolates in the study at a Simpson's index of diversity of D=0.98.

• Octaplex PCR and fluorescence-based capillary electrophoresis for identification of human diarrheagenic Escherichia coli and Shigella spp.

  Authors: Lin Thorstensen Brandal, Bjørn-Arne Lindstedt, Lena Aas, Trine-Lise Stavnes, Jørgen Lassen, Georg Kapperud

  Journal of microbiological methods. 03/2007; 68(2):331-41.

  A multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic EscherichiaA multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic Escherichia coli and Shigella spp. The virulence genes selected for each category were Stx1, Stx2, and eaeA for enterohemorrhagic E. coli (EHEC), eaeA for enteropathogenic E. coli (EPEC), STIb and LTI for enterotoxigenic E. coli (ETEC), ipaH for enteroinvasive E. coli (EIEC) and Shigella spp., and aggR for enteroaggregative E. coli (EAEC). Each forward primer was labelled with a fluorochrome and the PCR products were separated by multicolour capillary electrophoresis on an ABI PRISM310 Genetic Analyzer (Applied Biosystems). If present, several gene variants of each virulence gene were identified. The internal control gene rrs, encoding 16S rRNA, was amplified in all 110 clinical strains analyzed. Virulence genes were demonstrated in 103 (94%) of these strains. In the majority of the cases (98/103, 95%), classification obtained by the novel multiplex PCR assay was in agreement with that previously determined by phenotypic assays combined with other molecular genetic approaches. Numerous multiplex PCR assays have been published, but only a few of them detect all five E. coli pathotypes within a single reaction, and none of them has used multicolour capillary electrophoresis to separate the PCR products. The octaplex PCR assay followed by capillary electrophoresis presented in the present paper provides a simple, reliable, and rapid procedure that in a single reaction identifies the five main pathotypes of E. coli, and Shigella spp. This assay will replace the previous molecular genetic methods used in our laboratory and work as an important supplement to the more time-consuming phenotypic assays.

• Octaplex PCR and fluorescence-based capillary electrophoresis for identification of human diarrheagenic Escherichia coli and Shigella spp.

  Authors: Lin Thorstensen Brandal, Bjørn-Arne Lindstedt, Lena Aas, Trine-Lise Stavnes, Jørgen Lassen, Georg Kapperud

  Journal of Microbiological Methods.

  A multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic EscherichiaA multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic Escherichia coli and Shigella spp. The virulence genes selected for each category were Stx1, Stx2, and eaeA for enterohemorrhagic E. coli (EHEC), eaeA for enteropathogenic E. coli (EPEC), STIb and LTI for enterotoxigenic E. coli (ETEC), ipaH for enteroinvasive E. coli (EIEC) and Shigella spp., and aggR for enteroaggregative E. coli (EAEC). Each forward primer was labelled with a fluorochrome and the PCR products were separated by multicolour capillary electrophoresis on an ABI PRISM™310 Genetic Analyzer (Applied Biosystems). If present, several gene variants of each virulence gene were identified. The internal control gene rrs, encoding 16S rRNA, was amplified in all 110 clinical strains analyzed. Virulence genes were demonstrated in 103 (94%) of these strains. In the majority of the cases (98/103, 95%), classification obtained by the novel multiplex PCR assay was in agreement with that previously determined by phenotypic assays combined with other molecular genetic approaches. Numerous multiplex PCR assays have been published, but only a few of them detect all five E. coli pathotypes within a single reaction, and none of them has used multicolour capillary electrophoresis to separate the PCR products. The octaplex PCR assay followed by capillary electrophoresis presented in the present paper provides a simple, reliable, and rapid procedure that in a single reaction identifies the five main pathotypes of E. coli, and Shigella spp. This assay will replace the previous molecular genetic methods used in our laboratory and work as an important supplement to the more time-consuming phenotypic assays.