4 results on '"Solveig Langsrud"'
Search Results
2. Whole-Genome Sequencing Analysis of Listeria monocytogenes from Rural, Urban, and Farm Environments in Norway: Genetic Diversity, Persistence, and Relation to Clinical and Food Isolates
- Author
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Annette Fagerlund, Lene Idland, Even Heir, Trond Møretrø, Marina Aspholm, Toril Lindbäck, and Solveig Langsrud
- Subjects
Farms ,Whole Genome Sequencing ,Ecology ,Food Microbiology ,Animals ,Genetic Variation ,Listeriosis ,Listeria monocytogenes ,Applied Microbiology and Biotechnology ,Ecosystem ,Food Science ,Biotechnology - Abstract
Listeria monocytogenes is a ubiquitous environmental bacterium associated with a wide variety of natural and human-made environments, such as soil, vegetation, livestock, food processing environments, and urban areas. It is also among the deadliest foodborne pathogens, and knowledge about its presence and diversity in potential sources is crucial to effectively track and control it in the food chain. Isolation of L. monocytogenes from various rural and urban environments showed higher prevalence in agricultural and urban developments than in forest or mountain areas, and that detection was positively associated with rainfall. Whole-genome sequencing (WGS) was performed for the collected isolates and for L. monocytogenes from Norwegian dairy farms and slugs (218 isolates in total). The data were compared to available data sets from clinical and food-associated sources in Norway collected within the last decade. Multiple examples of clusters of isolates with 0 to 8 whole-genome multilocus sequence typing (wgMLST) allelic differences were collected over time in the same location, demonstrating persistence of L. monocytogenes in natural, urban, and farm environments. Furthermore, several clusters with 6 to 20 wgMLST allelic differences containing isolates collected across different locations, times, and habitats were identified, including nine clusters harboring clinical isolates. The most ubiquitous clones found in soil and other natural and animal ecosystems (CC91, CC11, and CC37) were distinct from clones predominating among both clinical (CC7, CC121, and CC1) and food (CC9, CC121, CC7, and CC8) isolates. The analyses indicated that ST91 was more prevalent in Norway than other countries and revealed a high proportion of the hypovirulent ST121 among Norwegian clinical cases.
- Published
- 2022
3. Surveillance of Listeria monocytogenes: Early Detection, Population Dynamics, and Quasimetagenomic Sequencing during Selective Enrichment
- Author
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Birgitte Moen, Eva M. Wagner, Merete Rusås Jensen, Solveig Langsrud, Annette Fagerlund, and Trond Møretrø
- Subjects
Nanopore ,L. monocytogenes ,Listeria ,MDA ,Population Dynamics ,Population ,quasimetagenomics ,Early detection ,Computational biology ,medicine.disease_cause ,shotgun sequencing ,Applied Microbiology and Biotechnology ,background microbiota ,Illumina ,Listeria monocytogenes ,qualitative detection ,RNA, Ribosomal, 16S ,medicine ,selective enrichment ,Quasimetagenomics ,education ,education.field_of_study ,IMS ,ISO 11290-1 ,Ecology ,biology ,Shotgun sequencing ,Microbiota ,Multiple displacement amplification ,multiple displacement amplification ,immunomagnetic separation ,biology.organism_classification ,16S ribosomal RNA ,qPCR ,Genes, Bacterial ,Food Microbiology ,Metagenomics ,Nanopore sequencing ,Food Science ,Biotechnology - Abstract
In this study, we addressed different aspects regarding the implementation of quasimetagenomic sequencing as a hybrid surveillance method in combination with enrichment for early detection of Listeria monocytogenes in the food industry. Different experimental enrichment cultures were used, comprising seven L. monocytogenes strains of different sequence types (STs), with and without a background microbiota community. To assess whether the proportions of the different STs changed over time during enrichment, the growth and population dynamics were assessed using dapE colony sequencing and dapE and 16S rRNA amplicon sequencing. There was a tendency of some STs to have a higher relative abundance during the late stage of enrichment when L. monocytogenes was enriched without background microbiota. When coenriched with background microbiota, the population dynamics of the different STs was more consistent over time. To evaluate the earliest possible time point during enrichment that allows the detection of L. monocytogenes and at the same time the generation of genetic information that enables an estimation regarding the strain diversity in a sample, quasimetagenomic sequencing was performed early during enrichment in the presence of the background microbiota using Oxford Nanopore Technologies Flongle and Illumina MiSeq sequencing. The application of multiple displacement amplification (MDA) enabled detection of L. monocytogenes (and the background microbiota) after only 4 h of enrichment using both applied sequencing approaches. The MiSeq sequencing data additionally enabled the prediction of cooccurring L. monocytogenes strains in the samples. IMPORTANCE We showed that a combination of a short primary enrichment combined with MDA and Nanopore sequencing can accelerate the traditional process of cultivation and identification of L. monocytogenes. The use of Illumina MiSeq sequencing additionally allowed us to predict the presence of cooccurring L. monocytogenes strains. Our results suggest quasimetagenomic sequencing is a valuable and promising hybrid surveillance tool for the food industry that enables faster identification of L. monocytogenes during early enrichment. Routine application of this approach could lead to more efficient and proactive actions in the food industry that prevent contamination and subsequent product recalls and food destruction, economic and reputational losses, and human listeriosis cases.
- Published
- 2021
4. Biofilm Formation and the Presence of the Intercellular Adhesion Locus ica among Staphylococci from Food and Food Processing Environments
- Author
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Knut Rudi, Solveig Langsrud, Askild Lorentz Holck, Lene Hermansen, Maan Singh Sidhu, and Trond Møretrø
- Subjects
Meat ,Food Handling ,Staphylococcus ,Virulence ,Locus (genetics) ,Biology ,Sodium Chloride ,medicine.disease_cause ,N-Acetylglucosaminyltransferases ,Applied Microbiology and Biotechnology ,DNA, Ribosomal ,Poultry ,Microbiology ,RNA, Ribosomal, 16S ,medicine ,Animals ,Northern blot ,Gene ,Phylogeny ,Southern blot ,DNA Primers ,Ecology ,Base Sequence ,Biofilm ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Blotting, Southern ,Glucose ,Genes, Bacterial ,Biofilms ,Food Microbiology ,Polystyrenes ,Bacteria ,Food Science ,Biotechnology - Abstract
In clinical staphylococci, the presence of the ica genes and biofilm formation are considered important for virulence. Biofilm formation may also be of importance for survival and virulence in food-related staphylococci. In the present work, staphylococci from the food industry were found to differ greatly in their abilities to form biofilms on polystyrene. A total of 7 and 21 of 144 food-related strains were found to be strong and weak biofilm formers, respectively. Glucose and sodium chloride stimulated biofilm formation. The biofilm-forming strains belonged to nine different coagulase-negative species of Staphylococcus. The icaA gene of the intercellular adhesion locus was detected by Southern blotting and hybridization in 38 of 67 food-related strains tested. The presence of icaA was positively correlated with strong biofilm formation. The icaA gene was partly sequenced for 22 food-related strains from nine different species of Staphylococcus , and their icaA genes were found to have DNA similarities to previously sequenced icaA genes of 69 to 100%. Northern blot analysis indicated that the expression of the ica genes was higher in strong biofilm formers than that seen with strains not forming biofilms. Biofilm formation on polystyrene was positively correlated with biofilm formation on stainless steel and with resistance to quaternary ammonium compounds, a group of disinfectants.
- Published
- 2003
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