Publications by authors named "Rolf Sommer Kaas"

Most investigations of geographical within-species differences are limited to focusing on a single species. Here, we investigate global differences for multiple bacterial species using a dataset of 757 metagenomics sewage samples from 101 countries worldwide. The within-species variations were determined by performing genome reconstructions, and the analyses were expanded by gene focused approaches.

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  • Salmonella enterica serovar Dublin (S. Dublin) is primarily a cattle pathogen in Denmark, but it can occasionally infect humans.
  • A study analyzed 421 genomes of S. Dublin to assess the impact of a national surveillance program on its population size over time, finding a significant decrease from 2014 to 2019.
  • The results showed that enhanced surveillance likely contributed to the reduction in both S. Dublin’s population in cattle and human infection cases, demonstrating the importance of genomic sequencing and phylogenetic analysis in public health measures.
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Antimicrobial resistance (AMR) is one of the most important health threats globally. The ability to accurately identify resistant bacterial isolates and the individual antimicrobial resistance genes (ARGs) is essential for understanding the evolution and emergence of AMR and to provide appropriate treatment. The rapid developments in next-generation sequencing technologies have made this technology available to researchers and microbiologists at routine laboratories around the world.

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Storage of biological specimens is crucial in the life and medical sciences. Storage conditions for samples can be different for a number of reasons, and it is unclear what effect this can have on the inferred microbiome composition in metagenomics analyses. Here, we assess the effect of common storage temperatures (deep freezer, -80°C; freezer, -20°C; refrigerator, 5°C; room temperature, 22°C) and storage times (immediate sample processing, 0 h; next day, 16 h; over weekend, 64 h; longer term, 4, 8, and 12 months) as well as repeated sample freezing and thawing (2 to 4 freeze-thaw cycles).

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One Health surveillance of antimicrobial resistance (AMR) depends on a harmonized method for detection of AMR. Metagenomics-based surveillance offers the possibility to compare resistomes within and between different target populations. Its potential to be embedded into policy in the future calls for a timely and integrated knowledge dissemination strategy.

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C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with in biofilms. The draft genome of C6 is 3.7 Mbp and was shaped by mobile genetic elements.

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subsp. bacteria are highly diverse foodborne pathogens that are subdivided into more than 1,500 serovars. The diversity is believed to result from mutational evolution, as well as intra- and interspecies recombination that potentially could be influenced by restriction-modification (RM) systems.

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We describe 2 fatal cases of methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 septicemia in persons who had no contact with livestock. Whole-genome sequencing of the isolated MRSA strains strongly suggest that both were of animal origin and that the patients had been infected through 2 independent person-to-person transmission chains.

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  • One case of extended-spectrum-beta-lactamase (ESBL)-producing Salmonella enterica serovar Typhi was identified and analyzed through whole-genome sequencing.
  • The strain showed similarities to an existing strain with the blaSHV-12 gene from the Philippines.
  • This finding suggests that the strain may be part of an undiscovered outbreak, marking the first instance of ESBL-producing S. Typhi.
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The Firmicutes represent a major component of the intestinal microflora. The intestinal Firmicutes are a large, diverse group of organisms, many of which are poorly characterized due to their anaerobic growth requirements. Although most Firmicutes are Gram positive, members of the class Negativicutes, including the genus Veillonella, stain Gram negative.

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Objectives: Antimicrobial susceptibility testing of bacterial isolates is essential for clinical diagnosis, to detect emerging problems and to guide empirical treatment. Current phenotypic procedures are sometimes associated with mistakes and may require further genetic testing. Whole-genome sequencing (WGS) may soon be within reach even for routine surveillance and clinical diagnostics.

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A draft genome sequence of the yeast Pachysolen tannophilus CBS 4044/NRRL Y-2460 is presented. The organism has the potential to be developed as a cell factory for biorefineries due to its ability to utilize waste feedstocks. The sequenced genome size was 12,238,196 bp, consisting of 34 scaffolds.

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