Browsing by Author "Tegetmeyer HE"

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Population dynamics of Campylobacter jejuni in healthy dairy calves reared with and without exposure to wild birds
(Oxford University Press on behalf of Applied Microbiology International, 2025-12-01) Rapp D; Ross CM; Tegetmeyer HE; Maclean P; French NP; Brightwell G
Introduction In order to understand the emergence, persistence, and transmission of Campylobacter jejuni in livestock, this longitudinal study characterized the C. jejuni population in young calves and assessed the impact of exposure to wild birds during the pre-weaning period. Methods and results Faecal samples were collected on eight occasions from 48 calves housed in three pens between birth and 10 weeks of age, two of the pens being covered with orchard netting. From the 250 C. jejuni isolates obtained from the positive faeces, seven distinct sequence types (7-gene legacy MLST) were identified, with high genetic similarity of circulating strains. On each pen, sequential dominance of ST was observed, with ST-508 and ST-50 prevalent in calves under 4 weeks old, and ST-520 or ST-422 prevalent in the 8- to 10-week-old calves. Exposure of calves to wild birds did not influence genotypes distribution, α-diversity, and community dissimilarity. However, a difference in C. jejuni populations between the two groups of calves that were not exposed to birds suggests that calving rank may shape the type and succession of ST detected over time. Conclusion This study provided no evidence for exposure to wild birds being a driver for C. jejuni population changes in healthy pre-weaned calves.
The evolution of bacterial genome assemblies - where do we need to go next?
(OAE Publishing Inc., 2022-04-12) Altermann E; Tegetmeyer HE; Chanyi RM; Ventura M
Genome sequencing has fundamentally changed our ability to decipher and understand the genetic blueprint of life and how it changes over time in response to environmental and evolutionary pressures. The pace of sequencing is still increasing in response to advances in technologies, paving the way from sequenced genes to genomes to metagenomes to metagenome-assembled genomes (MAGs). Our ability to interrogate increasingly complex microbial communities through metagenomes and MAGs is opening up a tantalizing future where we may be able to delve deeper into the mechanisms and genetic responses emerging over time. In the near future, we will be able to detect MAG assembly variations within strains originating from diverging sub-populations, and one of the emerging challenges will be to capture these variations in a biologically relevant way. Here, we present a brief overview of sequencing technologies and the current state of metagenome assemblies to suggest the need to develop new data formats that can capture the genetic variations within strains and communities, which previously remained invisible due to sequencing technology limitations.