Abstract
Cultured macrophages are frequently used to investigate Salmonella-host
interactions on a population scale. However, in recent years it has been
shown that sub-populations of intracellular Salmonella develop during
infection (Dr. Helaine and co-workers). Specifically, a high level of intracellular
persister bacteria was reported. These results show that Salmonella
undergo adaptive changes in response to the host-environment at a regulatory
single-cell level; however, the extent to which individual Salmonella
sub-populations adapt at a genetic level remains to be investigated.
Here we have investigated genetic changes of Salmonella in response to
brief exposures to the host environment, and in particular investigate genetic
adaptation within the persister population. Macrophages were infected
with Salmonella bacteria for 30 minutes. Persister bacteria were isolated and
cultured for a new round of infection. For every round we observed a gradual
increase in the number of persister-bacteria isolated from the macrophages.
After 7 rounds, we randomly picked 6 isolates and subjected these to
WGS. The six isolates were clonal harboring the same 5 mutations. One mutation
was an in-frame 15 bp deletion resulting in a 5 amino acid shortening
of a conserved protein. This deletion is also observed in genomes of clinical
Salmonella isolates.
Another mutation was a 161 bp deletion fusing two genes of an operon inframe
resulting in expression a larger protein. The novel fusion protein is
essential for infection and elicits increased persistence towards ampicillin.
In conclusion, during brief exposures to the host environment Salmonella
acquire distinct patho-adaptive mutations.
interactions on a population scale. However, in recent years it has been
shown that sub-populations of intracellular Salmonella develop during
infection (Dr. Helaine and co-workers). Specifically, a high level of intracellular
persister bacteria was reported. These results show that Salmonella
undergo adaptive changes in response to the host-environment at a regulatory
single-cell level; however, the extent to which individual Salmonella
sub-populations adapt at a genetic level remains to be investigated.
Here we have investigated genetic changes of Salmonella in response to
brief exposures to the host environment, and in particular investigate genetic
adaptation within the persister population. Macrophages were infected
with Salmonella bacteria for 30 minutes. Persister bacteria were isolated and
cultured for a new round of infection. For every round we observed a gradual
increase in the number of persister-bacteria isolated from the macrophages.
After 7 rounds, we randomly picked 6 isolates and subjected these to
WGS. The six isolates were clonal harboring the same 5 mutations. One mutation
was an in-frame 15 bp deletion resulting in a 5 amino acid shortening
of a conserved protein. This deletion is also observed in genomes of clinical
Salmonella isolates.
Another mutation was a 161 bp deletion fusing two genes of an operon inframe
resulting in expression a larger protein. The novel fusion protein is
essential for infection and elicits increased persistence towards ampicillin.
In conclusion, during brief exposures to the host environment Salmonella
acquire distinct patho-adaptive mutations.
| Originalsprog | Engelsk |
|---|---|
| Publikationsdato | 2018 |
| Status | Udgivet - 2018 |
| Begivenhed | Copenhagen Bioscience: Averting the Post-antibiotic era - Challenges and developments - Favrholm Campus, Hillerød, Danmark Varighed: 31 okt. 2018 → 3 nov. 2018 Konferencens nummer: 15 http://cph-bioscience.com/en/events/averting-post-antibiotic-era-challenges-developments |
Konference
| Konference | Copenhagen Bioscience |
|---|---|
| Nummer | 15 |
| Lokation | Favrholm Campus |
| Land/Område | Danmark |
| By | Hillerød |
| Periode | 31/10/2018 → 03/11/2018 |
| Andet | Antibiotic resistance among bacterial pathogens is increasing posing serious health threats, and there is therefore a great need to face this challenge. The conference will bring together scientists across several research fields for discussions of possible solutions. It is clear that next generation therapeutic strategies will be rooted in creative multi-disciplinary research performed by the best scientists. Meet some of them at the forth-coming conference from 31 October to 3 November 2018.<br/><br/>Conference topics<br/><br/> Infection mechanisms, treatments and host response<br/> Antibiotic resistance<br/> Microbiomes, infections and resistance<br/> New antibiotics and treatments<br/> |
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