Ingredients of
our daily diet – including caffeine – can influence the resistance of bacteria
to antibiotics. This has been shown in a new study by a team of researchers at
the Universities of Tübingen and Würzburg led by Professor Ana Rita Brochado. They discovered bacteria such as Escherichia
coli (E. coli)
orchestrate complex regulatory cascades to react to chemical stimuli from their
direct environment which can influence the effectiveness of antimicrobial
drugs.
In a systematic screening, Brochado’s
team investigated how 94 different substances – including antibiotics,
prescription drugs, and food ingredients – influence the expression of key gene
regulators and transport proteins of the bacterium E. coli, a potential pathogen. Transport proteins function as
pores and pumps in the bacterial envelope and control which substances enter or
leave the cell. A finely tuned balance of these mechanisms is crucial for the
survival of bacteria.
Researchers
describe phenomenon as an ‘antagonistic interaction’
“Our data show that several substances
can subtly but systematically influence gene regulation in bacteria,” says PhD
student Christoph Binsfeld, first author of the study. The findings suggest
even everyday substances without a direct antimicrobial effect – e.g.
caffeinated drinks – can impact certain gene regulators that control transport
proteins, thereby changing what enters and leaves the bacterium. “Caffeine
triggers a cascade of events starting with the gene regulator Rob and
culminating in the change of several transport proteins in E. coli – which in turn leads to a reduced uptake of
antibiotics such as ciprofloxacin,” explains Ana Rita Brochado. This results in
caffeine weakening the effect of this antibiotic. The researchers describe this
phenomenon as an ‘antagonistic interaction.’
“Caffeine triggers a cascade of events
starting with the gene regulator Rob and culminating in the change of several
transport proteins in E. coli –
which in turn leads to a reduced uptake of antibiotics such as
ciprofloxacin.” – Ana Rita Brochado.
This weakening effect of certain
antibiotics was not detectable in Salmonella enterica, a pathogen closely related to E. coli. This
shows that even in similar bacterial species, the same environmental stimuli
can lead to different reactions – possibly due to differences in transport
pathways or their contribution to antibiotic uptake. President Prof. Dr. Dr.
h.c. (Dōshisha) Karla Pollmann emphasizes: “Such fundamental research into the
effect of substances consumed on a daily basis underscores the vital role of
science in understanding and resolving real-world problems.”
The study, which has been published in
the scientific journal PLOS Biology, makes an important contribution to the understanding of what is called
‘low-level’ antibiotic resistance, which is not due to classic resistance
genes, but to regulation and environmental adaptation. This could have
implications for future therapeutic approaches, including what is taken during
treatment and in what amount, and whether another drug or food ingredient –
should be given greater consideration.
Journal article: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003260
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