November 22, 2019
University of Copenhagen The
Faculty of Health and Medical Sciences
Researchers have found a new
survival mechanism for a commonly known type of bacteria. It can send out
warning signals and thus make sure that other bacteria escape 'dangers' such as
antibiotics. The researchers hope that the new knowledge can be utilized to
make antibiotic treatment more effective.
A bacterial infection is not
just an unpleasant experience -- it can also be a major health problem. Some
bacteria develop resistance to otherwise effective treatment with antibiotics.
Therefore, researchers are trying to develop new types of antibiotics that can
fight the bacteria, and at the same time trying to make the current treatment
with antibiotics more effective.
Researchers are now getting
closer to this goal with a type of bacteria called Pseudomonas aeruginosa,
which is notorious for infecting patients with the lung disease cystic
fibrosis. In a new study, researchers found that the bacteria send out warning
signals to their conspecifics when attacked by antibiotics or the viruses
called bacteriophages which kill bacteria.
"We can see in the
laboratory that the bacteria simply swim around the 'dangerous area' with
antibiotics or bacteriophages. When they receive the warning signal from their
conspecifics, you can see in the microscope that they are moving in a neat
circle around. It is a smart survival mechanism for the bacteria. If it turns
out that the bacteria use the same evasive manoeuvre when infecting humans, it
may help explain why some bacterial infections cannot be effectively treated
with antibiotics," says researcher Nina Molin Høyland-Kroghsbo, Assistant
Professor at the Department of Veterinary and Animal Sciences and part of the
research talent programme UCPH-Forward.
One United Organism
In the study, which is a
collaboration between the University of Copenhagen and the University of
California Irvine, researchers have studied the growth and distribution of
bacteria in petri dishes. Here, they have created environments that resemble
the surface of the mucous membranes where an infection can occur -- as is the
case with the lungs of a person with cystic fibrosis.
In this environment,
researchers can see both how bacteria usually behave and how they behave when
they are affected by antibiotics and bacteriophages.
"It is quite fascinating
for us to see how the bacteria communicate and change behaviour in order for
the entire bacterial population to survive. You can almost say that they act as
one united organism," says Nina Molin Høyland-Kroghsbo.
Possibility of Blocking
The Pseudomonas
aeruginosa bacteria are such a big problem that they are found in the top
category 'critical' in the World Health Organization's list of bacteria, where
new types of antibiotics are most urgently needed. Therefore, the researchers
are excited to make new discoveries about the ways in which this type of
bacteria behaves and survives.
"Infections with this
type of bacteria are a major problem worldwide with many hospitalisations and
deaths. That is why we are really pleased to be able to contribute new
knowledge that can potentially be used to fight these bacteria," says Nina
Molin Høyland-Kroghsbo.
However, she emphasises that
it will still take a long time for the new knowledge to result in better
treatment. The next step is to research how to affect the bacteria's communication
and warning signals.
"This clears the way for
the use of drugs in an attempt to prevent that the warning signal is sent out
in the first place. Alternatively, you could design substances that may block
the signal from being received by the other bacteria, and this could
potentially make treatment with antibiotics or bacteriophage viruses more
effective," concludes Nina Molin Høyland-Kroghsbo.
The study is supported by the
Lundbeck Foundation.
Story Source:
Materials provided by University of Copenhagen
The Faculty of Health and Medical Sciences. Note: Content may be
edited for style and length.
Journal Reference:
Julia C. van Kessel. PQS
Signaling for More than a Quorum: the Collective Stress Response Protects
Healthy Pseudomonas aeruginosa Populations. Journal of Bacteriology, 2019;
201 (23) DOI: 10.1128/JB.00568-19
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