Researchers are looking at personalized treatment approaches for post-infectious irritable bowel syndrome (IBS).
- Post-infectious irritable
bowel syndrome (IBS) arises after a person experiences a gastric
infection, such as a norovirus infection, food poisoning, or even
COVID-19.
- Treatments can include
antibiotics and probiotics.
- A team based in Italy
conducted a pilot trial in which they sequenced the gut microbiome of
patients with IBS and used an individualized combination of antibiotics,
prebiotics, and probiotics to treat symptoms.
Patients
treated with a precision approach to post-infectious irritable
bowel syndrome (IBS) reported improved symptoms in a small
cohort of 13 participants with IBS in a pilot trial.
The
researchers conducting that trial analyzed the gut microbiomes — individuals’
“collections” of gut bacteria — of people with the condition, and treated the
overgrowth of certain bacteria with antibiotics,
while also addressing the lack of certain bacterial strains with specific probiotics and prebiotics,
in order to promote a balanced gut environment.
They found that over a third of those treated
in this personalized way experienced complete remission of their symptoms 12
weeks after starting treatment.
Researchers
presented their non-peer-reviewed results at the European
Society of Clinical Microbiology and Infectious Diseases conference held
in Barcelona, Spain from 27-30 April.
Researchers had previously developed testing for stool
samples to detect which strains of bacteria were present in the microbiome of
participants.
They used
this to test the 13 participants and prescribed a specific regime of one of two
antibiotics to treat pathogenic bacteria that existed at levels that were too
high, as well as probiotics to replace beneficial strains that were at levels
that were too low.
Prebiotics
including inulin and psyllium were prescribed to over two thirds of
participants.
At the 12 week follow-up after initiating
treatment, 12 out of 13 participants experienced an improvement in symptoms.
Symptoms
reported before the treatment started were abdominal pain, bloating, diarrhea,
constipation, weight loss and dyspepsia.
After
treatment, the symptoms experienced included abdominal pain, bloating, and
diarrhea. Five participants experienced total remission of symptoms.
The
researchers also reported that gut microbiome testing showed low species
diversity in 23% of participants alongside a high abundance of Proteobacteria in
23% of the cohort, and low abundance of Firmicutes in 38% of them.
Low
abundance of short-chain fatty acid(SCFA)-producing bacteria was found in over
half (54%) of the cohort, low levels of Akkermansia and Bifidobacteria were found in 62%, and 69% of the
cohort respectively.
Study
author Maurizio Sanguinetti, MD, PhD,
professor of medicine and surgery at Università Cattolica del Sacro Cuore in
Rome, Italy, explained to Medical News Today:
“The idea
now is to take into account that this results are quite encouraging up to this
[point] from our point of view, we are starting a sort of randomized trial in
which we use in that group of participants, we use the microbiota-driven
therapy, and in the other group, we use a standard of care.”
IBS is a chronic
condition that affects a person’s digestive system. Symptoms include
recurrent pain, changes to bowel habits.
IBS often
presents with symptoms common in other conditions. For example, people may confuse IBS
with inflammatory bowel disease (IBD).
Where IBS
is a syndrome that does not cause visible damage to the gastrointestinal tract,
IBD refers to a group of diseases, including Crohn’s
disease and ulcerative
colitis, that occur when the immune system attacks
cells in the intestines.
Post-infectious IBS is a form of IBS that
occurs after a person has experienced some kind of gastric upset that was
bacterial or viral in nature, explained Vincent Young MD PhD, professor of
internal medicine and infectious disease at the University of Michigan, who was
not involved in the research.
He told MNT that:
“Basically, most people accept that […] post-infectious IBS is the onset of
symptoms compatible with irritable bowel syndrome that occurs at some period of
time — and that period of time, depending on who’s defining it, can be 2 years
— after you have an infection, and it could be an infection with bacteria, [or]
it could be [with] viruses, such as norovirus or SARS-CoV-2, or [even with]
protozoa.“
The time
frame for when the infection occurred in respect to when the symptoms appeared
was loosely defined, he said.
There is
currently a poor understanding of why some people develop post-infectious IBS
and others do not, explained Satish Rao, MD, PhD, a gastroenterologist and
professor of medicine at the Medical College of Georgia, Augusta University.
Rao, who
was not involved in the current study, explained to MNT that, when we get a gastric infection, the
nociceptive receptors (
“Now, for
most of us, when the illness kind of settles down, these receptors go back to
sleep again, they go dormant again; but for some reason that we don’t understand
yet, in the so-called post-infectious IBS cohort, the nociceptive receptors —
which are pain-sensitive and distension-sensitive — […] don’t go to sleep, they
remain persistently active forever. So that process is called ‘sensitization of
receptors’.”
The
treatment with antibiotics and probiotics the researchers involved in the
current study offered was fairly standard for people with post-infectious IBS,
he said.
As there
were no controls described in the findings presented at the conference, it was
difficult to tell whether or not participants would have responded similarly to
a standardized, rather than personalized, treatment, he added.
“Now, I
don’t know, if patients had had just sort of standard care therapy without
looking at their microbiota, what their response rate would be, […] because
there’s no comparators in this particular case,” said Rao.
Sequencing the microbiome in IBS: Steps forward
Rao said the
research presented at conference was a “step in the right direction,“ adding
that “the only critique [he] would have for this is [that] this [research] is
just a beginning.“
“I’m now
putting on my scientific critical hat here; what we don’t know is: What is the
underlying microbiome or underlying dysbiosis in the colon in these
individuals?” Rao wondered.
He explained that as there is significant
variation between even healthy individuals’ microbiome, it was unclear whether
the dysbiosis — the imbalance between different bacterial strains in the gut —
that occurs in people with post-infectious IBS had caused the symptoms they
experienced.
“[M]y big
problem, really, is how do you […] identify what is missing or what is too much
in an individual’s microbiome?” said Rao.
He added
that people should have their microbiome sequenced when they are healthy in
order for research in this area to advance, and causal factors to be identified:
“[I]f we can get to that stage, I think we will truly practise personalized
medicine, and we can get much better in targeting treatments with some of these
antibiotics, probiotics or prebiotics.”
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