"Antibiotic-Resistant E. coli and UTIs in Vegetarians vs. Meat-Eaters"
In my video on antibiotic resistance genes, I explored how more
were found in the guts of those who eat meat, dairy, and eggs
than those who eat completely plant-based.
But does the transfer of bacteria from animal foods in the human gut
result in differences in actual clinical outcomes --
other than food poisoning, of course?
Foodborne bacteria sicken about 350 million people every year,
and most of that can be traced to meat, dairy products, and eggs.
Besides food poisoning, though, what about extraintestinal infections,
infections outside the digestive tract, for example, due to pathogenic
and antibiotic-resistant E. coli from retail chicken breasts?
Infections where, though? The urinary tract.
There's a type of E. coli called ST131,
which is a foodborne uropathogen, meaning it causes
urinary tract infections, most of which are just bladder infections,
which typically amount to little more than a painful annoyance,
but can become invasive and spread up into the kidneys
and invade the bloodstream and end your life.
E. coli ST131 emerged explosively in the last 20 years or so
to become the most important multidrug-resistant uropathogen
in circulation today.
Urinary tract infections are caused principally
by ascending E. coli infection via an intestine-stool-urethra route,
meaning these E. coli that cause UTIs, called extra-intestinal
pathogenic E. coli or ExPEC bacteria, start out in the colon,
make it to the anus and then make their way
up into the urethra, then into your bladder.
How do they get into your intestines in the first place?
That's where the chicken comes in.
The role of poultry-meat can be to introduce the ExPEC bacteria,
allowing it to colonize in the rectums of consumers, lying in wait until
an opportunity to cause infection presents itself, for example,
thrusting from sexual intercourse can introduce the bacteria
into the urethra.
The time lag between human ExPEC acquisition in the intestine
and the bladder infection has been the fundamental challenge
linking the two, but we now have strong evidence
that a substantial portion of the ST131 strains
infecting humans originate from poultry.
But they couldn't tell whether any single infection arose
from direct exposure to contaminated poultry or
indirectly from chicken meat from human-to-human transmission
from, say, a partner who ate some contaminated poultry.
What percentage of human UTIs arise from poultry?
Researchers analyzed E. coli isolates from urine samples
from patients with suspected UTIs and compared them to the bacteria
on retail meat samples in the same region,
using DNA fingerprinting techniques.
They found that about a fifth of E. coli isolates from suspected
cases of UTIs belonged to types found in local retail poultry.
21% might not sound like a lot, but E. coli UTIs are one of
the most common infectious diseases in the United States,
affecting approximately seven million women,
so contaminated chicken may result in more than a million UTIs
in American women every year.
This may explain why women infected with multidrug-resistant
E. coli reported more frequent chicken consumption,
putting them at nearly four times the odds,
though frequent consumption of pork was also a risk factor.
Wait. Is it found in pigs, too? Human ExPEC,
those extraintestinal E. coli that cause UTIs, have
also been identified on pig farms, in pigs, and in retail pork meat,
albeit at considerably lower levels than in poultry or chicken meat.
So chicken is riskiest, pork less so, and beef could be considered
the safest from a UTI standpoint, since cattle don't appear
to be a reservoir of these particular types of E. coli.
OK, well, if meat, including poultry and pork, is the major reservoir
for these UTI bacteria, then vegetarians, who avoid meat,
should theoretically suffer less exposure.
However, no study thus far has examined whether vegetarian diets
reduce the risk of UTIs until now:
a prospective study on the risk of urinary tract infection
in vegetarians versus non-vegetarians.
Well, if around 20% are tied to retail chicken meat,
no surprise that eating vegetarian is associated with around
20% lower risk of UTIs, particularly in women.
And this association was independent of diseases
and predisposing risk factors like hypertension, diabetes,
and high cholesterol, meaning it's not just due
to the fact that vegetarians had less diabetes or something.
What about buying organic chicken?
Bacteria swabbed from chicken labeled organic
harbored less antibiotic resistant bacteria, but no --
no less likely to be contaminated with ExPEC UTI bacteria.
These findings suggest that retail chicken products in the United States,
even if they're labeled organic, pose a potential health threat
to consumers because they're contaminated with
extensively antibiotic-resistant E. coli, including the ones
that cause UTIs.
To date only the Jack-in-the-Box E. coli, like O157:H7,
are considered food adulterants,
meaning it's not legal to knowingly sell contaminated meat.
Why don't they do the same with the ExPEC bugs now that
there's such strong evidence they're infecting so many women?
Well, in a survey of retail chicken breasts collected
widely across the United States,
14.3% of the E. coli they found appeared to be ExPEC.
Given that E. coli can be found in about 90%
of retail turkey and chicken products, that would mean
the industry would have to dump
literally billions of pounds of chicken breasts every year.