Four Routes of Exposure to
Antibiotic-Resistant Bacteria: Medicine, Food, Water, and Air
April 07, 2015
Story at-a-glance
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Antibiotic usage in agriculture rose by 16 percent between
2009 and 2012, and nearly 70 percent of the antibiotics used
are considered “medically important” for humans
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Antibiotics are losing their viability in human medicine due
to drug resistance, and without effective antibiotics, even
minor infections can grow into lethal events
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Food, water, and even air are sources of drug-resistant
disease
By Dr. Mercola
American livestock farmers use nearly 30 million pounds of
antibiotics each year in the raising of their animals.1,2
Most of these are raised in confined animal feeding operations
(CAFOs)—gigantic factory farms that hold many thousands of animals
in a warehouse-style setting.
Overcrowding, lack of sanitation, stress, and an unnatural diet
make CAFO animals prone to illness, and antibiotics are routinely
added to their feed to combat disease. Antibiotics also have the
side effect of promoting growth, making the animals grow fatter,
faster, which is another reason for the drugs' use.
This agricultural use accounts for about 80 percent of all
antibiotics used in the US,3
making it a significant source of continuous low-dose exposure via
your diet.
The best way to avoid this exposure is to buy animal products
that have been raised according to organic standards, which includes
being raised on pasture, as antibiotics are not permitted in organic
farming.
The Hazards of Antibiotic Overexposure
Antibiotic usage in agriculture rose by 16 percent between 2009
and 2012,4
and nearly 70 percent of the antibiotics used are considered
"medically important" for humans. The ramifications of this overuse
are manifold:
- Antibiotics are losing their viability in human medicine due
to drug resistance, and without effective antibiotics, even
minor infections can grow into lethal events
- Food has become a major source of exposure to drug-resistant
disease, which can be lethal
- Antibiotics decimate your microbiome (important
health-promoting bacteria in your gut). An unbalanced microbiome
can contribute to both obesity and chronic disease
A 2013 paper5
by the Center for Science in the Public Interest (CSPI) reports that
between 1973 and 2011, more than half of the 55 antibiotic-resistant
foodborne outbreaks in the US involved pathogens resistant to
five or more antibiotics.
Researchers are now finding that when bacteria develop resistance
to one drug, their ability to develop resistance to other drugs
increases. This is why we're now seeing a growth in multi-drug
resistance, and this can make treating human disease really
difficult.
Four Routes of Exposure: Medicine, Food, Water, and Air...
Ever since antibiotic-resistance began gaining attention, the
focus has been on agricultural overuse (growth promotion) and
medical misuse (such as using antibiotics for viral infections, for
example).
However, additional routes of exposure exist that also need to be
addressed in order to contain the situation. At present, research
has revealed no less than four different sources and routes of
exposure to antibiotic-resistant bacteria:
- Food (both animal products and produce)
- Medicine
- Water (both aquaculture and contaminated wastewater)
- Air (contaminated dust particles)
Contaminated Wastewater: a Breeding Ground for Drug-Resistant
Disease
Forbes Magazine6
recently featured an article on the topic of antibiotic resistance,
noting that drug manufacturers may be significantly contributing to
the problem by flushing out antibiotics with wastewater during the
manufacturing process.
This antibiotic-laced wastewater ends up in rivers, drinking
water, and on agricultural crop lands.
Many drug companies have located their manufacturing facilities
in countries where production costs are low, such as China and
India, and according to Swedish researchers, the amount of drugs
found in drinking water in certain drug processing areas are quite
significant.7
For example, one water treatment plant in Patancheru (near
Hyderabad), India, receives 400,000 gallons of wastewater per day
from 90 different pharmaceutical companies in the area.8
This manufacturing wastewater is combined with domestic wastewater.
As reported by Forbes:
"They found a number of drugs contaminating the water,
some in concentrations higher in the water than in patients'
blood.
The worst was pollutant was ciprofloxacin,
with concentrations up to 31 mg/L and in only one day
totaling '44 kg, which is equivalent to Sweden's entire
consumption over 5 days, or, expressed
in another manner, sufficient to treat everyone in a city with
44 000 inhabitants.'
These researchers also found that the effluent was toxic
to many organisms, and that it promoted resistance genes.9
Almost two percent of DNA samples from downstream sites sampled
had resistance genes.10"
[Emphasis mine]
Ciprofloxacin (Cipro) is a fluoroquinolone antibiotic—a class of
synthetic antibacterial drugs that directly inhibit bacterial DNA
synthesis. Several drugs in this class have been taken off the
market due to their deadly adverse effects.
Due to their tremendous health risks, fluoroquinolones should be
reserved for treating serious bacterial infections
that will not respond to any other treatment. The idea that Cipro is
being disseminated at those levels into the environment, and
people's drinking water, is disconcerting to say the least.
Aside from direct ingestion, contaminated wastewater also ends up
on crop fields via irrigation and sludge (biosolids)
used as fertilizer. In this way, drug resistant genes are spread,
shared, and multiplied throughout the environment.
And there does not appear to be any way to contain it. According
to a 2008 CDC report,11
E.coli bacteria resistant to multiple drugs have even been found in
the Arctic; brought there by migrating birds.
Fish Farms—Another Water-Borne Source of Antibiotic-Resistance
The same problems that are occurring on land are now also
occurring in the sea, with
farmed fish becoming another major outlet for antibiotic usage.
Unlike land animals, fish are not fed the antibiotics for growth
promotion but rather for disease prevention.
Industrial fish farming, or aquaculture, is the fastest growing
form of food production in the world, nearly tripling in the last
two decades. About half of the world's seafood now comes from fish
farms, including in the US, and this is expected to continue
increasing.
The close quarters where farmed fish are raised (combined with
their unnatural diets) means disease occurs often and can spread
quickly. On fish farms, which are basically "CAFOs of the sea,"
antibiotics are dispersed into the water, and sometimes injected
directly into the fish.
Unfortunately, farmed fish are often raised in pens in the ocean,
which means that pathogens can spread like wildfire and contaminate
any wild fish swimming past. Antibiotics can also spread to wild
fish via aquaculture and wastewater runoff. In the largest study12
of antibiotics in US seafood to date, researchers detected five
different antibiotics in shrimp, salmon, tilapia, and trout.
Some of the antibiotics detected are also used to treat human
diseases and showed up in wild-caught seafood as well,
likely due to wastewater treatment plant runoff. Even a variety of
farm-raised salmon that was labeled as antibiotic-free was found to
contain antibiotic residues.
And, although the levels detected were low, and within legal
limits, the threat of antibiotic resistance remains. In fact, the
researchers noted that publications reporting antibiotic resistance
in aquaculture have increased eight-fold over three decades, adding
that: "Antibiotics present at levels well below regulatory
limits still can promote the emergence of drug resistant
microorganisms."
How Drug-Resistant Bacteria Spread Via the Air
Researchers at Texas Tech University recently proposed that
antibiotic-resistant bacteria may travel and disperse into the
environment via the air, in the form of contaminated
airborne dust from feedlots.13
As reported by Food Safety News:14
"Scientists collected air samples upwind and downwind of
10 feedlots in the southern High Plains region and found greater
amounts of bacteria, antibiotics and DNA sequences responsible
for antibiotic resistance downwind of the feedlots compared to
upwind. [T]heir findings help characterize how pathogens could
travel long distances to places inhabited by humans."
According to Philip Smith, an associate professor of
terrestrial ecotoxicology at the university’s Institute of
Environmental and Human Health, microbes are “promiscuous with
their genetic information,” and can share their genetic
information across species. What this means is that microbes
that have not been directly exposed to antibiotics may still
develop resistance, simply by coming into contact with
drug-resistant bacteria.
The fact that this mingling may occur just about
anywhere—even out in nature—is troubling, as it implies there’s
virtually no way to stop the progression of resistance. It
simply cannot be confined. Greg Mayer, an associate professor of
molecular toxicology told Food Safety News that “this study is
proof of the principle that antibiotic-resistant bacteria could
plausibly travel through the air.”
What Can Be Done to Curb Antibiotic-Resistance?
At this point, there's no one singular solution. In order to
get a handle on drug-resistant microbes, we need a multi-pronged
approach. A paper15
published in the Environmental Health Perspectives in 2013
provides an overview of management options for reducing the
release of antibiotics and resistant genes into the environment,
which includes:
- Limiting agricultural and aquacultural use of
antibiotics
- Wastewater treatment
- Biosolid treatment, and
- Finding and using alternatives to antibiotics
Not only do we need to control and significantly limit or
eliminate agricultural use of antibiotics, we also need to
improve basic sanitation on a global level. This includes
improving wastewater treatment to filter out drugs. But even
then, the issue remains of what to do with these filtered out
contaminants. Ideally, these drugs should not end up in
wastewater in the first place. Manufacturing processes need to
be revised to prevent antibiotics (and other drugs) from being
flushed out. This would likely necessitate stronger regulations
of industrial waste management, and stronger enforcement of the
regulations currently in place. Individuals also need to be
educated on safer drug disposal, as many will simply flush
unused drugs down the drain.
Ultimately, we need to stop supporting CAFOs and eat less but
higher quality pastured products. More nutrient dense, eggs,
dairy and meat can be savored and are much more satiating. You
may find it surprising, but essential oils have antimicrobial,
antibacterial and antifungal properties, rendering them useful
in various areas of food production. A recent article in The
Atlantic16
discusses the experimental use of essential oils to combat
disease and pests, citing a number of positive studies,
including the following:
- Recent research published in Poultry Science17
found that adding oregano oil to chicken feed resulted in a
59 percent reduction in mortality rate from ascites, a
common infection in poultry
- A 2011 study18
published in BMC Proceedings showed that certain
combinations of plant extracts actually changed the gene
expression of treated chickens, resulting in weight gain and
protection against intestinal infection
- An earlier study19
produced similar findings, using extracts from
turmeric, chili pepper, and shiitake mushrooms
- A 2012 study20
found that rosemary and oregano oils were effective against
pathogenic bacteria. In addition, these oils produced the
same growth rate in chickens as the antibiotic avilamycin
Taking Control of Your Health Is Part of the Solution
Buying organic is, I believe, a crucial step to protecting
yourself, your family, and the environment from undue exposure
to antibiotics and potentially drug-resistant pathogens. This
includes buying grass-fed or pastured animal products, such as
beef, chicken, milk, and eggs. When it comes to seafood, I
recommend avoiding farmed fish and other seafood, and sticking
to wild-caught varieties. While contamination may occur even
there, at least the risk is lower. You can also grow
your own organic vegetables, thereby circumventing exposure to
unknown chemicals and potentially contaminated sludge
fertilizers. Filtering your drinking water is also a good idea.
Unfortunately, those who need water treatment the most are
also among those least likely to be able to afford it; this
includes rural areas in the US, and countries like India and
China where drug manufacturers are significantly adding to the
burden of water contamination. If you live in the US, the
following organizations can help you locate farm-fresh foods
that have been raised in a humane, sustainable manner.
Supporting local farmers—especially those who are switching over
to
regenerative land management practices, and there are
increasing numbers of farmers who are doing just that—will help
promote a cleaner, safer, healthier food system for everyone in
your community.
Weston Price Foundation21
has local chapters in most states, and many of them are
connected with buying clubs in which you can easily
purchase organic foods, including grass fed raw dairy
products like milk and butter. |
Local
Harvest -- This Web site will help you find
farmers' markets, family farms, and other sources of
sustainably grown food in your area where you can buy
produce, grass-fed meats, and many other goodies. |
Farmers' Markets -- A national
listing of farmers' markets. |
Eat
Well Guide: Wholesome Food from Healthy Animals
-- The Eat Well Guide is a free online directory of
sustainably raised meat, poultry, dairy, and eggs from
farms, stores, restaurants, inns, and hotels, and online
outlets in the United States and Canada. |
Community Involved in Sustaining Agriculture
(CISA) -- CISA is dedicated to sustaining
agriculture and promoting the products of small farms.
|
FoodRoutes -- The FoodRoutes "Find Good
Food" map can help you connect with local farmers to
find the freshest, tastiest food possible. On their
interactive map, you can find a listing for local
farmers, CSAs, and markets near you. |
Copyright 1997- 2015 Dr. Joseph Mercola. All Rights Reserved.
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