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Story at-a-glance -

  • 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
  • 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, water, and even air are sources of drug-resistant disease

Four Routes of Exposure to Antibiotic-Resistant Bacteria: Medicine, Food, Water, and Air

April 07, 2015 | 49,489 views

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:

  1. Antibiotics are losing their viability in human medicine due to drug resistance, and without effective antibiotics, even minor infections can grow into lethal events
  2. Food has become a major source of exposure to drug-resistant disease, which can be lethal
  3. 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:

  1. Food (both animal products and produce)
  2. Medicine
  3. Water (both aquaculture and contaminated wastewater)
  4. 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: Wherever you are, Eat Well -- The Guide is a free online directory of more than 25,000 restaurants, farms, stores, farmers' markets, CSAs, and other sources of local, sustainably produced food throughout the US.
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.

Thank you! Your purchases help us support these charities and organizations.