The Danger of Resistance
The World Health Organization refers to this epidemic as “one of the biggest threats to global health, food security, and development today.” This threat is known as antibiotic resistance. Antibiotic resistance is an evolutionary consequence the comes from using antibiotics. Over time bacteria evolves or mutates and antibiotics can no longer kill pathogenic bacteria. The current stewardship of antibiotics around the world is speeding up the rate of antibiotic resistance. It was said by the inventor of penicillin himself. When Alexander Fleming accepted his Nobel Peace prize he warned, “the public will demand [the drug] …then will begin an era…of abuse” (Fleming, 1945). Antibiotics are being overused on almost every platform. This story will define what antibiotic resistance is and how the food industry is playing a big role in it.
Studies have shown that either treatment indication, choice of agent, or duration of antibiotic therapy is incorrect in 30% to 50% of cases for humans. Patients in the hospital’s ICU are prescribed antibiotics and 30% to 60% of them have been found to be unnecessary and inappropriate. The biggest number of antibiotic use comes from the food industry. An estimated 80% of antibiotics sold in the US are for animals. These antibiotics are given to them to primarily promote growth and to prevent infection.
Biologically, the overuse of antibiotics “clearly drives the evolution of resistance” (Ventola, 2015). Every time an antibiotic is used the chances increase for the bacteria to become resistant in the future. When Alexander Fleming was studying antibiotics, he came to an understanding that some antibiotics bestowed an unfortunate advantage on the bacteria that happen to be already naturally resistant. Antibiotic resistance is a product of natural selection. When a strand of bacteria survives over another, the strand that survived is the one that multiplies. Epidemiological studies found a direct relationship between “antibiotic consumption and the emergence of resistant bacterial strands.” Resistance occurs within the genes of bacteria. These genes can be “inherited from relatives or can be acquired from nonrelatives on genetic elements such as plasmids.” This results in “proliferation of the resistance trait.”
The transfer of resistant genes is happing faster now than it ever has in history. When bacteria transfer their genetic information on a plasmid they do it horizontally. In the past resistance only occurred through mutations. Scientists have learned that bacteria that have never been exposed to an antibiotic can already be resistant to it because their neighbor carries the gene and it was passed on.
Now that we have established what antibiotic resistance is, let me explain how the use of antibiotics in the food industry is not only speeding it up but how it’s dangerous to the environment and our health.
The environmental microbiome is largely affected by the use of agricultural antibiotics in many ways. Up to “90% of the antibiotics given to livestock are excreted in urine and stool.” It is then dispersed through fertilizer, groundwater, and surface runoff. Introducing this amount of antimicrobial compounds to the environment encourages bacteria to become resistant to it.
It was noticed more than 35 years ago that “high rates of antibiotic resistance were found in the intestinal flora of both animals and farmers.” Resistant bacteria in farm animals can reach consumers through meat products. Lee Ventola wrote how this happens in three steps.
- Antibiotics used in food animals kills or suppresses susceptible bacteria, allowing antibiotic-resistant bacteria to thrive.
- Resistant bacteria are transmitted to humans through the food supply.
- Bacteria now has the ability to cause infections in humans that may lead to adverse health consequences.
The overuse of antibiotics in animals invites microorganisms to be apart of the human food chain. If a group of animals is being treated with the same antibiotic over time, the bacteria living in the animal can become resistant to that antibiotic. Microbiologist Dr. Glenn Morris said “the problem for humans is that if a person ingests that resistant bacteria via improperly cooked meat and becomes ill, that person might not respond to antibiotic treatment.
Recent studies have shown direct correlation from using antibiotics on farms to resistant pathogens in the community. In a PBS report, The Trouble With Antibiotics, Joan Casey studied a region of central Pennsylvania that had a high number of swine animal feed operations. Casey was reading research in Europe that connected MRSA from pig farms to people. MRSA is a resistant form of bacteria that can cause deadly skin infections. Casey with the help of Brian Schwartz from Geisinger Medical Center in Pennsylvania conducted a study to see if the same thing was happening in the United States. Dr. Schwarts found that from 2001 to 2009 total MRSA cases have gone up…every year. Total MRSA infections have been rising as much as “34% a year in Central Pennsylvania.” And the people getting infected weren’t the ones you would expect to get it. Young healthy people were suffering from this infection. Joan Casey created a map that shows infected people and swine farms. The people infected with MRSA ended up living very close to swine farms.
Joan Casey and Brian Schwarts created a theory that explains the transmission. Their theory states resistant bacteria is transmitted through manure. About “600 million gallons of animal manure is spread onto crop fields.” This manure is full of undigested antibiotics that are released to the environment. It also contains the genes that bacteria can transfer back and forth that allows them to be resistant. These pathogens can reach the community in two ways. Heavy rains can force the fertilized soil off the farm and land in nearby water run-offs and creaks. High winds can have the same effect by picking up the soil and sending the pathogens airborne.
Soil that is filled with bacteria that is already resistant to antibiotics is problematic because we can no longer treat infections. This throws our society into the pre-antibiotic era again. My next story, Farming With Medicine, shows the time frame on when antibiotics were introduced to the food industry and how the FDA once tried to set restrictions on use.
