Government researchers sound alarm over spraying antibiotics on FL citrus

May 28, 2019 7:00 am

If you drive by an orange grove these days and see someone spraying the trees, it may be antibiotics in that mist. They are spraying streptomycin and oxytetracycline – antibiotics often used on people.

The Trump administration in December gave the go-ahead for agricultural operations to spray antibiotic pesticides on nearly a half-million acres of Florida citrus, despite warnings from scientists and government health officials that it could increase the problem of antibiotic resistance in people and in the air, water, and soil. Antibiotic pesticides have been sprayed in Florida before, but this scale is unprecedented (see the Phoenix’s previous report: Don’t want antibiotics sprayed on your citrus? Sorry – it’s about to expand, big-time).

Now, newly uncovered documents show that researchers at the U.S. Centers for Disease Control – the federal agency that deals with America’s public health and disease outbreaks – concluded two years ago that spraying streptomycin and oxytetracycline is tied to antibiotic resistance in bacteria that cause serious health threats – including the MRSA, CRE and VRE infections.

The most alarming finding of the Centers for Disease Control’s study is that when antibiotic pesticides are sprayed on bacteria (in soil, water, air and on trees and fruit), the bacteria can pass the resistance to other bacteria, and then that resistance can adapt to “one or more unrelated antibiotics used to treat infections.”

The Centers for Disease Control produced the damning 2017 report and then the U.S. Environmental Protection Agency provided only a summary of the findings when it approved the expanded antibiotic spraying two years later (it brings to mind Attorney General William Barr’s controversial “summary” of the Robert Mueller report).

The only reason we know about the Centers for Disease Control’s troubling findings is because a science group called the Center for Biological Diversity made a Freedom of Information Act request and got the full 2017 study by the Centers for Disease Control. Before that, all that was public was the EPA summary.

“The EPA has had this information,” says Nathan Donley, senior scientist with the Center for Biological Diversity. In the EPA’s summary, “they left out the most damning one, which is that exposure to streptomycin and oxytetracycline can facilitate the development of resistance to other, more important, antibiotics.”

Adam Putnam was Florida’s Agriculture Commissioner when Florida made the request to expand antibiotic spraying. Citrus growers were clamoring for the approval because the antibiotic pesticides – which they were already using on a more limited basis – seemed to be the only thing working to curb the damage from a plant disease called citrus greening that’s ravaging groves and devastating the industry. Plant scientists are working to develop citrus strains resistant to the disease, but for now, they say the antibiotic pesticide spraying is the last hope.

When the EPA approved expanded use of the antibiotic pesticides, EPA scientists expressed concern, but ultimately ruled that the economic benefits outweighed the EPA’s warnings about potential harm to the environment, people, and wildlife.

It’s unclear how much of the antibiotics – sprayed on leaves and taken up into a plant’s vascular system – will end up in fruit; it’s never been sprayed on this scale before. The government relied on the citrus industry to do its own tests, and the industry reported low antibiotic residues on fruit. The U.S. Department of Agriculture (which, worth noting, is not a public health agency) asserts that the amount of antibiotic exposure to people who eat fruit or juices is far less than what people are exposed to when their doctor prescribes antibiotics.

Nikki Fried is the new Florida Agriculture Commissioner, and her spokesman, Max Flugrath, says in a statement: “The EPA approved this request on emergency usage for growers who have been struggling to protect their crops from citrus greening. The rules governing usage are based on several safety standards — including preventing harmful bacterial resistance.”

“The purpose of these rules is to protect crops while avoiding negative health and environmental effects. This approach to take on citrus greening is just one of many tools for growers to protect Florida’s citrus.”

One strategy that agricultural officials and growers plan to try is to “cycle” between different antibiotics in hopes of thwarting antibiotic resistance. But many independent scientists, including the group Keep Antibiotics Working, say there isn’t good science to show that would work.

Another concern is that the antibiotics will affect bees, which pollinate citrus flowers, as well as small mammals. In the environment, antibiotics can change the chemistry of soil and water, knocking ecosystems out of balance.

And how will the spraying affect farm workers who tend and harvest Florida’s citrus? Advocates are worried. Each year in the U.S., at least two million people are infected with antibiotic-resistant bacteria, and at least 23,000 people die, the Centers for Disease Control reports. The agency calls antibiotic resistance “one of the world’s most urgent public health problems.”

“Many medical advances are dependent on the ability to fight infections using antibiotics, including joint replacements, organ transplants, cancer therapy, and treatment of chronic diseases like diabetes, asthma, and rheumatoid arthritis,” the Centers for Disease Control warns.

“Antibiotic resistance does not mean the body is becoming resistant to antibiotics; it is that bacteria have become resistant to the antibiotics designed to kill them,” the Centers for Disease Control says.

Is this risky environmental and public health experiment worth it? Citrus growers would say yes. The pesticide industry would say yes. But it’s worth asking Florida’s Department of Agriculture to take a second look and answer a key question: Is this a case where the cure may be worse than the disease?

Here, for the record, are the four relevant points from the Centers for Disease Control study unearthed by the Freedom of Information Act request:

“1. Resistance to the pesticides is found in bacteria causing human disease

2. Resistance to the pesticides is often conferred by acquired resistance mechanisms that are known to be transferable from one bacteria to another.

3. Pesticides can select for resistance to related antibiotics (i.e., cross-resistance)

4. Pesticides can select for bacteria that are resistant to one or more unrelated antibiotics used to treat infections (i.e., co-selection of resistance). This includes selection for eRE bacteria that have been identified as an urgent AR (antibiotic resistance) threat, as well as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus which have been identified as serious AR (antibiotic resistance) threats.”

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Julie Hauserman
Julie Hauserman

Julie Hauserman has been writing about Florida for more than 30 years. She is a former Capitol bureau reporter for the St. Petersburg (Tampa Bay) Times, and reported for The Stuart News and the Tallahassee Democrat. She was a national commentator for National Public Radio’s Weekend Edition Sunday and The Splendid Table . She has won many awards, including two nominations for the Pulitzer Prize. Her work is featured in several Florida anthologies, including The Wild Heart of Florida , The Book of the Everglades , and Between Two Rivers . Her new book is Drawn to The Deep, a University Press of Florida biography of Florida cave diver and National Geographic explorer Wes Skiles.