U.S. lawmakers are urging the Environmental Protection Agency (EPA) to rethink its position on the use of two medically important antibiotics to treat a disease affecting citrus production.
In a letter to EPA Administrator Andrew Wheeler, JD, MBA, Rep. Jackie Speier (D-CA) and Sen. Elizabeth Warren (D-MA) said the EPA's proposals to significantly expand the application of oxytetracycline and streptomycin on citrus trees to prevent citrus greening disease—a bacterial infection—will exacerbate the problem of antimicrobial resistance.
The two requested that the agency not authorize expanded use of the antibiotics until it can be determined that such use will not harm human health.
The letter, which was signed by five other lawmakers, also argues that the EPA has ignored other federal agencies and scientific evidence in its decision-making process.
The EPA approved emergency use of the antibiotics on citrus trees in Florida in 2016 to combat the disease, then said it would allow expanded use of oxytetracycline on roughly 700,000 acres of citrus farms in Florida and California in December 2018. The agency is currently reviewing the request for expanded use of streptomycin.
Citrus greening is caused by a bacterium Candidatus Liberibacter asiaticus spread by an insect called the Asian citrus psyllid.
When citrus trees are infected, they produce fruits that are green, small, misshapen, and bitter and can't be sold.
Most infected trees eventually die within a few years.
According to the US Department of Agriculture's Animal and Plant Health Inspection Service, the disease has devastated millions of acres of citrus crops across the United States since 2005.
In Florida, as much as 90% of citrus acreage has been affected.
Seeking protection against the disease, the Florida Department of Agriculture and Consumer Services asked the EPA for permission to spray oxytetracycline and streptomycin on orange trees in 2016, then renewed that request in 2017.
Spraying has not solved the problem, but has slowed the spread of the disease.
The Florida Department of Citrus considers antibiotic spraying to be a short-term response to citrus greening.
The proposals for expanded use of the drugs would allow citrus growers to use 338,000 pounds of oxytetracycline and 650,000 pounds of streptomycin a year.
Those amounts dwarf the amounts of oxytetracycline and streptomycin used in people.
Public health and environmental advocacy groups have expressed concern about widespread application of oxytetracycline and streptomycin to control plant disease, as the drugs are used to treat a variety of human bacterial infections and are considered "highly important" and "critically important" to human health by the World Health Organization.
The concern is that spraying massive amounts of the antibiotics on citrus trees could spur antibiotic resistance in bacteria in the soil, and that resistant pathogens in the soil could ultimately find their way into people and cause drug-resistant infections. ■