Dust from the cattle feedyard carries antibiotics, antibiotic resistance genes, and bacteria according to a recent study out of Texas Tech. More specifically, airborne dust containing antibiotic resistance genes for tetracycline resistance, cattle fecal bacteria and even antibiotics used in cattle were detected downstream of cattle feedlots, which housed tens of thousands of cattle.
Bacteria can be found everywhere, even in clouds, so the fact that bacteria, and any resistance genes they harbor, are hitching a ride on the dust particles from the feedlot isn't surprising.
So what does that have to do with leafy greens?
Well, a recent USDA study found that E. coli, including the pathogen E. coli O157:H7, can also be carried away from the feedlot in airborne dust. The scientists even found E. coli, including E. coli O157:H7, in leafy greens that had been planted at increasing distances away from the feedlot. All leafy green plots were contaminated, even those planted farther than the recommended distance by the USDA as a safe set-back distance for fresh produce when planted around high density feedlots.
What it looks like is that airborne feedlot dust has the potential to spread antibiotics, antibiotic resistant bacteria, and pathogens beyond the feedlot and to the surrounding environment including the nearest leafy green and maybe even neighboring communities. As we have mentioned before, some studies have shown increased exposure to and even infections due to antibiotic resistant bacteria in rural communities that are located close to high density livestock operations.
These new studies illustrate how antibiotic resistant bacteria can and do escape the feedlot and again call attention to the importance of using antibiotics both judiciously and sparingly in animal agriculture in order to protect public health. Because the misuse of antibiotics in the feedlot can lead to antibiotic resistant bacteria not only in the main course, but also in the side salad.