Antibiotics in agriculture and the risk to human health: how worried should we be?

Abstract

The use of antibiotics in agriculture is routinely described as a major contributor to the clinical problem of resistant disease in human medicine. While a link is plausible, there are no data conclusively showing the magnitude of the threat emerging from agriculture. Here, we define the potential mechanisms by which agricultural antibiotic use could lead to human disease and use case studies to critically assess the potential risk from each. The three mechanisms considered are as follows 1: direct infection with resistant bacteria from an animal source, 2: breaches in the species barrier followed by sustained transmission in humans of resistant strains arising in livestock, and 3: transfer of resistance genes from agriculture into human pathogens. Of these, mechanism 1 is the most readily estimated, while significant is small in comparison with the overall burden of resistant disease. Several cases of mechanism 2 are known, and we discuss the likely livestock origins of resistant clones of Staphylococcus aureus and Enterococcus faecium, but while it is easy to show relatedness the direction of transmission is hard to assess in robust fashion. More difficult yet to study is the contribution of mechanism 3, which may be the most important of all.

Overview: Global and Local Impact of Antibiotic Resistance

“…23 Most of this usage is not for treating disease in animals (livestock) but for growth promotion and disease prevention, usually at subtherapeutic concentrations. Chang and colleagues 24 have suggested 3 mechanisms by which AR in agriculture could threaten human health: (1) a human is infected by a resistant pathogen through contact with livestock or through ingestion of bacteria from contaminated food or water; (2) a human becomes colonized by resistant bacteria through one of these means, then spreads it to another person who subsequently becomes ill; (3) resistance genes arising in agriculture are spread to humans through horizontal gene transfer and the resulting resistant strains are selected by antibiotic use in people. Evidence suggests several strains of …”

Impact of Rectal Swabs on Infectious Complications after Transrectal Prostate Biopsy

“…It is also notable that 41.2% of the patients with no past history of quinolone use showed resistance to this antibiotic. The indiscriminate use of antibiotics for the treatment of urinary tract disorders and other conditions, and the use of antibiotics in food products may be factors contributing to resistance [34]. …”

IgYs as an Alternative Approach to Antibiotics

“…Bacteria can be transferred between all of them through contaminated vegetables, meat, sewage, manure or by direct contact with infected animals or people. [17,[28][29][30]. Therefore, farms and hospitals should be considered as places of increased risk.…”