10. The Race to Find Novel Antibiotics Produced by Bacteria from Horse Stalls

The Race to Find Novel Antibiotics Produced by Bacteria from Horse Stalls

Jessica Hallett, Julie Torruellas Garcia, Ph.D.
Nova Southeastern University

Antibiotics are key in the prevention and treatment of bacterial infections within human and animal populations. The overuse of antibiotics has resulted in increasing cases of antibiotic resistant infections, rendering the current antibiotic selection ineffective. Several antibiotics in use today were initially discovered from soil microbes. Some racehorses receive a variety of antibiotics, including Metronidazole and Oxytetracycline, which target abscesses that erupt within the hoof of the horse. The connection between the manure of the horse to the soil as well as the hoof to the soil provides connections between the antibiotics given to the horse and the bacteria within that soil. The purpose of this research is to examine soil bacteria from racehorse stalls to: 1) discover novel antibiotics and 2) determine if more antibiotic resistance is detected in stalls of horses taking antibiotics. Soil samples were collected from stalls of Standardbred racehorses at Pompano Park Racetrack who have been treated daily with antibiotics and those who haven’t. The soil samples were diluted and transferred to tryptic soy agar plates containing cycloheximide to inhibit fungal growth. Soil bacteria isolates were tested for antibiotic activity against ESKAPE pathogen alternatives using a co-culture method. Soil bacteria isolates were also tested for antibiotic resistance using the Kirby Bauer Disk Diffusion method with six different antibiotics. Preliminary results suggest that the soil from within the stalls of horses receiving daily antibiotics showed greater antibiotic production and greater antibiotic resistance compared to the soil from within the stalls of horses not receiving daily antibiotics.