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T9-03 Prevalence of Extended Spectrum β-Lactamase-producing Bacteria and Escherichia coli O157:H7 on Commercial Beef Cattle Farms in North Florida

Tuesday, August 2, 2016: 2:00 PM
241 (America's Center - St. Louis)
Sarah Markland, University of Florida, Gainesville, FL
Amber Ginn, University of Florida, Gainesville, FL
Raies Mir, University of Florida, Gainesville, FL
Zhengxin Ma, University of Florida, Gainesville, FL
Lin Teng, University of Florida, Gainesville, FL
Choonghee Lee, University of Florida, Gainesville, FL
Darren Henry, University of Florida, Gainesville, FL
Mariana Garcia, University of Florida, Gainesville, FL
Lautaro Rostoll, University of Florida, Gainesville, FL
Nicolas DiLorenzo, University of Florida, Marianna and Gainesville, FL
Chad Carr, University of Florida, Gainesville, FL
Kwangcheol Jeong, University of Florida, Gainesville, FL
Audio File Recorded Presentation
Introduction: According to the Food and Agriculture and World Health Organizations, the primary route of transmission of antibiotic resistant organisms from the environment to humans is through food. It is generally accepted in the scientific community that the emergence of antibiotic resistant bacteria is due to the use of agricultural growth promotors in animal feed however; levels of antibiotic resistant bacteria continue to rise in food-producing animals not previously exposed to antibiotics. 

Purpose: The purpose of this study was to determine the prevalence of extended spectrum β -lactamase-producing (ESBL) antibiotic resistant bacteria and E. coli O157:H7 in animal and environmental sources on commercial cow-calf operations in North Florida. 

Methods: Over 1,000 animal and environmental samples were collected from 17 commercial beef farms across North Florida. ESBL-producing bacteria were enumerated from samples by plating onto MacConkey Agar supplemented with 4 µg/ml of cefotaxime. E. coli O157:H7 was enumerated from samples by plating onto sorbitol MacConkey agar supplemented with cefixime and tellurite. 

Results: The average prevalence of ESBL-producing bacteria and E. coli O157:H7 on farms was 4.3 and 4.0 log CFU/g, respectively. Levels of ESBL producing bacteria were significantly higher in soil samples (P=0.002) and forage samples (P=0.03). Prevalence of E. coli O157:H7 was highest in forage samples with a concentration of 5.6 CFU/g (P=0.01). For both ESBL-producing bacteria and E. coli O157:H7, prevalence was lowest in water samples with a concentration of 1.2 CFU/ml and 0.5 CFU/ml, respectively. 

Significance: These results suggest that transmission of antibiotic resistant organisms to food-producing animals may occur through environmental sources, specifically soil and forage. In addition, emergence of antibiotic resistant bacteria may occur naturally in the environment.

Back to: Technical Session 9 – Meat, Poultry and Eggs
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