1. Antibiotic Resistance on Factory Farms
Devon Byrne

2. Overview… Conditions of factory farms - why do they use antibiotics?
How does bacteria become resistant?
How do humans get it?
Human health consequences
Direct effects on the environment
What is being done?

3. Factory Farms
Antibiotics are injected or orally administered to animals
Animals routinely given antibiotics to
promote growth
prevent diseases (unsanitary, stressed, crowded conditions)
treat infections

4. Factory Farms and Antibiotics
The same antibiotics used in factory farms are used on humans
penicillin, tetracycline, erythromycin, etc.
Antibiotics kill the non-resistant bacteria and leave behind the resistant bacteria to multiply
Resistant bacteria multiply in the animal
Bacteria ready to be passed on to humans

5. Misuse and Overuse
In conventional agriculture, antibiotics are considered food additives, not drugs, and can be purchased “over the counter”
~90% of all veterinary drugs are administered without professional consultation or approval
~70% of antibiotics used in U.S. are fed to factory farmed animals (cattle, poultry, pigs)
Globally, half of all antibiotics are used towards agriculture

6. So what’s the problem??
"Antibiotic resistance is an inevitable consequence of [antibiotic] use, the more you use them the more resistance you will get.”
- Associate Professor Collignon

7. Resistant Bacteria Bacteria can be…
naturally resistant or
acquire a genetic mutation that resists antibiotics
Resistant bacteria produces enzymes that can…
inactivate antibiotic
alter antibiotic target site

9. How do humans get the resistant bacteria?
Direct contact with animals
Infected farms workers can then pass the resistant bacteria onto others
Drinking contaminated water
Manure can leak from factory farm lagoons into groundwater and waterways
Eating under cooked meat
Transfer of genes between animal and human bacteria

11. Human Health Consequences
Children and people with weakened immune systems are most vulnerable
Superbugs
Food borne pathogenic (disease-causing) bacteria (Salmonella, Campylobacter, Enterococcus) are becoming increasingly resistant to classic antibiotic treatments

12. Fluoroquinolone-resistant Salmonella (ERS)
Baytril, an antibiotic used in poultry, similar to human drug, Cipro, used to treat urinary tract infections, food poisoning
Resistance to Cipro has increased 21% since its approval for use in poultry production in 1995
FDA believes ~5000 people affected annually by resistant salmonella

13. MRSA: Methicillin-resistant Staphylococcus aureus
Staph infection that doesn’t respond to antibiotics
Causes skin infections that can spread throughout body (potential to be life threatening)
Common in hospitals, but now showing up more in community settings
According to a European study, community-aquired cases of MRSA can be attributed to factory farms
Responsible for ~19,000 US deaths in 2005
May surpass death toll from AIDS

14. Direct Effects on Environment
Factory farm runoff contaminated with antibiotics
Remaining in environment for long periods of time
Disrupts the natural balance of bacteria
Resistant strains outweigh nonresistant
Antibiotics easily carried by wind and water
“The biosphere is a diluted solution of tetracycline” - Stanley Falkow (Prof. of Microbiology at Stanford School of Medicine)
Effects uncertain

15. What is being done to keep antibiotics working?
1978: FDA begins to express concern but overpowered by producers and pharmaceuticals
2003: McDonald’s pledges to only buy poultry not routinely given antibiotics for growth purposes
2006: EU bans adding antibiotics to animal feed for growth purposes
2007: Preservation of Antibiotics for Medical Treatment Act (U.S.)
“phase out feeding food animals massive quantities of antibiotics important in human medicine”

16. What can we do? Cook meat thoroughly in order to kill bacteria
Eat meat that is antibiotic free
Don’t eat meat at all
Wash your hands to avoid passing on bacteria

17. References
APUA. "Antibiotics in the Ecosystem." Alliance for the Prudent Use of Antibiotics Dec <
Australian Broadcasting Company. "How bacteria become resistant." Millenium Bugs Dec <
Lewis, Ricki. "The Rise of Antibiotic-Resistant Infections." US Food and Drug Adminstration. 8 Dec <
Millman, Suzanne. "The Emerging Threat of Antibiotic Resistance: A Hidden Cost of Factory Farming." Spring Dec <

18. References Continued…
Mlot, Christine. "Antibiotic Resistance." Controversies in Science and Technology : From Maize to Menopause. Ed. Daniel Kleinman, Jo Handelsman and Abby J. Kinchy. New York: University of Wisconsin P, 2005.
Truant, Patti. "Agricultural Use of Antibiotics Prompts Human Health Concerns: FDA Bans Controversial Poultry Drug." MedScape Today. 6 Jan WebMD.8 Dec <
Union of Concerned Scientists. "European Union Bans Antibiotics for Growth Promotion." Food & Agriculture. 14 Feb Dec <
World Health Organization. "Use of antimicrobials outside human medicine and resultant antimicrobial resistance in humans." Media Centre. Jan Dec <

19. Questions?