Researchers claim to show pathway for resistant pathogens

 Resize text         Printer-friendly version of this article Printer-friendly version of this article

A news release from Northern Arizona University (NAU) last week outlines results of a study indicating a food-animal origin for antibiotic-resistance in pathogens, which then jumped to the human population. The study focused on methicillin-resistant Stapylococcus aureus (MRSA) using whole-genome sequencing to study 89 genomes from humans and animals, including turkeys, chickens and pigs, with samples from 19 countries on four continents.

Previous studies, such as from the Centers for Disease Control and Prevention, have shown that pigs can carry the resistant pathogen. The NAU researchers claim their genetic testing has tracked the series of events leading to human MRSA infections.

Their results indicate that humans initially passed the non-resistant Stapylococcus aureus pathogen to food animals. Then, use of tetracycline and methicillin in the animal populations led to the evolution of MRSA in animals. The MRSA pathogen then jumped back to humans, causing staph infections that are difficult to control with traditional antibiotics.

One of the researchers, Paul Keim, Regents’ professor and director of NAU’s Center for Microbial Genetics and Genomics, says the study describes evolution in action. "The most powerful force in evolution is selection. And in this case, humans have supplied a strong force through the excessive use of antibiotic drugs in farm animal production. It is that inappropriate use of antibiotics that is now coming back to haunt us.”

The NAU release received broad coverage in the consumer press last week, and undoubtedly will stoke the fires of the debate over antibiotic use in livestock. Antibiotic opponents will claim the study’s results represent the “smoking gun” showing antibiotic use in livestock created MRSA. Others will point out this is just one study, and that other research has failed to find such a link.

The fact is, antibiotic resistance is a complex subject, and debate likely will continue for years. To help unravel the issue’s complexity and build a dialog, the National Institute for Animal Agriculture (NIAA)  held a symposium last fall titled "Antibiotic Use in Food Animals: A Dialogue for Common Purpose." Following the symposium, NIAA released a White Paper summarizing the science-based presentations from human health and animal health experts who presented information during the symposium.

Comments (7) Leave a comment 

e-Mail (required)


characters left

February, 28, 2012 at 01:59 AM

So not only is the industrial food system making is sick. It's also ... making us sick ?

Dr. Garret Moenk, DVM    
Keosauqua, IA  |  February, 28, 2012 at 03:02 PM

When you look at studies like this one you really need to focus on what the article is saying, not what you think it is saying. The only thing that you can definitively say is that it is possible to transmit S. aureus to and from animals (zoonosis), and that S. aureus is capable of mutating to the resistant form (MRSA). There is no "Smoking Gun" that animal agriculture is the cause of bacterial resistance in humans. That being said, antibiotics are a tool that need to be used responsibly.

Ed Sanchez    
February, 28, 2012 at 09:35 AM

The researcher just as well said we have proven our theory that the source of MRSA is modern livestock production methods based on our interpretation of the so called evidence. When it is duplicated by a reputable scientist I will change my tune.

Texas  |  February, 28, 2012 at 12:20 PM

If we will admit it, we all know that antibiotics are overused in animal agriculture today. We have to change our business practices. The prophylactic use of antibiotics (i.e. in feed and in giving animals antibiotics during arrival "processing" at a feedlot as a "preventative" measure or as a gain improvement tool) having gotten out of control. Use of antibiotics should be reserved and encouraged in sick animals only. Failure to do so puts our entire industry at risk.

Ohio  |  February, 28, 2012 at 03:02 PM

In Human medicine antibiotics are given during or immediately after surgery. How is this different?

WY  |  February, 28, 2012 at 10:22 PM

Does it suprise anyone that experts always find what they're looking for ?

SD  |  February, 29, 2012 at 01:17 PM

Why do some of you ignore the comment by the DVM (Doctor of Veterinary Medicine for those who don't know/care that the man just might be knowledgeable on this subject)? What is the basis for statements that antibiotics are overused in animal ag by the folks making that statement? It is a fact that costs of antibiotics are a factor against overuse. Further fact is that many cattlemen are trained in Beef Quality Assurance, and practice proper practices, directed by qualified veterinarians. And, definitely a player in this 'who to blame' game is the FACT that too many Medical Doctors overprescribe antibiotics for HUMANS, and that too many humans DEMAND they be given antibiotics when they are not needed. Additionally, too many such medications are flushed down toilets when the patient believes he is 'over the illness' before consuming all the medication prescribed!!!

RANGER® Diesel, Sportsman® ATV Series

The Polaris Ranger Diesel sets new standards in terms of efficiency. With its efficient diesel engine, the vehicle is up ... Read More

View all Products in this segment

View All Buyers Guides