Minimal evidence of antibiotic resistance in swine

Watch the full interview or each part separately

Minimal evidence of antibiotic resistance in swine

Part 1:  Responsible antibiotic use

Part 2:  Antibiotic reduction: Record keeping is key

Part 3:  Antibiotic surveillance

Data from nearly 2 decades of experience in a large veterinary practice indicate minimal resistant infections in swine, but that will not deter efforts to maximize preventive care and minimize the need for antibiotics, Joel Nerem, DVM, told Pig Health Today.

Nerem, of Pipestone Veterinary Services, pointed to information from the Centers for Disease Control and Prevention that at least 23,000 humans die annually due to antibiotic-resistant infections.¹

“As a veterinarian, I’m concerned about antibiotic resistance, both in treating my patients — pigs, in this case — but also, obviously, as a member of society I’m concerned about antibiotic resistance when it comes to being able to treat infections in human beings.”

As concern about antibiotic use in food animals spilled over into agriculture, Pipestone realized it had years of data from three diagnostic laboratories. It looked at approximately 4,500 cases of infections caused by one of five major swine bacterial pathogens: Streptococcus suis, Haemophilus parasuis, Actinobacillus suis, Escherichia coli and Salmonella. A value of 0 was assigned for bacteria susceptible to a particular antibiotic, and a value of 1 was assigned for resistant bacteria.

Flat line of resistance

Tracked over time, “what we’re finding is a pretty flat line. So that’s good news,” and the findings have largely matched clinical observations, Nerem said.

He attributes the positive results to the pork industry’s proactive approach to making sure the right tools are used in a responsible manner and “making sure that we’re providing a safe and wholesome product for the consumer.”

Nevertheless, concern about antibiotic-resistant infections and the emphasis on responsible antibiotic use have heightened the search for non-antibiotic tools to better promote the health of pigs. There is a lot more that can be done to optimize pig health and performance without relying on antibiotics, Nerem continued.

“We’re big proponents of preventative vaccination; we’re big proponents of the right management techniques to more effectively raise pigs in a healthy environment; we’re all about disease elimination,” he continued.

More pork producers as well as veterinarians are interested in disease elimination versus battling disease with antibiotics. “We like that. We think that’s a good direction to be heading in,” he said. As an example, he cited Mycoplasma hyopneumoniae. Eliminating it from herds will improve the health of pigs, improve profits for producers and reduce the use of antibiotics.

PART surveillance program

Pipestone has also initiated a surveillance program called the Pipestone Antibiotic Resistance Tracker (PART) to help pork producers monitor and track their antibiotic usage over time. It may be the only program out there providing this service to independent farmers, Nerem said.

Through PART, the farm veterinarian reviews the producer’s antibiotic usage every 3 months and submits a report or comments to the producer. At least once yearly, there’s a formal in-person review of the farmer’s data with the veterinarian. Those conversations have led to more discussions about pathogen elimination and alternatives to antibiotics, such as vaccination.

“We think it’s been a big success,” Nerem said, and noted that he’s impressed by the rate of participation. The program has also increased and improved conversations between veterinarians and pig farmers.

Besides increased interest in the elimination of disease, more pork producers are looking for other ways to deliver antibiotics when they are needed. Instead of in-feed, it may be antibiotic treatment by injection or via water, he said, but stressed that “it’s critical that these treatment decisions are being made in conjunction with veterinary consultation through the proper veterinary-client-patient relationship.”

Against arbitrary antibiotic reductions

Nerem stressed that he supports efforts to promote responsible use of antibiotics in food animals. But, he added, “arbitrary reductions in antibiotics at the farm level are not necessarily the most prudent way to approach it, because it might not be the best thing for the pig and the pig’s health. And it might not be the best thing for society as it relates to food safety.”

Pigs get sick and need to be treated. What’s important is making sure the diagnosis is accurate, he said. Clinical skills need to be employed and factors considered such as the age of affected pigs, clinical signs and the number of animals with signs of illness. Sometimes necropsies are needed.

Once all that information is put together, an antibiotic may need to be prescribed. A culture and antibiotic-sensitivity testing are initiated, and by the time results come back in a couple days, the veterinarian will have some impression already about the effectiveness of the treatment prescribed. Usually the results validate the clinical experience. Only sometimes is a change in antibiotic needed, he said.

As for tracking the amount of antibiotics used as a measure of responsible antibiotic use, Nerem acknowledged there was more to assessing responsible antibiotic use that volume. It’s still important to keep track of that information however.  “Our philosophy as it relates to responsible antibiotic use is that we should know how we’re using the drugs we’re using on a farm, and we should keep a record of that,” he added.  “It’s pretty hard to convince people that you’re being responsible with antibiotics if you don’t know how much antibiotics you’re using.”

Pork producers are also concerned about demonstrating their own accountability regarding the responsible use of antibiotics. “All of these folks have families. They are just like you and me, and they want to be able to preserve the effectiveness of antibiotics, not only to treat their livestock but also their family members,” Nerem said.

1. Antibiotic/Antimicrobial Resistance. Centers for Disease Control and Prevention. https://www.cdc.gov/drugresistance/index.html. Accessed November 12, 2019.