Dr. Lucina Galina, Director of Pork Technical Services Team at Zoetis, talked to The Pig Site’s Sarah Mikesell at the 2022 World Pork Expo held in Des Moines, Iowa, USA. Dr. Galina described Zoetis’ ongoing antimicrobial surveillance of susceptibility in swine pathogens.

“For many years, Zoetis has been conducting antimicrobial surveillance. It is very important for us as a company that manufactures antimicrobials to understand if the pathogens that we're trying to target are susceptible to antimicrobials,” Dr. Galina said. “We have been doing this program for 21 years. We work with all the diagnostic labs in the US and also Canadian laboratories to monitor antimicrobial susceptibility in North America. Then, we report our results in a peer reviewed manuscript; they are reviewed by the scientific community and then we publish the results every five years.”

The Zoetis susceptibility study focuses on about 10 antimicrobials that target pathogens involved with respiratory disease. This is because respiratory disease is the most economically important group of diseases in the swine industry.

“We look at antimicrobial susceptibility for pathogens like Streptococcus suis, Actinobacillus pleuropneumoniae (APP), Mycoplasma hyopneumoniae and Bordetella bronchiseptica, Pasteurella multocida,” she said. “We have found year after year that, overall, most of these pathogens are still highly susceptible to our antimicrobials. For example, if you think about Actinobacillus pleuropneumoniae (APP), they are still highly susceptible to the antimicrobials - cephalosporins, tulathromycin and florfenicol. If you think about Pasteurella multocida, the pathogen has high levels of susceptibility to ceftiofur. Most pathogens have more than 90% susceptibility to these antimicrobials.”

One antimicrobial remains a concern for the industry.

“The one that we have seen more resistance over time is tetracycline. Tetracycline is the one that we have to be very careful about because we see more resistance,” Dr. Galina commented.

However, overall, Dr. Galina continues to see a high level of antimicrobial susceptibility.

“It's very good for us to publish this information and to share this information because it's a very comprehensive national program, and not just a regional program in one diagnostic lab. We cover isolates that we recover from most of the diagnostic laboratories,” she said.

Why is tracking susceptibility important?

“The report tells us we are doing something right. Some of our practices like biosecurity, having people in multi-site locations, and the judicious use of antimicrobials contribute to all of these results and are telling us that we're doing something right as an industry. I'm very proud to be part of that,” she stated.

However, Dr. Galina advises veterinarians to be very careful when making antimicrobial decisions. She reminds that we need to go back and look at the data references through time to determine the right antimicrobial for each pathogen.

“We have those susceptibility reports; we have published that now at the Journal of Swine Health and Production (JSHAP) and also the diagnostic laboratories produce these reports,” Dr. Galina explains. “They can use that as a guide to make the decisions on antimicrobials if they find some that are highly resistant to certain antimicrobials, then we have options. But it's so important that we preserve our options because we don't have very many to choose from, and we still have to take care of our animals. Animals get sick; pigs get sick; we need to have solutions for them,” she concluded.