Antibiotic resistance is a big problem, in the human as well as the animal world. In fact, research has indicated that up to eight percent of β-Hemolytic Streptococcus (BHS) infections in animals are resistant to antibiotics like penicillin, which is the go-to treatment for BHS infection in humans.

But veterinary microbiologists like Kelli Maddock, a USF College of Public Health DrPH student in the clinical laboratory science and practice concentration, wonder if those numbers represent true antibiotic resistance or are the result of a lack of standardized testing among labs. 

She and her colleagues explore the issue in the paper “β-Lactam resistance in veterinary β-hemolytic Streptococcus species: Are we experiencing a public health or test method crisis?” recently published in the Journal of the American Veterinary Medical Association.

“I personally think we’re experiencing a test-method crisis rather than a public health one because we know the test methods were being performed incorrectly across the country,” said Maddock, whose future career goals include research that considers both animal and human health as well as acting as a bridge between human and animal medicine. “Manufacturer instructions can be confusing, and the standards change periodically. We want testing to be the same across the country for every laboratory that uses a particular test method. Consistency between labs is important because if we change the way we perform a test from prescribed test methods, it may falsely make a bacterium look more or less resistant to antimicrobials. Consistency should get us closer to the truth.”

What can be done to get labs to use standardized testing methods? Communication between test manufacturers and the labs that perform the tests is key, said Maddock.

“We need to work with partners nationally to ensure that we are communicating the importance of consistently performing test methods the way the manufacturer and Clinical and Laboratory Standards Institute standards require,” Maddock noted. “I also think follow-up research comparing different test methods is warranted, too.”

Maddock also commented that while her research is focused on animals, the findings could potentially have human implications.

“Research such as this draws attention to the One Health nature of animal disease,” she said. (One Health, according to the Centers for Disease Control and Prevention, is a transdisciplinary approach to science that recognizes the health of people is closely connected to the health of animals and the shared environment in which we all live.) “I hope it will further emphasize that we have to look at animal pathogens from a One Health lens and that although our testing is done on animals, results may impact humans. Differing resistance trends might suggest that we have to improve antimicrobial prescribing practices, or in our case, make sure that our test methods are being performed correctly.”

Story by Donna Campisano, USF College of Public Health