Researchers from UT-Austin have found that honeybees treated with common antibiotics are half as likely to survive compared to untreated honeybees. Researchers say these findings have health implications for both honeybees and humans.

Integrative biology professor Nancy Moran  and postdoctoral researcher Kasie Raymann led the research team in an effort to understand the bacteria that live inside of the guts of honeybees and how they impact honeybee health.

“To do this, we disrupted the bacteria in the gut using antibiotics to see how it would affect their health and if they were able to recover after they were treated,” Raymann said.

The researchers found that two-thirds of the untreated bees were able to recover after being returned to the hive, while only one-third of the bees treated with antibiotics were able to recover.  

The antibiotics led to a loss of bacteria in the honeybees’ gut, which in turn led to increased infection from diseases to which honeybees aren’t normally susceptible.

“It’s just like in humans,” Raymann said. “When you are given antibiotics, you are more susceptible to getting different bacterial infections, so it seems to be true in bees, too.”

Unlike in other insects, honeybee gut bacteria is transmitted between individuals, a trait common with the human gut environment, Raymann said. She added that the gut bacteria environment is highly conserved, which means honeybees all over the world share most of the same gut bacteria.  

Biochemistry senior and undergraduate researcher Zack Shaffer, also working on the project, said honeybees’ gut bacteria are similar to human gut bacteria, which makes honeybees important to study.

“It is also much easier to study … honeybees since (they have) a much better characterized microbiome, whereas the human microbiome isn’t fully characterized and no one agrees on what the components of it are,” Shaffer said.

However, Raymann said the intention of the study was not to make suggestions about health practices, but instead to add evidence that antibiotics can have significant and often harmful effects on an organism’s preexisting bacteria. 

“These bacteria are very beneficial to you, so disrupting them can have harmful side effects,” she said. “We need to think about how often we are using antibiotics and be a little more cautious with them.”

This discovery is crucial for beekeepers, who faced the disappearance of millions of bees a decade ago, in what is known as colony collapse disorder, according to the Florida Department of Agriculture and Consumer Services. Many factors, such as the use of pesticides, decreases in habitats and bacterial infections were involved in this phenomenon.

Raymann said the researchers cannot necessarily say that antibiotics are a contributing factor in colony collapse since honeybees were not the only species of bees in decline.

“Antibiotic exposure in honey bees could be one thing that we haven’t realized before that could be contributing to death,” she said. “However, there are definitely a lot of other (contributing factors).”

Raymann said a regulation passed by the Food and Drug Administration in January requires that beekeepers contact a veterinarian in order to obtain the antibiotics to treat the hive, a step towards antibiotic regulation.

Raymann said while the bee population is still in decline, the situation seems to be a little better than it was 10 years ago due to the Obama administration’s push in bee mortality research. She said the big question of how to get the bee populations trending upward again remains unanswered.

“We are still really finding out, it seems there are just a lot of different factors affecting decline, and we are not really sure if there is one specific thing,” Raymann said. “Right now it just seems like a combination of a lot of things, so it makes it difficult to figure out how to fix it.”