Honeybees and Antibiotic-Resistance Genes

Hannah Ritzman (11 AM Micro) found this following article about off-label use of antibiotics and honeybees. Check out this article from last fall, about the MRSA-fighting abilities of honey. Here is Hannah’s summary:

Honey Bee in Sunlight

Honey Bee in Sunlight (Photo credit: Scott Kinmartin)

A recent article found on ScienceDaily, discusses the bacterial disease called “foulbrood” that honeybees all over the world are susceptible to. This disease has the ability to wipe out a hive faster than beekeepers are able to respond to the infection. In the United States, beekeepers have been using regular preventive applications of the antibiotic oxytetracycline in order to decrease the likelihood of bees contracting the disease. This antibiotic has been used among beekeepers since the 1950s. Mostly due to the decades of preventative antibiotic use in domesticated hives, bacteria in the stomachs of honeybees are now highly resistant to the antibiotic tetracycline. Additionally, it has been found genes resistant to oxytetracycline also are resistant to tetracycline.

A recent study done by Yale University researchers identified eight unique tetracycline resistance genes among United States honeybees that were exposed to the antibiotic oxytetracycline. These resistance genes were absent in bees from countries where antibiotic use is banned. 

Moran and her colleagues examined honeybees from several locations in the United States, Switzerland, the Czech Republic, and New Zealand as well as several wild bumblebees from the Czech Republic, for the presence and abundance of tetracycline resistance genes. Their results were that U.S. honeybees had greater numbers and a more diverse set of tetracycline resistance genes than honeybees from the other countries. The researchers expected a widespread resistance among bees from the United States, especially when considering the decades-long use of oxytetracycline in honeybee hives. Beekeepers have long used oxytetracycline to control the bacterium that causes foulbrood, but the pathogen eventually acquired resistance to tetracycline itself. Of the foulbrood pathogens Melissococcus pluton and Paenibacillus larvae, Moran says, “They carry tetL, which is one of the eight resistance genes we found.”

Switzerland, the Czech Republic, and New Zealand do not allow beekeepers to use oxytetracycline in hives, so it is predictable that honeybees and wild bumblebees from these countries harbored only two or three different resistance genes and only in very low numbers, suggesting that the bacteria did not require the genes very frequently.

The authors of the study point out that by encouraging resistance and altering the bacteria that live in honeybee stomachs, decades of antibiotic applications may have been detrimental to honeybee wellbeing. Studies have suggested that the bacterial residents of the honeybee stomach play beneficial roles in neutralizing toxins in the honeybees’ diet, nutrition, and in defending the bee against pathogens. By disrupting the honeybee microbiota and reducing its diversity, long-term antibiotic use could weaken honeybee resistance to other diseases. Therefore, the treatment that was meant to prevent disease and strengthen the hive may actually weaken its ability to fight off other pathogens.

It is important to note the presence of resistance genes in the honeybee stomach does not pose a direct risk to humans. These bacteria, says Moran, “do not actually live in the honey, they live in the bee. We have never actually detected them in the honey. When people are eating honey, they are not eating these bacteria.”

I found this article to be interesting and relatable to our class discussion about the problem of prescription medications being given in inappropriate situations and too often. This problem is not taking place only among the human population but also the animal population as well.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on November 2, 2012, in Guest Post, Microbes in the News and tagged , , . Bookmark the permalink. 2 Comments.

  1. This article is fascinating and it makes one wonder what type of resistance other animals we pump full of antibiotics, such as cows and chickens, are going to occur. And could these diseases eventually have the potential to infect humans. I was also so glad you mentioned the overuse of antibiotics by people. It is incredible how people run to the doctor for every little sniffle and cough. It is actually annoying and then on top of that demand antibiotics when many times antibiotics are far from needed. I go back to my own life. We did not have a ton of money when I was young and I have a Mom who did not run us to the doctor unless we we bleeding out, I was a bit of a Tomboy, broken, or sick not for a few hours or day but for a few days. She gave our body a chance to work through these things themselves and I could never be more grateful. I rarely get sick and honestly can not even remember the last time I had to go to the doctor for an illness requiring antibiotics. My body is a well oiled antibiotic producing machine itself!!!! I wish more people would think like my Mom and us for that matter, because all people are doing are creating superbugs that are resistant to everything!! And thank you Dr. S for giving me a place to rant about the things that really irritate me.

    • Off label use of antibiotics continue to be a problem in agriculture, directly because of the use of those antibiotics on farm animals. The correct use of antibiotics could also contribute to some of these problems as well, because they do not stay in the human body; we excrete them!. There are measurable levels of antibiotics in wastewater treatment plants, and the combination of human and non-human sources leads to this growing problem. A quick Google search turned up this student research paper from Hartwick College (way up the Susquehanna rivershed in New York) which looked at the contribution of both agricultural and wastewater sources of antibiotics on the levels in streams. And remember, whatever is in the water up there, will be in York, PA in a couple of days!

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