According to new University of Queensland (UQ) study, a key ingredient in common antidepressants such as Prozac could be causing antibiotic resistance. So not only is the bacteria’s increasing resistant to antibiotics caused by the overuse of antibiotics but now it looks like non-antibiotic medications can play a significant role too.
The research, led by Dr. Jianhua Guo from UQ’s Advanced Water Management Centre, focused on fluoxetine a selective serotonin reuptake inhibitor (SSRI), and the key ingredient in antidepressants such as Prozac and Sarafem. These prescription drugs are used to help people recover from depression, obsessive-compulsive disorder, or eating disorders.
Dr. Guo explains that overuse and misuse of antibiotics are generally considered the only major factor contributing to the creation of superbugs. This is because researchers were often unaware that non-antibiotic pharmaceuticals could also cause antibiotic resistance. That is why he initiated the study, to demonstrate that it’s not just antibiotics that are triggering the rise of the superbug. The study is published in Environment International.
Engineer Jianhua Guo of the University’s Advanced Water Management Centre, said:
Our previous study reported that triclosan, a common ingredient in toothpaste and hand wash can directly induce antibiotic resistance. We also wondered whether other non-antibiotic pharmaceuticals such as fluoxetine can directly induce antibiotic resistance.
The Study
- First, the scientists exposing the bacterium Escherichia coli (or E. coli) to different concentrations of fluoxetine (commonly known as Prozac), in body-temperature baths that were changed daily for 30 days.
- Next, the mutated bacteria were transferred to agar plates that contained an antibiotic.
The Results
- These bacteria had a significantly increased resistance to antibiotics chloramphenicol, amoxicillin and tetracycline – up to 50 million-fold compared to the control.
- The stronger the concentration of fluoxetine, the faster the bacteria mutated over time.
- Isolated mutant bacteria with a resistance to one of those antibiotics was also found to show multiple resistances against fluoroquinolone, aminoglycoside, β-lactams, tetracycline, and chloramphenicol.
Dr. Guo said:
Fluoxetine is a very persistent and well-documented drug in the wider environment, where strong environmental levels can induce multi-drug resistance. This discovery provides strong evidence that fluoxetine directly causes multi-antibiotic resistance via genetic mutation, based on a laboratory study using E.coli as a model microorganism.
Up to 11 % of the fluoxetine dose that a patient takes travels through the body unchanged, and enters the environment via the sewer system after the patient urinates it out.
All of this does not mean that people on the medication should stop taking it. For many people, fluoxetine is a fantastic life-saving medication. Furthermore, this study was conducted in the lab. How the drug impacts the microbiome inside the human body is yet to be investigated.
Researcher Min Jin said:
[Fluoxetine] has previously been an invisible factor in the spread of antibiotic resistance, but we should consider this a warning. Further work is required to investigate effects of fluoxetine on antibiotic resistome in human gut microbiota.
Next, the researchers plan to look into finding what other non-antibiotic drugs could be having a similar effect. It is a crucial subject to research because a 2016 study estimated that by 2050, antibiotic-resistant superbugs would be killing 10 million people per year. At the moment, antimicrobial resistance is a significant threat to public health globally, with approximately 700,000 people a year dying from antimicrobial-resistant infections. The researchers need to find all the things causing it and find a way to fix it.
