For almost 100 years, scientists have fought against antibiotic-resistant microbes. Researchers from Michigan State University have discovered a new strategy to combat this issue by introducing “DNA scavengers” into wastewater treatment facilities.
Syed Hashsham, a professor at MSU specializing in civil and environmental engineering, along with James Tiedje, an esteemed professor emeritus in the departments of Plant, Soil and Microbial Sciences and Microbiology and Molecular Genetics, have identified an enzyme that dismantles strands of antibiotic-resistant DNA present in wastewater. This process occurs before bacteria can absorb these strands and acquire antibiotic-resistant traits.
According to Hashsham, this method could serve as a robust, environmentally safe means to manage the spread of antibiotic resistance in wastewater, ultimately aiding in the maintenance of antibiotic effectiveness.
The research team at MSU published their results in Nature Water on August 19, alongside faculty members from the University of Science and Technology of China. Hashsham intends to continue trials with the enzyme and examine its potential as a disinfectant for wastewater.
“As with any new discovery, there is more work to be done to optimize the technology,” Hashsham noted. “But this represents a genuinely novel approach.”
Antibiotic resistance has been a significant challenge in modern medicine since the introduction of penicillin, primarily due to improper use and overprescribing of medications. Bacteria continually adapt in response to new antibiotics entering the market. On average, each new antibiotic remains effective for just five to eight years before bacteria evolve, complicating the treatment of infections, Hashsham explained. This innovative technology may aid in preserving the effectiveness of existing antibiotics.
While medical professionals are now more thoughtful about antibiotic prescriptions, researchers are also working to curb the spread of antibiotic-resistant microbes. Wastewater treatment facilities serve as a critical area for these resistant microbes since patients expel the bacteria through their bodily waste.
Additionally, wastewater contains mobile genetic elements that carry antibiotic resistance genes. When these elements are taken up by harmful bacteria, the bacteria thus acquire antibiotic resistance.
The researchers proposed using a restriction enzyme, which functions like a pair of scissors to chop genetic material into fragments that no longer have any utility. Although these enzymes are well-established in molecular biology, they haven’t previously been applied to antibiotic resistance.
To produce an enzyme known as a nuclease, referred to as a “DNA scavenger,” the researchers cultivated the bacteria Shewanella oneidensis. This treatment is projected to be cost-effective for wastewater facilities without adversely affecting the other chemicals used for disinfection.
When the enzyme was added to wastewater in concentrated amounts, it acted as a DNA cleanup crew. Almost all four types of mobile genetic elements were eliminated within four hours, and complete inactivation occurred within six hours.
“Further research is necessary with larger systems and more diverse wastewater compositions to refine this discovery, align it with existing disinfection methods, and ensure cost-effectiveness,” Hashsham remarked.
The next phase involves testing the effectiveness of the DNA scavenger on additional mobile genetic elements. Some researchers speculate that this enzyme may serve as an alternative to chlorine or other disinfectants used in wastewater. While Hashsham is not yet prepared to endorse this idea, he is optimistic that this technique could be a valuable asset in the battle against antibiotic resistance.
