Skip to main content
Skip to navigation

Sept. 27, 2012 Volume 34, No. 6

Viruses able to kill certain kinds of disease-causing bacteria, study shows


Combination of viruses and chlorine knocked out the highest percentage of bacteria biofilm

Viruses may have some benefit after all. They may offer a one-two punch to dangerous bacteria.

University of Missouri scientists are finding that certain viruses known as bacteriophages could be used to efficiently sanitize water treatment facilities and might aid in the fight against deadly antibiotic-resistant bacteria. 

In studies, MU scientists used viruses to kill colonies of Pseudomonas aeruginosa, common disease-causing bacteria. The experiment was the first to use bacteriophages in conjunction with chlorine to destroy biofilms, which are layers of bacteria growing on a solid surface, said Zhiqiang Hu, associate professor of civil and environmental engineering in the College of Engineering. A summary of the experiments was published in the latest issue of the journal Biotechnology and Bioengineering.

“The advantage to using viruses is that they can selectively kill harmful bacteria,” Hu said. “Beneficial bacteria, such as those used to break down wastes in water treatment plants, are largely unaffected. Hence, viruses might be used to kill pathogenic bacteria in water filters that would otherwise have to be replaced. They could save taxpayers’ money by reducing the cost of cleaning water,” he said.

Bacteria can be difficult to kill when they form a biofilm, or outer crust. Biofilms can be killed by chlorine, but the inner bacteria are sheltered. Viruses circumvent the problem by spreading through the inner and outer of a bacteria colony. 

Hu noted that the bacteriophages are easier to create than the enzymes used to attack biofilms. The viruses are also better at targeting specific bacterial species.

The greatest success in killing biofilms was by using a combination of bacteriophages and chlorine, researchers found. An initial treatment with viruses followed by chlorine knocked out 97 percent of biofilms within five days of exposure. When used alone, viruses removed 89 percent of biofilms, while chlorine removed only 40 percent.

“The methods we used to kill Pseudomonas aeruginosa could be used against other dangerous bacteria, even those that have developed resistance to antibiotics,” Hu said. “Our work opened the door to a new strategy for combating the dangers and costs of bacterial biofilms.” 

Hu plans to expand his experiments into a pilot study.