MIXING viruses may result in a treatment for bacterial infections.

Device-related diseases are acquired when a biofilm, a slimy aggregate of bacteria, contaminates medical devices, just like how one can be infected by Urinary Tract Infection (UTI) through unhygienic catheters inserted to the body.

“Instead of making them better, medical devices might even worsen the situation of patients,” said Paola Bianca Buiser, a graduate researcher from the Research Center for the Natural and Applied Sciences.

She warned that these devices might cause several infections, an emerging problem in healthcare facilities.

Traditional treatment for biofilm infections is done through antibiotic therapy, but antibiotic-resistant bacteria or “superbugs” make these drugs ineffective.

Because of this, experts now focus on an alternative method to control and prevent biofilm infections through bacteriophage therapy.

In her study titled “In Vitro Phage Cocktail Therapy against Uropathogenic Escherichia coli and Pseudomonas aeruginosa Biofilms,” Buiser formulated a bacteriophage cocktail—a mixture of phages used to kill disease-causing microorganisms.

Bacteriophages, or simply phages, are viruses that infect a specific host bacterium thereby multiplying inside the cell, causing the bacterial cell to eventually break and release the replicated phages that will infect other bacteria.

“In vitro phage cocktail therapy is basically the use of bacterial viruses or phages in cocktail or mixture as an antibacterial agent against the target pathogen,” Buiser said. “This is done in artificial media and environment in the laboratory where every parameter to be studied is controlled.”

In this method, phages are administered to the contaminated site to kill disease-causing bacteria.

Buiser’s research focused on uropathogenic bacterial biofilms, or bacteria that cause UTI, the most common device-related infection. She said researches on the field are not getting much notice.

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“Since the discovery of antibiotics, phage therapy hasn’t been getting much attention,” she said. “Researchers, nowadays, are more interested with molecular research.”

Testing the cocktails

From 10 sewage treatment plants in Metro Manila, Buiser isolated and identified E. coli and P. aeruginosa hosts.

Six phages belonging to the family Caudovirales were then isolated and purified to acquire the best type of phage that would effectively infect the different strains of the bacterial hosts.

The efficiency of the phages was challenged through a microtiter plate-based assay, a biochemical test to monitor the activity of bacteria infected with phages.

This was done by cultivating the bacterial hosts in an artificial environment having the common elements of urine which will allow biofilm formation in the plates.

Based on Buiser’s experiment, phage-infected biofilm showed lower activity compared to the untreated ones, as there was “lower absorbance with the infected, meaning [the phages] were able to lyse (break) the cells.”

Seeing promising results from her experiment, she started to make a bacteriophage cocktail composed of a mixture of three different phages that could penetrate E. coli and three other phages that could specifically kill P. aeruginosa.

“The two preparations of phage cocktails are composed of three E. coli lytic phages and three P. aeruginosa lytic phages,” Buiser said.

“Both preparations are monophage cocktails, which are composed of three phages of the same species but with different host range and lysis efficiency.”

Her cocktail mix showed similar results as her individual phage tests, indicating the cocktail’s potential as an effective alternative to eliminate biofilms.

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“These cocktail phages have effectively penetrated the thick structure of biofilms that enabled them to infect the embedded target bacterial cell with high lysis efficiency and effectivity,” Buiser said.

She said that it could be used to remove biofilms in medical devices, as well as the possibility of limiting the development of antibiotic resistance among different bacteria.

Buiser plans to study further on the mechanism of phages and their interactions with biofilms, as well as the efficiency of lytic phages.

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