Bactericidal Viruses May Prevent Medical Device Infections

A new study describes how bacteriophages can be enlisted to combat Proteus mirabilis, a bacterium that commonly encrusts and blocks urinary catheters.

Researchers at the University of Brighton (United Kingdom), Queen Victoria Hospital (QVH; East Grinstead, United Kingdom), and other institutions made in vitro models of the catheterized urinary tract, thus simulating a complete closed drainage system as used in clinical practice. The models were then used to mimic either an established infection or early colonization of the catheterized urinary tract, and to examine the outcomes of a single dose of a 3-phage cocktail.

The researchers then measured the impact of the phage cocktail on the time taken for the catheters to block, as well as on levels of crystalline biofilm formation. The results showed that in models of established infection, phage treatment increased the time taken for catheters to block three-fold, when compared to untreated controls. However, in models that simulated early-stage infection, the 3-phage treatment eradicated P. mirabilis and prevented blockage entirely.

A further analysis of catheters from models of established infection 10 hours after phage application demonstrated significantly reduced crystalline biofilm formation, but did not significantly reduce the level of planktonic cells in residual bladder urine. According to the researchers, the results show that bacteriophages are a promising strategy for the prevention of catheter blockage, but that delivering phages in sufficient numbers and within a key therapeutic window will be crucial for the successful application of the method. The study was published in the March 2016 issue of Antimicrobial Agents and Chemotherapy.

“Our work provides good initial evidence that bacteriophage can treat infections caused by Proteus mirabilis, and prevent catheter blockage,” said lead author Brian Jones, PhD, head of research and development at QVH. “This could lead to new ways of managing patients fitted with urinary catheters, providing much benefit to a large number of patients, and also contribute to reducing antibiotic use and tackling resistance.”

“We are still at a very early stage in this work, and have a long way to go before we can be sure this will lead to an effective way to control these infections, but bacteriophage have been used extensively in other countries for decades, and the challenge of antibiotic resistance makes it important to look at using these promising alternatives to antibiotics,” concluded Dr. Jones. “We think an important issue will be in developing ways to deliver bacteriophage as needed, which is a key aim of our ongoing work.”

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University of Brighton
Queen Victoria Hospital