In 2012, a 76-year-old patient in the United States underwent a Dacron graft for an aortic arch aneurysm. Following the surgery, a Pseudomonas aeruginosa infection developed in the mediastinum and vascular graft. Infection of the vascular graft is one of the most serious complications in vascular surgery. To combat the infection, the patient underwent repeated surgical debridements of the chest wall and numerous long-term courses of antibiotic therapy. However, the infection was never eliminated.

P. aeruginosa is one of the most common pathogens causing hospital-acquired infections worldwide. Combating this microorganism is complicated by its multiple antibiotic resistance and its tendency to form biofilms.

In search of new treatments for the infection, doctors used a bacteriophage active against P. aeruginosa . The OMKO1 bacteriophage was originally isolated from water samples from a lake near Yale University (USA). Now, the virus has helped treat the life-threatening infection.

The OMKO1 bacteriophage is unique in that it attaches to a protein on the surface of P. aeruginosa that confers antibiotic resistance on the pathogen—specifically, a membrane pump that "pumps" the antibiotic out of the bacterium before it can be used. To evade the phage, the bacterium must modify this pump protein, but if it does, it will lose its antibiotic resistance. The researchers say they have thus "backed the bacterium into an evolutionary corner." As a result, synergism is observed when phages and antibiotics are used simultaneously.

After receiving FDA approval, in January 2016, doctors administered a suspension of OMKO1 phages and the antibiotic ceftazidime into the patient's chest, followed by a short course of ceftazidime. For the next 18 months (until the article was published), the patient did not receive antibiotics and there was no recurrence of the infection.

The use of bacteriophage OMKO1 contributed to the destruction of P. aeruginosa biofilms and overcoming the pathogen's resistance to antibiotics.

Original article : Benjamin K Chan, Paul E Turner, Samuel Kim, Hamid R Mojibian, et al. (2018) Phage treatment of an aortic graft infected with Pseudomonas aeruginosa // Evolution, Medicine, and Public Health, Volume 2018, Issue 1, 1 January 2018, Pages 60-66. https://doi.org/10.1093/emph/eoy005