Phage therapy used to cure prosthetic valve infection

Heart failure

By Michael Woodhead

16 Jul 2019

Bacteriophage therapy has been used for the first time in Australia as an adjunct to antibiotic treatment for prosthetic valve endocarditis.

Clinicians at Westmead Hospital in Sydney have reported the successful use of a commercial bacteriophage product in the case of a 65-year-old man with a 30-year-old mechanical aortic valve and severe staphylococcal infection.

The man had a previous episode of valve endocarditis 8 years earlier, which had been treated with antibiotics alone.

When he presented again with fever, malaise and other symptoms suggestive of endocarditis, he was found to have methicillin-sensitive S. aureus on blood cultures. Atransoesophageal echocardiography confirmed vegetations on prosthetic aortic and native mitral valves, and a possible aortic root abscess.

In conjunction with infectious disease clinicians and researchers of the Westmead Institute’s Bacteriophage Therapy Team, the man was started on a novel bacteriophage treatment, AB-SA01. The phage treatment developed by US-based AmpliPhi Biosciences is a highly purified preparation of three obligately lytic Myoviridae.

Phage therapy was given intravenously twice daily for 14 days, in conjunction with high dose intravenous flucloxacillin, ciprofloxacin and rifampicin.

The patient showed progressive reductions in C-reactive protein, temperature, and white cell count  within 24 hours.  His symptoms including fevers, tachycardia, hypotension resolved within days of starting bacteriophage infusions and he recovered to return home after 40 days.

There were no adverse effects attributable to the phage therapy, and the man showed no cardiac lesions on PET scan at 80 days.

However he later developed progressive heart failure with a severely dilated left ventricle with moderate mitral and trivial aortic regurgitation, and died after 103 days.

Nevertheleless, the team said the results showed the potential for adjunctive bacteriophage therapy in the treatment of staphylococcal prosthetic valve endocarditis,  especially when surgical intervention is not feasible.

The Westmead team recently reported successful use of phage therapy in 13 critically ill patients with life-threatening Staph aureus infections not responding to antibiotic therapy, of whom seven had endocarditis.

“Future controlled trials are needed to evaluate adjunctive bacteriophage therapy,” they suggested.

The findings are published in the MJA.

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