Enzyme found to tackle MRSA

Micreos, a Dutch biotech company, has developed Staphefekt, a bacteria-killing enzyme specific to staphylococcus aureus, which it claims is equally effective in killing methicillin-resistant staphylococcus aureus (MRSA) as methicillin-susceptible staphylococcus aureus (MSSA).

Staphefekt is claimed to be the first endolysin available for human use on intact skin.

The working mechanism of endolysins is unrelated to that of antibiotics, meaning even bacteria resistant to antibiotics are susceptible.

Staphefekt exhibits several other characteristics: rapid killing (lysis) of the target bacteria and very limited likelihood of emerging resistance, as it works independently of the bacterial metabolism - which harbours the resistance mechanisms - and targets a region of the bacterial cell wall less susceptible to mutation. An additional feature is that its action is specific to S. aureus and does not affect beneficial bacteria.

Dr Bjorn Herpers, Clinical Microbiologist, MD, PhD at Public Health Lab, Kennemerland, speaking at Antibiotics alternatives for the new millennium in London said:

“The results are exciting, and demonstrate the potential this technology has to revolutionise the way we treat certain bacterial infections. With the increasing prevalence of multidrug-resistant bacteria, new strategies for the treatment of bacterial infections are needed. As well as being less prone to resistance induction than antibiotics, endolysins destroy only their target bacterial species, leaving the beneficial bacteria alone.”

In vitro and observational in vivo studies, presented in London, have confirmed these characteristics. Laboratory results have shown that lysis of S. aureus by Staphefekt is specific to S. aureus, efficient, and unlikely to induce resistance.

Observational patient case series have demonstrated similar efficacy. In one case series, after the local application of Staphefekt for one week, S. aureus was eradicated from the lesions of S. aureus-positive rosacea patients, while other commensal skin inhabitants (such as S. epidermis) remained present.  In another case series, S. aureus was found in six skin cultures before treatment (three patients with constitutional eczema, two with contact dermatitis and one with peri-oral dermatitis). In five of six patients, symptoms diminished during treatment with Staphefekt, and patients reported less or no need for corticosteroids.

Mark Offerhaus, Micreos CEO added: “With the introduction of Staphefekt, we enter a new era in the fight against antibiotic resistant bacteria, targeting only the unwanted bacteria. This is a far more logical and elegant approach. Millions of people stand to benefit. That’s very exciting and gratifying.”

Micreos has started clinical trials for new therapeutic areas, and is looking to collaborate with clinicians internationally to establish further trials.