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Scientists Develop New Way to Kill Bacteria

Enzyme product causes cell lysis

A bacteria-killing enzyme specific to Staphylococcus aureus has been developed by scientists in the Netherlands. Study data indicate that the product, called Staphefekt, is equally effective at killing methicillin-resistant and methicillin-susceptible S. aureus (MRSA/MSSA).

According to the product’s developer (Micreos), Staphefekt is the first endolysin available for human use on intact skin. Endolysins are enzymes that originate from bacteriophages –– microorganisms that kill only bacteria. In nature, phages use bacteria to replicate, destroying bacterial cell walls with endolysins in the process. The mechanism of action of endolysins is unrelated to that of antibiotics, meaning that bacteria resistant to antibiotic treatment are susceptible, Micreos says.

Staphefekt reportedly causes rapid lysis of target bacteria and has a small likelihood of emerging resistance, as it works independently of bacterial metabolism –– which harbors resistance mechanisms –– and targets a region of the bacterial cell wall that is less susceptible to mutation. An additional feature of the product is that it affects only S. aureus and does not injure beneficial bacteria.

In vitro and observational in vivo data, presented November 5 in London, have confirmed these characteristics, Micreos says.

The efficacy of Staphefekt against S. aureus has also been demonstrated in a series of patient cases. In one case, after the local application of Staphefekt for 1 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, S. aureus was found in six skin cultures (three from patients with constitutional eczema; two from patients with contact dermatitis; and one from a patient with peri-oral dermatitis) before treatment. In five of the six patients, symptoms diminished during treatment with Staphefekt, and the patients reported less or no need for corticosteroids.

A bacteriophage is a bacterial virus that infects and replicates within a bacterium. Every bacterial strain has co-evolved to have phage counterparts, which depend on the host bacterium to survive and proliferate. Phages use the host bacterium to replicate and to produce new phages, which exit the bacterial cell after cell-wall lysis (bursting) to find new bacteria to infect.

Phages produce enzymes that have the ability to target specific components on a bacterium’s cell wall, resulting in lysis of the bacterium and cell death. These enzymes are known as endolysins.

Source: Micreos; November 5, 2014.

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