It has been suggested that theV8 protease plays an important role

It has been suggested that theV8 protease plays an important role in the pathogenesis of S. aureus, as strains lacking this enzyme show Selonsertib reduced virulence in a number of infection models [17–19]. Of particular relevance is a murine abscess model, in which inactivation of V8 protease resulted in significant attenuation of virulence [18]; therefore inactivation of this enzyme by PDT may be able to reduce the virulence potential

of S. aureus Vactosertib clinical trial in other hosts. As staphylococcal proteases and the colonisation of atopic skin by S. aureus have been implicated in the pathogenicity of atopic dermatitis [20], the inactivation of proteolytic enzymes could have particular relevance for the decontamination of infected lesions using PDT. PDT using the combination of methylene blue and laser light of 665 nm may therefore be of use in the treatment of atopic skin disorders. In fact, PDT has long been shown to be beneficial in the treatment of atopic skin disorders,

for example the use of ultraviolet light and 8-methoxypsoralen for the treatment of atopic dermatitis [21]. Clearly, the combination of elimination of disease-exacerbating microorganisms and neutralisation of virulence factors would be extremely advantageous to the treatment of these diseases. The treatment of α-haemolysin with methylene blue and laser light resulted in an effective inhibition of haemolytic activity. Concentrations of methylene blue ranging from 1-20 μM all had an inhibitory effect on α-haemolysin www.selleckchem.com/products/pha-848125.html when irradiated with laser light, and α-haemolysin was shown to be inactivated after an irradiation time of just 1 minute (1.93 J/cm2)

when in the presence of 20 μM methylene blue. The results shown here demonstrate that α-haemolysin is the most susceptible of the virulence factors tested, perhaps due to the nature of its amino acid composition, which may leave it more vulnerable to attack Selleck Rapamycin by reactive oxygen species. These data indicate that photodynamic inactivation of this toxin is highly effective and as such, could significantly attenuate the virulence of S. aureus due to the multiple functions of α-haemolysin as a virulence factor. The haemolysins of S. aureus are membrane-damaging toxins that are capable of lysing a number of different cell types. α-haemolysin is thought to be important in infection as it has a number of detrimental effects on host cells due to the disruption of ion transport across host cell membranes, ultimately leading to apoptotic cell death and oedema [10]. α-haemolysin can cause cell death in different ways depending on the concentration of the toxin. At high concentrations, α-haemolysin forms large pores in lipid bilayers that result in massive necrosis, whilst low doses result in the formation of small pores that result in apoptosis and DNA fragmentation [22].

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