Thermally triggered release of the bacteriophage endolysin CHAPK and the bacteriocin lysostaphin for the control of methicillin resistant Staphylococcus aureus (MRSA)

Abstract

Staphylococcus aureus infections of the skin and soft tissue pose a major concern to public health, largely owing to the steadily increasing prevalence of drug resistant isolates. As an alternative mode of treatment both bacteriophage endolysins and bacteriocins have been shown to possess antimicrobial efficacy against multiple species of bacteria including otherwise drug resistant strains. Despite this, the administration and exposure of such antimicrobials should be restricted until required in order to discourage the continued evolution of bacterial resistance, whilst maintaining the activity and stability of such proteinaceous structures. Utilising the increase in skin temperature during infection, the truncated bacteriophage endolysin CHAPK and the staphylococcal bacteriocin lysostaphin have been co-administered in a thermally triggered manner from Poly(N-isopropylacrylamide) (PNIPAM) nanoparticles. The thermoresponsive nature of the PNIPAM polymer has been employed in order to achieve the controlled expulsion of a synergistic enzybiotic cocktail consisting of CHAPK and lysostaphin. The point at which this occurs is modifiable, in this case corresponding to the threshold temperature associated with an infected wound. Consequently, bacterial lysis was observed at 37 °C, whilst growth was maintained at the uninfected skin temperature of 32 °C.

Recombinant Endolysins as Potential Therapeutics against Antibiotic-Resistant Staphylococcus aureus: Current Status of Research and Novel Delivery Strategies

“…While no bacterial lysis in the presence of the NPs occurred at 32°C (the temperature of healthy skin), numbers of S. aureus bacteria were reduced by Ͼ4 log units when the temperature was increased to 37°C, owing to the release of the active enzyme mix. CHAP K and lysostaphin were chosen for these experiments due to their demonstrated synergistic effect when used in combination (199).…”

Synergistic Inhibition by Bacteriocin and Bacteriophage against Staphylococcus aureus

“…In the study, the combination of nisin and EDTA showed a synergistic effect but the combination of nisin and bacteriophage did not. Hathaway et al (2017) designed a nanoparticle harboring a bacteriophage endolysin and a bacteriocin for controlling methicillin-resistant S. aureus (MRSA) on human skin that could release the included molecules by temperature control. The nanoparticles worked effectively at 37℃, the temperature associated with skin wounded by infection, and cell lysis was observed.…”

Prevention of encrustation and blockage of urinary catheters by Proteus mirabilis via pH-triggered release of bacteriophage

“…Additionally, recent advances in therapy using bacteriophage products, namely bacteriophage-encoded endolysins, which are utilised in end stages of phage infection, and care capable of enzymatically degrading the bacterial cell wall through digestion of the peptidoglycan polymeric material, resulting in cell death by osmolysis. 38 Endolysins have been use synergistically with antibiotics to give increased antibiotic activity against otherwise resistant Gram-negative strains. 53 Other factors potentially hindering phage efficacy include the inhibition of phage adhesion to their bacterial hosts owing to the accumulation of struvite and apatite crystalline precipitates, or the physiological state of the cells themselves, since log-phase cells are lysed more efficiently than those in a state of partial or full metabolic quiescence (such as those within a biofilm).…”

“…33,34 Recently, emphasis has been placed on developing methods of active, or triggered release of antimicrobial agents in response to external stimuli (e.g. pH, [35][36][37] temperature, 38,39 or biomarker signals 40 ), in order to achieve a 'burst response' of the active cargo. Triggered release formulations can be used to reduce the amount of drug necessary to cause the same therapeutic effect in patients, as well as ensuring that the cargo is released only in the physiological location required, thus reducing systemic dosage and its associated complications.…”