Download Combination Treatment for MRSA Nasal Carriage and MRSA-infected Wounds - +++

Knowledge Transfer Centre
Combination Treatment for MRSA Nasal Carriage
and MRSA-infected Wounds
Ranalexin
Lysostaphin
Ranalexin +
Lysostaphin
Treated
catheter
tubing
MRSA
growth
Activity
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Applications
 Topical agent to eradicate MRSA nasal carriage in preoperative patients as an alternative to mupirocin.
 Incorporated into dressings or applied topically to treat
MRSA-infected wounds.
 Anti-Staphylococcal coating for indwelling medical
devices, such as catheters.
 Treatment to specifically remove Staphylococcus aureus
and MRSA from skin or other surfaces.
The Technology Opportunity
Methicillin-resistant Staphylococcus aureus (MRSA) is the most common drug-resistant pathogen that
can infect skin, soft tissues, major organs and the blood. MRSA infections are often resistant to
conventional antibiotics compromising effective treatment meaning new and reliable therapies are
urgently required.
Patients colonised by S. aureus or MRSA are more likely to be infected and so patients, identified as
carriers prior to surgery, are treated to eradicate these pathogens. However, resistance to mupirocin,
the antibiotic of choice for reducing such carriage, is increasing and treatment failure is more often
encountered. Hence a particularly attractive opportunity exists to provide an alternative decolonisation cream.
The Technology
The new treatment is a combination of a peptide (ranalexin) with a bacteria cell wall-digesting protein
(lysostaphin), which specifically targets and kills Staphylococcus aureus, including MRSA. The
combination is synergistic meaning that these components are more active together compared to the
components on their own. Resistance to new antibiotics can arise rapidly but when antibiotics are
used in combination the opportunity for bacterial resistance is greatly reduced provided that, as with
this treatment, the compounds act on different bacterial targets. Importantly the combination is
synergistic against lysostaphin-resistant S. aureus and also vancomycin-intermediate resistant (VISA)
isolates. Furthermore, unlike conventional antibiotics the combination kills non-multiplying bacteria.
The combination is highly efficacious in vivo in a rabbit model, ex vivo on the surface of human skin
and when dried on the surface of catheter tubing. In a rabbit model, we demonstrated that when the
combination is impregnated into dressings and applied to MRSA-infected wounds for 5 days it
reduces MRSA in these lesions by >99% compared to the untreated controls and wounds treated with
the individual components alone. Moreover, the combination was more effective compared to
vancomycin-treated animals. Thus, the combination can be used topically to treat MRSA-infected
wounds.
Similarly, the combination demonstrated enhanced efficacy for reducing MRSA on living human skin
compared to the individual components alone. Thus, the combination is an effective de-colonisation
agent specifically capable of reducing MRSA carriage without adversely affecting the skin’s normal
protective microflora. Additionally, the combination is active on the surface of catheter tubing and can
reduce the viability of MRSA biofilms meaning it has application as a coating for indwelling medical
devices.
IPR Status
The University of St. Andrews has applied for International (PCT) patent protection (No.
PCT/GB2007/001157) and US patent protection (No. 12/225441).
The University would welcome enquiries from commercial parties interested in entering into a
licensing arrangement and/or collaboration to further develop this technology.
If you would like to explore this opportunity in more detail please contact:
Dr Ewan Chirnside
Knowledge Transfer Centre
The Gateway
University of St Andrews
St Andrews, Fife, KY16 9SS, UK
T: + 44 (0) 1334 462163
F: +44 (0) 1334 462386
E-mail: [email protected]
Additional information can be made available under a Confidentiality Agreement.