An observational prospective study of topical acidified nitrite for killing methicillin-resistant Staphylococcus aureus (MRSA) in contaminated wounds.
BACKGROUND
Endogenous nitric oxide (NO) kills bacteria and other organisms as part of the innate immune response. When nitrite is exposed to low pH, NO is generated and has been used as an NO delivery system to treat skin infections. We demonstrated eradication of MRSA carriage from wounds using a topical formulation of citric acid (4.5%) and sodium nitrite (3%) creams co-applied for 5 days to 15 wounds in an observational prospective pilot study of 8 patients.


RESULTS
Following treatment with topical citric acid and sodium nitrite, 9 of 15 wounds (60%) and 3 of 8 patients (37%) were cleared of infection. MRSA isolates from these patients were all sensitive to acidified nitrite in vitro compared to methicillin-sensitive S. aureus and a reference strain of MRSA.


CONCLUSIONS
Nitric oxide and acidified nitrite offer a novel therapy for control of MRSA in wounds. Wounds that were not cleared of infection may have been re-contaminated or the bioavailability of acidified nitrite impaired by local factors in the tissue.
Division of Applied Medicine, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen, AB24 2ZD, UK. a.d.ormerod@abdn.ac.uk.
Anthony D
AD
Ormerod
Amjad Aj
AA
Shah
Hong
H
Li
Nigel B
NB
Benjamin
Gail P
GP
Ferguson
Carlo
C
Leifert