Acetic acid effective against bacteria in burn wounds

Photo: Colorful letters spell "acetic acid"

Highly diluted acetic acid shows antibacterial activity when topically applied to burn wounds; © tutul_1410

Highly diluted acetic acid, an active ingredient of household vinegar, has been shown to be an effective alternative agent to prevent infection and kill bacteria found in burn wounds.

Researchers from the University of Birmingham and the National Institute for Health Research (NIHR) Surgical Reconstruction and Microbiology Research Centre (SRMRC) investigated the antibacterial activity of acetic acid against key burn wound colonizing organisms growing both planktonically and as biofilms.

Burns are a common traumatic injury and prone to becoming infected due to loss of a normal skin barrier. Local infection of the burn wound and subsequent sepsis (blood poisoning) are key concerns for patients, with sepsis the leading cause of death among patients with burn wounds. Infections of burn wounds are difficult to treat with traditional antibiotics as they do not effectively reach the wound, and the infecting organisms are often highly antibiotic resistant.

The study, published in PLOS ONE, demonstrated that low concentrations of acetic acid can be used to treat biofilms, and therefore could be used as alternatives to topical (surface applied) antimicrobials and traditional antimicrobial dressings for preventing bacterial colonization of burns. The current use of acetic acid in clinical settings has been limited due to concerns of patient tolerability. The finding that it is effective at far lower concentrations than previously thought, therefore offers hope for the development of novel treatments.

Fenella Halstead, NIHR SRMRC Clinical Scientist at the Queen Elizabeth Hospital, explained: "As resistance to antibiotics grows, we need to find ways to replace them with alternative topical agents that can kill bacteria and help our burns patients. The evidence in this study offers great promise to be a cheap and effective measure to do just that."

29 isolates of common wound-infecting pathogens including Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp. were grown in the laboratory.

The ability of highly diluted acetic acid to inhibit growth of pathogens, prevent the formation of biofilms, and then eradicate pre-formed biofilms was tested on each isolate. Low concentrations of acetic acid (0.16-0.3 percent) were shown to be able to inhibit growth of all strains, prevent them from forming biofilms (bacteria attached to a surface) and also to eradicate mature biofilms for all isolates after three hours of exposure.

Previous clinical use of acetic acid as an antimicrobial treatment has used much higher concentrations of 2.5 percent. Halstead continued: "A key way in which bacteria cause infection is in a biofilm; where instead of living as single cells they form a community in the form of a slimy layer that we see on a wound, on a valve or on a catheter, for instance. As much as 80 percent of infections in the body are due to these biofilms which, typically, are even more resistant to antibiotics because they essentially have safety in numbers and their metabolic rate is a lot slower. For that reason, seeing that acetic acid was effective against all types of these pathogens was really great."

The team is now designing clinical trials with acetic acid in which they will test plain dressings soaked with acetic acid, against the more commonly used silver-based dressings. A further study will test the effectiveness of two specific concentrations of acetic acid on patients at the Healing Foundation Centre for Burns Research based at the Queen Elizabeth Hospital.; Source: University of Birmingham

Read more news from the University of Birmingham at: