Cranberries could be a helpful tool in combating antibiotic resistance

Canada: Proanthocyanidin -- A molecule derived from cranberries -- could help combat the growing threat of antibiotic resistance by mitigating the development of resistance and improving treatment outcomes of antibiotics, suggests a recent study. This could make antibiotics more effective and decrease the spread of acquired antibiotic resistance.

Antibiotic resistance is spreading at an alarming rate among pathogenic bacteria in both medicine and agriculture. If it continues to spread at the same rate it can undermine the decades' long progress done in fighting infections. The overuse of antibiotics in agriculture and medicine could make us return to the pre-antibiotic era in which even a minor infection proved deadly. In light of this, controlling the spread of antibiotic resistance becomes crucial.

Cranberries are highly sought after for their tangy taste and the antioxidants they contain. Now, the study published in the journal Advanced Science has provided evidence that this could also help in the fight against bacteria. The study found that pathogenic bacteria, when treated with proanthocyanidin, become more sensitive to lower doses of antibiotics. And also, the bacteria could not develop resistance to antibiotics.

Given the role of drinking cranberry juice in the treatment and prevention of urinary tract infections, Nathalie Tufenkji, Department of Chemical Engineering, McGill University, Quebec, Canada, and colleagues sought to find more about molecular properties of the berries by treating various bacteria with a cranberry extract. The bacteria selected included those involved in urinary tract infections, pneumonia, and gastroenteritis (Proteus mirabilis, Pseudomonas aeruginosa, and Escherichia coli).

"Normally when we treat bacteria with an antibiotic in the lab, the bacteria eventually acquire resistance over time," said Tufenkji. "But when we simultaneously treated the bacteria with an antibiotic and the cranberry extract, no resistance developed. We were very surprised by this, and we see it as an important opportunity."

Analyses showed that the cranberry extract increases bacterial sensitivity to antibiotics by acting in two ways. First, it makes the bacterial cell wall more permeable to the antibiotic, and second, it interferes with the mechanism used by the bacteria to pump out the antibiotic. Consequently, the antibiotic penetrates more easily, and the bacteria have a harder time getting rid of it, which explains why the drug is effective at lower doses.

The researchers demonstrated that that cranberry proanthocyanidin (cPAC) prevents the evolution of resistance to tetracycline in Escherichia coli and Pseudomonas aeruginosa, rescues antibiotic efficacy against antibiotic‐exposed cells, and represses biofilm formation. Biofilms can lead to chronic bacterial infections and are commonly associated with antibiotic treatment failure.

After confirming the activity of the cranberry molecules on bacterial culture, the researchers tested to determine whether the pattern persisted in a preliminary animal model: infected insects. Since the synergistic effect of the extract and the antibiotic was also observed in the insects, further experiments will be conducted to clearly identify the active molecules.

If the results are confirmed in animals, certain classes of antibiotics subject to high levels of resistance could be made useful again by using cranberry extract to boost their potential.

"We are eager to pursue this research further," Tufenkji said. "Our hope is to reduce the doses of antibiotics required in human and veterinary medicine as part of efforts to combat antibiotic resistance."

For detailed study follow the link: https://doi.org/10.1002/advs.201802333