As bacteria develop resistance to an increasing number of antibiotics, doctors have been searching for a way to counter antibiotic resistance and increase the power of antimicrobial agents. This is a complicated problem, however. As a last resort, researchers have turned to bacteria-munching viruses called bacteriophages. On the other hand, new antibiotics appear to be far in the future. Could cranberry compounds hold a key against resistance?
Cranberry Compounds Block Bacteria from Evolving Resistance:
Researchers in Montreal, Canada, were excited to discover that compounds from cranberries can block common bacteria from developing antibiotic resistance (Advanced Science, May 28, 2019). The proanthocyanidins that give cranberries their deep red color disrupt biofilm formation and prevent the evolution of resistance to tetracycline and several other antibiotics.
By themselves, cranberry proanthocyanidins had no effect on the growth of the bacteria. However, these cranberry compounds potentiated the effectiveness of several commonly used antibiotics. Examples include sulfamethoxazole and azithromycin.
Two Bacterial Pathways Inhibited:
The research shows that the compounds affect two different pathways bacteria use to develop antibiotic resistance. First, the compounds help antibiotics penetrate the bacterial cell membranes. In addition, they shut down the pumps bacteria use to move toxins like antibiotics out. Importantly, researchers tested the compounds not only in test tubes and petri dishes, but also in living creatures. They infected two different types of insects and treated them with cranberry compounds alone or in combination with antibiotics. The combination treatments increased insect survival rates.
According to the scientists,
“The ability to potentiate the action of antibiotics in a patient could improve treatment outcomes and hinder the emergence of antibiotic‐resistant infections.”