We had earlier reported about a team of researchers led by Terri Camesano discovering cranberry juice to probably help fight bacteria at a molecular level. Well, now the scientists at Worcester Polytechnic Institute (WPI) have noticed that the cranberry juice cocktail can block a strain of Staphylococcus aureus (S. aureus) for infecting other cells in a clinical study. Initially they studied the dangerous form of E. coli, which was a main cause of most urinary tract infections.
On the other hand strains of S. aureus are seemingly capable of causing staph infections that can range from trivial skin rashes to severe bloodstream infections. Especially one particular strain known as Methicillin-resistant Staphylococcus aureus or MRSA is said to create several public health issues at medical institutions since it does not respond to most antibiotics.
“Most of our work with cranberry juice has been with E. coli and urinary tract infections, but we included Staphylococcus aureus in this study because it is a very serious health threat,” Camesano stated. “This is early data, but the results are surprising.”
In order to cause an infection bacteria have to initially stick to a host and then they form colonies, subsequently after which they create a biofilm. Researchers in this study enlisted female students who were healthy from WPI. They were then asked to drink cranberry juice or placebo fluid, which is similar to the juice in terms of its looks and taste. After which the subjects were asked to provide their urine samples at prescribed intervals once they had drank the fluid or juice given to them.
Subsequently, those samples had been incubated in petri dishes along with numerous strains of E. coli and a single strain of S. aureus. Camesano’s team then used a special dye to stain the bacteria. With the help of a spectrophotometer they measured the density of the bacterial colonies growing in the dishes over a period of time. On analyzing the samples they found that the ability of the E. coli and the S. aureus to from biofilms of the surface of the dishes was reduced by those who had drank the cranberry juice cocktail. There was a significant reduction in the ability of the bacteria present in those samples as compared to the placebo fluid ones.
“What was surprising is that Staphylococcus aureus showed the most significant results in this study,” Camesano stated. “We saw essentially no biofilm in the staph samples, which is very surprising because Staph aureus is usually very good at forming biofilms. That’s what makes it such a health problem.”
The fimbrae present on the E. coli was curled due to the cranberry juice however S. aureous does not have any fimbriae to be curled up. Thus, Camaseno was unable to comprehend how it stops the biofilm formation on the S. aureous. Since bacterial adhesion is necessary for the infection to grow, researchers hope to identify the specific mechanisms and forces that assist in the formation of biofilms. This could help in future studies related to finding the cause of potential drug targets for new antibiotics. Moreover, it might be useful for those studies pertaining to engineering the surfaces of invasive medical devices like catheters in order to make them extremely resistant to bacterial adhesion.
The finding had been explained in the poster presentation at the American Chemical Society’s national meeting in Boston on August 23, 2010. It was elucidated by Terri Camesano, a professor of chemical engineering at WPI.