L. rhamnosus extracts inhibit pyocyanin production in P. aeruginosa through expression of phzB

Pseudomonas aeruginosa is a gram-negative rod-shaped bacterium which can cause several serious infections such as septicemia, pneumonia or UTIs. They are one of the most common nosocomial infections, affecting those with cancer, cystic fibrosis, HIV, and others that are immunocompromised. P. aeruginosa employs a variety of virulence factors including exotoxin A, proteases, and pyocyanin. Pyocyanin can damage DNA, cause neutrophil apoptosis, and produce harmful reactive oxygen species. A bacterium found in the intestines which helps gut and immune health called Lactobacillus rhamnosus has antimicrobial properties. This study examined the effects of L. rhamnosus extracts on pyocyanin production in P. aeruginosa. In the presence of L. rhamnosus extracts, there was a decrease in pyocyanin production. In addition, the effects of these extracts on phzB expression were determined using RT-PCR. There was a 40% decrease in phzB expression when cells were grown with L. rhamnosus extracts. Utilizing the antimicrobial properties of a natural, friendly bacterium like L. rhamnosus could be helpful by regulating the phzB gene in P. aeruginosa that is involved in pyocyanin production.