Pseudomonas aeruginosa biofilms found in the lungs of patients afflicted with cystic fibrosis (CF) are extremely resistant to antibiotic treatment. RND efflux pumps were investigated due to their implications in planktonic P. aeruginosa antibiotic resistance. Experiments done exposing biofilms of various single null efflux pump mutants to several different classes of antibiotics failed to establish a correlation between efflux pump expression and antibiotic resistance in biofilms. Bacteria containing mexA-gfp and mexC-gfp
transcriptional fusions were cultivated in biofilms in the presence of carbenicillin. Even though β-lactam antibiotics are known substrates for both the MexAB-OprM and…
