Impact of N-Acetylcysteine and Antibiotics Against Single and Dual Species Biofilms of Pseudomonas aeruginosa and Achromobacter xylosoxidans.

Lungs of cystic fibrosis patients are often colonized or infected with organisms, such as Pseudomonas aeruginosa and other emerging pathogenic bacteria such as Achromobacter xylosoxidans. Further, it is well established that infections of the cystic fibrosis lung airways are caused by polymicrobial infections, although its composition and diversity may change throughout the patient's life. In the present study, we investigated the effects of N-acetylcysteine (NAC) and amikacin, aztreonam, ciprofloxacin, and tobramycin alone and in combination against single- and dual-species biofilms of P. aeruginosa and A. xylosoxidans, in vitro and in the Caenorhabditis elegans infection model. Results showed that tobramycin and ciprofloxacin were the most effective antibiotics, while aztreonam was the least effective antibiotic against both single- and dual-species biofilms of P. aeruginosa and A. xylosoxidans. However, NAC showed little effect on both single- and dual-species, even with a combination of antibiotics. Increased survival was observed in C. elegans when treated with NAC in combination with tobramycin or ciprofloxacin, compared to no treatment or NAC alone. Tobramycin and ciprofloxacin were found effective in biofilms, but more research is needed to better understand the effects of NAC and antibiotics against single- and dual-species biofilms.