Biofilm and planktonic lifestyles modulate lipid A structure and inflammatory response in Pseudomonas aeruginosa from people with cystic fibrosis

The National Institutes of Health of the United States stated that over 80% of microbial infections in the body are due to biofilms, many of which are resilient to traditional antimicrobial treatments and need surgery to resolve the chronic infection. Pseudomonas aeruginosa is a Gram-negative pathogen responsible for biofilm-related infection in immunocompromised patients, including those suffering from cystic fibrosis. Here, we attempted to understand the potential relationship between the structure of bacterial surface glycans and the resistance to antibiotics. We focused the attention on lipopolysaccharides (LPS) of clinical Pseudomonas aeruginosa isolates collected from two people with CF at different disease stages: a wild-type (WT) strain sensitive to all tested antibiotics, isolated from a patient with recent infection (< 12 months), and a pan-drug-resistant (PDR) strain from a patient with chronic colonization (4-15 years). These strains were grown in planktonic conditions and as structured biofilm communities and compared with the reference strain PA14. Structural variations in Lipid A across these two strains were evaluated concerning the degree of antibiotic resistance and chronic infection. Finally, we assessed the effects of LPSs and Lipids A on inflammatory pathway activation, through Collagen 1A1, IL-6, and TLR-4 gene expression evaluation.