LED 209 conjugated chitosan as a selective antimicrobial and potential anti-adhesion material

The rapid emergence of antibiotic-resistant Gram-negative bacteria (GNB) is becoming a global healthcare concern, and it urgently needs novel strategies to match the clinical challenge. In this work, we conjugated chitosan (CS) with LED 209, a highly selective inhibitor of QseC of GNB, to create the novel selective antimicrobial agent CS/LED. The data of FT-IR, NMR and elemental analysis for CS/LED conjugates proved the successful conjugation of CS with LED 209. Interestingly, the fluorescence signal detected in MDR-E. coli of CS/LED-FITC was about 2 times than that of CS-FITC at 3 h. The results shown that compared with CS, CS/LED exhibited higher selective antimicrobial on MDR-E. coli. Moreover, CS/LED exhibited the lower selectivity and cytotoxicity to mammalian cell than CS. Additionally, an unexpected enhancement of anti-adhesion activity against MDR-E. coli was determined by cellulose membrane coating CS/LED. The results demonstrated that CS/LED could reduce the adhesion of bacteria to the cellulose membrane by about 67.8%, while CS only reduced by about 45.3%. The dressings coated with CS/LED possessed the stronger ability to prevent microbial adhesion compared to the CS-coated dressing. Our present work firstly demonstrated that CS/LED had a highly selective activity and anti-adhesion activity against MDR-E. coli, which offered a potent and selective antimicrobial for combating multidrug-resistant GNB infections.