Nanoconcentrations of 1,9-dimethylmethylene blue (DMMB) associated to Laser, LED or Polarized light are highly effective on AmPDT carried out in aerobes and aerotolerant anaerobes Grampositive bacteria

摘要

Antimicrobial Photodynamic Therapy (AmPDT) is an alternative to conventional treatments of local infections such as theuse of antibiotics, which may lead to the development of resistance. AmPDT in addition of requiring the use of aphotosensitizer it also needs a light source executed. In search of an efficient and cheap procedure, we aimed to assess theefficacy of using 1,9-dimethylmethylene blue (DMMB) as photosensitizer associated with the use of either Laser (λ660nm), LED (λ632 ± 2 nm) or a multispectral polarized light (λ400 – 2000 nm) using different energy densities to kill E.faecalis (Laser or LED) or S. aureus (PL) in vitro. For this, 300 (S. aureus) or 3.32 ηg/ml (E. faecalis) of DMBB andenergy densities of 5 (PL) or 18 J/cm~2 (Laser/LED) were used. Five minutes of pre-incubation time was used. CFU count(S. aureus) or the most probable number method (MPN) (E. faecalis) were used as assessment methods. The results showeda 99.97 % reduction on CFU counts of S. aureus and 99.999998 % reduction on E. faecalis (using both light sources). It isconcluded that AmPDT carried out with 1,9-dimethylmethylene blue associated with either Laser, LED or Polarized lightwas efficacious on the reduction, in vitro, of the counts of aerobes and aerotolerant anaerobes Gram-positive bacteria.