Bloodstream infections are potentially life-threatening diseases. They can cause serious secondary infections, and may
result in endocarditis, severe sepsis or toxic-shock syndrome. Pseudomonas aeruginosa is an opportunistic pathogen and
one of the most important etiological factors responsible for nosocomial infections, mainly in immuno-compromissed
hosts, characteristic of patients with severe burns. Its multiresistance to antibiotics produces many therapeutic problems,
and for this reason, the development of an alternative method to antibiotic therapy is needed. Photodynamic inactivation
(PDI) may be an effective and alternative therapeutic option to prevent bloodstream infections in patients with severe
burns. In this study we report the use of PDI to prevent bloodstream infections in mice with third-degree burns. Burns
were produced on the back of the animals and they were infected with 109 cfu/mL of multi-resistant (MR) P. aeruginosa.
Fifteen animals were divided into 3 groups: control, PDT blue and PDT red. PDT was performed thirty minutes after
bacterial inoculation using 10μM HB:La+3 and a light-emitting diode (LED) emitting at λ=460nm±20nm and a LED
emitting at λ=645 nm±10nm for 120s. Blood of mice were colected at 7h, 10h, 15h, 18h and 22h pos-infection (p.i.) for
bacterial counting. Control group presented 1×104 cfu/mL in bloodstream at 7h p.i. increasing to 1×106 at 22h, while
mice PDT-treated did not present any bacteria at 7h; only at 22h p.i. they presented 1×104cfu/mL. These results suggest
that HB:La+3 associated to blue LED or red LED is effective to delay and diminish MR P.aeruginosa bloodstream
invasion in third-degree-burned mice.