Figure 7.

Pyruvate-depletion induced dispersion of P. aeruginosa biofilms within second-degree porcine burn wounds reduces the bacterial burden and enhances the efficacy of tobramycin in killing biofilm cells. Burn wounds were infected with P. aeruginosa ATCC® 27312™ and left untreated for 24 h. Wounds were subsequently exposed to increasing concentrations of PDH, tobramycin, or silver sulfadiazine. At days 1, 3 and 6 post infections, adherent and non-adherent bacterial cells were removed using flush & scrub, and the number of viable cells (CFU) per wound determined using viability counts. (A) Number of adherent (biofilm) and non-adherent (planktonic) cells present in wounds. (B) Effect of increasing concentrations of PDH on the P. aeruginosa biofilm population present in burn wounds. Efficacy of PDH (100 and 200 mU), tobramycin (100 µg/ml), or co-treatment of PDH and tobramycin on the (C) P. aeruginosa biofilm population and (D) planktonic population present in burn wounds. Log reduction was determined relative to untreated biofilms post 3 and 6 days infection. (E) Number of adherent (biofilm) and non-adherent (planktonic) cells present in wounds post exposure to silver sulfadiazine (SSD) 3 and 6 days post infection. Prior to SSD treatment, infected wounds were left untreated for 24 h post infection. With the exception of data shown in (B), all experiments were done in in triplicate, with each biological replicate being comprised of 3 wounds per treatment group (n = 9). Experiments shown in (B) are representative data obtained using only 3 wounds per treatment group (n = 3). Error bars represent standard deviation. Error bars represent standard deviation. *Significantly different (p < 0.05) from untreated wounds. **Significantly different (p < 0.05) from wounds treated only with PDH or tobramycin.