Saturday, February 25, 2017

Prevention and treatment of propionibacterium biofilms

Prevention of Propionibacterium acnes biofilm formation in prosthetic infections in vitro

These authors studied biofilm formation on synthetic calcium sulfate (CaSO4) bone void filler beads using scanning electron microscopy (SEM) over a period of 14 days.

Here are some SEM photographs of Propionibacterium biofilm formation on the surface of an unloaded pharmaceutical-grade calcium sulfate alpha-hemihydrate bead over a period of 14 days. Surface colonization was observed at day 3 with evidence of extracellular polymeric substance (EPS) strands  (indicated by arrows), with small microcolonies noted at day 7 with more extensive EPS deposition. At day 14, biofilm was observed across  the bead surface over a matted layer of EPS. Scale bars equal 10 μm.

Beads loaded with vancomycin/tobramycin were able to kill planktonic cultures of 106 colony-forming units/mL, prevent bacterial colonization, and significantly reduce biofilm formation over periods of weeks. 

Here is a graph showing Propionibacterium biofilm formation over a period of 14 days in the presence of antibiotic-loaded pharmaceutical-grade calcium sulfate alpha-hemihydrate (PG-CSH) beads as determined by confocal laser scanning microscopy images and colony-forming unit (CFU) counts (CFUs per square centimeter). Data represent the mean of 3 experimental repeats (15 data points, n = 5 per experimental repeat) with standard deviation bars. Arrows indicate a fresh bacterial challenge of 106 CFU/mL every 72 hours. Scale bars equal 25 μm.

Comment: This is an interesting study showing the effectiveness of local antibiotic elution from calcium sulfate beads in preventing and treating Propionibacterium biofilms in vitro. Future in vivo models and clinical experience will help define the role of this approach for prophylaxis in high risk patients and in treatment for patients suspected of having Propionibacterium infections.