Abstract
Aim
To evaluate antimicrobial activity of Sb-1 and Pyo-bacteriophage in preventing and eradicating MRSA biofilm in vitro using isothermal micro calorimetry.
Method
Two S. aureus specific bacteriophages, Sb-1 and Pyo-bacteriophage cocktail, were tested against S. aureus MRSA (ATCC 43300). MRSA biofilm was formed on porous glass beads and incubated for 24 h at 37° C in BHI, washed 3 times and exposed to different concentrations of bacteriophages. For biofilm prevention, MRSA (5×106 CFUs/ml) was incubated with different phage titers. Glass beads were placed in the calorimeter and heat flow (µW) and total heat (J) were measured in real-time for 48h (eradication) or 24h (prevention).
Results
Both tested bacteriophages rapidly inhibited the heat production of MRSA biofilm in a concentration-dependent manner during the first 24h, as shown for Sb-1 in Figure 1 A. After 48 h-expositions all the titers of bacteriophages show a strong reduction of biofilm viability (Figure 1B). MRSA biofilm was eradicated only by co-incubation with the highest Sb-1 phage titer (107 PFUs/ml) (Figure 1A-B). In prevention experiments, significant reduction of MRSA heat production was already achieved at a lower titer (102 PFUs/ml) of both Sb-1 and Pyo-bacteriophage and in the presence of 104 PFUs/ml the heat production was completely abolished.
Conclusions
Sb-1 and Pyo-bacteriophage are promising phages for treatment MRSA biofilms, as well as for preventing device colonization and controlling biofilms on surface. Their potential activity combined with antibiotics should be further investigated.
