Aims: Biofilm infections are chronic and difficult to treat. Bacterial community in the biofilm environment tend to be highly tolerant to antibiotic treatment, which surge the need for a potential alternative therapy. Phage therapy, the use of bacteriophage to treat the bacteria is known to have a great potential against bacteria, especially of multi drug resistant bacteria.   

Objective: This study was proposed to determine the effect of phage and antibiotic combination in clearing the biofilm of Staphylococcus aureus in the human plasma model.

Methods and Results: Three clinical Staphylococcus aureus that formed a strong, moderate and low biofilm in the coated human plasma were treated with phage and antibiotic combination. Two Staphylococcal phage vB_Sau_S90 and vB_Sau_S165 that showed broad host range activity were used in combination with 2X and 10X minimum inhibitory concentration of oxacillin antibiotic. Treatment strategies such as pre-phage, simultaneous and post-phage treatments were administered. The biofilm architecture was observed in a fluorescent microscope. This study demonstrated that bacterial biofilm could be reduced effectively with five doses of phage antibiotic combination in the human plasma model. The phage and oxacillin in combination yielded more than 80% biofilm reduction.

Conclusions: Phage antibiotic combination eradicated the biofilm more effectively. The clearance of biofilms that was formed on human plasma shows that the treatment can be equally effective in the human body and can be a better treatment choice in chronic biofilm infections.

Significance and Impact of the study: The biofilm formed on human plasma was strong to the biofilm in bacteriological media. More improvement in phage therapy to eradicate the biofilm can be dealt with by phage antibiotic combination, which aids in effective eradication of biofilm to phage-alone treatment.