Comparative Assessment of Bacteriophage and Antibiotic Activity against Multidrug-Resistant Staphylococcus aureus Biofilms

Problems connected with biofilm-related infections and antibiotic resistance necessitate the investigation and development of novel treatment strategies. Given their unique characteristics, one of the most promising alternatives to conventional antibiotics are bacteriophages. In the in vitro and in vivo larva model study, we demonstrate that phages vB_SauM-A, vB_SauM-C, and vB_SauM-D are effective antibiofilm agents. The exposure of biofilm to phages vB_SauM-A and vB_SauM-D led to 2-3 log reductions in the colony-forming unit number in most of the multidrug-resistant S. aureus strains. It was found that phage application reduced the formed biofilms independently of the used titer. Moreover, the study demonstrated that bacteriophages are more efficient in biofilm biomass removal and reduction in staphylococci count when compared to the antibiotics used. The scanning electron microscopy analysis results are in line with colony forming unit (CFU) counting but not entirely consistent with crystal violet (CV) staining. Additionally, phages vB_SauM-A, vB_SauM-C, and vB_SauM-D can significantly increase the survival rate and extend the survival time of Galleria mellonella larvae.

Automated summary

The investigation and development of novel treatment strategies are necessary to address problems related to biofilm-related infections and antibiotic resistance. Bacteriophages, as promising alternatives to conventional antibiotics, have been shown to be effective antibiofilm agents in both in vitro and in vivo larva model studies. The results demonstrate that phages vB_SauM-A, vB_SauM-C, and vB_SauM-D can effectively reduce the colony-forming unit number of multidrug-resistant S. aureus strains in biofilms, independently of the phage titer used. Furthermore, bacteriophages were found to be more efficient than antibiotics in removing biofilm biomass and reducing staphylococci count. Additionally, phages vB_SauM-A, vB_SauM-C, and vB_SauM-D can enhance the survival rate and prolong the survival time of Galleria mellonella larvae.