Synergistic antimicrobial activity of bacteriophages and antibiotics against Staphylococcus aureus

초록

This study was designed to assess the synergistic antimicrobial effect of phages combined with antibiotics against Staphylococcus aureus. The phage-antibiotic synergy (PAS) effect was evaluated using the fractional inhibitory concentration (FIC) and flow cytometric analysis. The determined minimum inhibitory concentration (MIC) values varied from 0.125 to 128 mu g/mL for S. aureus KACC 13236 (SA(S)) and from 0.25 to > 256 mu g/mL for S. aureus CCARM 3080 (SA(R)). The PAS effect was more pronounced in SA(S) treated with phage SA11 in the presence of cefoxitin (FIC=0.62), chloramphenicol (FIC=0.54), and polymyxin B (FIC=0.38). SA(S) and SA(R) cells were injured when exposed to asublethal concentration of ciprofloxacin, whereas these cells were highly susceptible to the phage-antibiotic combined treatment, showing 96% of relative percentages of injured and dead cells. The results suggest that the combined treatment of phages and antibiotics can be used to improve antimicrobial efficacy against antibiotic-resistant bacteria.

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