Comparison of methods for Phage-Antibiotic Synergy (PAS) detection
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| Year of publication | 2023 |
| Type | Conference abstract |
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| Description | The phenomenon of synergy between phages and antibiotics (PAS) and its use in phage therapy has been a much-discussed topic over the last ten years. Unfortunately, there is still no uniform definition of this concept. Synergies may include a larger phage burst size in the presence of antibiotics, an increase in the number or diameter of phage plaques, a faster onset of lysis, or more efficient eradication of bacteria. More effective eradication also includes the absence of resistant small colony variants. It is rare to see all manifestations at once, probably due to the different mechanisms of the PAS effect. We focused on staphylococcal phage P68 with podoviral morphology and an antibiotic affecting cell wall development, amoxicillin. Their combined effect was assessed by modified plaque assay, one-step growth curve, spectrophotometry in 96-well format or higher volumes in personal bioreactors, and microcalorimetry. We confirmed the synergy between amoxicillin and phage P68 by spectrophotometry and plaque assays. The synergy resulted in increased plaque diameter and more efficient lysis. However, the static measurement conditions in a microcalorimeter resulted in lower bacterial titer compared to spectrophotometric measurements, which reduced the synergy effect. On the other hand, the environment in the microcalorimetric well should better simulate the in vivo conditions. This study brings new insights into the interaction of phages with antibiotics, which is crucial for their combined application as a treatment in the future. |
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