Piperacillin and ceftazidime produce the strongest synergistic phage-antibiotic effect in Pseudomonas aeruginosa.

The combined use of phage and antibiotics can show synergistic antimicrobial effects, so-called phage-antibiotic synergy (PAS). Here, we screened and examined PAS against Pseudomonas aeruginosa in vitro. Testing four different phages infecting P. aeruginosa, phage KPP22 classified within the family Myoviridae genus Pbunavirus showed PAS with the widest range of antibiotics, and showed PAS with anti-Pseudomonas drugs such as piperacillin and ceftazidime. Thus, evidence suggests that the combined use of phage and antibiotics is a promising therapeutic strategy against P. aeruginosa infections, with consideration needed regarding the optimal selection and adequate application timing of these phages and antibiotics.