The journal Current Opinion in Microbiology published a review devoted to the prospects for the combined use of bacteriophages and antibiotics in clinical practice. This issue is particularly relevant for the treatment of multidrug-resistant bacterial infections.

Experiments on cell cultures and animals have repeatedly demonstrated that antibiotics and phage preparations exhibit synergy when used together, meaning their combined effect exceeds the sum of the effects of each drug alone. Is a similar picture observed in clinical use? The authors of this review are confident that it is, but they have several caveats.

Thus, they indicate that the presence and degree of synergy between antimicrobial and phage drugs depends on both the bacteriophage strain and the antibiotic, therefore, for the widespread use of this combination in clinical practice, it is necessary to create convenient test systems that allow for the rapid determination of optimal agents for the treatment of a specific infection.

The reason for the synergy between antibiotics and bacteriophages remains unclear. Different antibiotics of the same class, when combined with the same bacteriophage, can exhibit different results against the same pathogen. In some cases, synergy can be explained by the fact that antibiotics are often ineffective against bacteria that form biofilms , whereas bacteriophages are capable of disrupting biofilms and allowing antibiotics access to their targets. In some cases, bacteriophages, by binding to proteins on the surface of bacteria, disrupt their virulence. Another aspect that may influence the effectiveness of combination therapy is the interaction of bacteriophages with the human or animal immune system , particularly their immunomodulatory effects.

Summarizing the available data, the authors note the need for further research into the potential of combined use of antibiotics and bacteriophages in the treatment of bacterial infections, as, in the absence of randomized clinical trials, each treatment is essentially experimental. The authors believe that the use of bacteriophages in clinical practice will improve the effectiveness of antibacterial therapy, which is declining dramatically due to the spread of resistant strains of microorganisms.

* Segall AM, Roach DR, Strathdee SA. Stronger together? Perspectives on phage-antibiotic synergy in clinical applications of phage therapy // Current Opinion in Microbiology, 2019, 51: 46-50. https://doi.org/10.1016/j.mib.2019.03.005