Life-threatening human infectious diseases caused by bacterial pathogens are now re-emerging, in part due to the increased resistance to antibiotics. Antibiotics are non-specific, they can target a wide group of bacteria, perturbing our natural microbiota. This fact, besides contributing to increase the antibiotic resistance, compromises our health. To address this problem, we propose a new approach of personalized therapy based on the antibacterial properties of certain viruses, called bacteriophages (phages).