Answer:
Bacteriophages are specialised viruses that only infect bacteria. Recently, bacteriophages have been tested on a patients in a critical condition. A patient was suffering from a bacterial infection in their chest cavity and the species of bacteria are naturally resistant to antibiotics and can even survive in alcoholic hand gel. The patient had no other hope left. So a few thousand bacteriophages were inserted in their chest cavity. After a few weeks the infection had completely disappeared.
