Phage viruses, or bacteriophages, are a type of virus that specifically infects and replicates within bacteria. They attach to bacterial cells, inject their genetic material, and hijack the bacterial machinery to produce new phage particles. This process often leads to the destruction of the bacterial cell, releasing new phages to infect other bacteria. Phages are found in various environments, including soil and water, and play a crucial role in regulating bacterial populations. They are being researched for potential applications in medicine, particularly in treating bacterial infections that are resistant to antibiotics, highlighting their importance in the field of microbiology.