Bacteriophage Therapy Against Antibiotic-Resistant Bacteria: A Critical Appraisal

Bacteriophages are bacteria-specific viruses that reduce or eliminate pathogenic or nuisance bacteria. It helps treat bacterial infections in animals, humans, birds, fish, plants, and food materials. All phages have a head structure that can vary in size and shape. When a virulent phage infects a host bacterium, it replicates much faster than the host cell does, causes lysis and death, simultaneously liberating many progeny phages for another cycle by infecting new neighboring bacterial cells. Phages can be administered orally, topically, in drops, intravenously, or via inhalation. After a single dose, phages are resorbed and reach the bloodstream within 2–4 h and the internal organs within a duration of 10 h, eventually being eliminated from the body within three days. Phage therapy can be used in many animals, including poultry, swine, cattle, and sheep, to treat various bacterial diseases caused by Salmonella, Escherichia coli, and Campylobacter. In modern technology, bacteriophages are genetically modified and engineered in such a way as to capacitate the expression of proteins and target the gene networks of bacteria on which antibiotics fail to act directly. The potential in vivo elimination of phages, phage-neutralizing antibodies, reticuloendothelial system clearance of phages from the patients, and phage-resistant mutants are the major limitations of phages. However, bacteriophages offer several advantages over antibiotics, including high host specificity. Therefore, phage therapy is a promising alternative for mitigating the burden of antibiotic-resistant bacteria.