Bacteriophage penetration in vertebrates

... Bacteriophages are viruses that infect bacteria. They are the most numerous life forms on earth. As antibiotic resistance is becoming an increasingly worldwide challenge, bacteriophages as potential antimicrobial agents are being more intensively explored. Some very important questions involve their ability to penetrate higher organisms, as this determines potential phage activity in antibacterial treatment. Higher organisms are widely exposed to bacteriophages, which penetrate them quite freely. Bacteriophage activity can be influenced by specific antibodies which, together with the nonspecific immune system, can contribute to their rapid clearance from the organism. Bacteriophages can also interact directly with mammalian cells and even play a role in the development of some nonbacterial diseases, although they are not able to multiply in these cells. All aspects of the interaction between phages and higher organism are of interest and importance for further medical and biochemical applications. Bacteriophages are viruses that infect bacteria. Their general nature is similar to other viruses in that they consist of a piece of genetic information (nucleic acid) and a protein coat, some containing lipids in their coats or envelopes. They require a sensitive host with a specific receptor in order to replicate in the host cells. Over 5100 phages have been examined under electron microscopy since 1959. The groups of bacteriophages are varied, with DNA‐ and RNA‐phages, phages of different morphology, size, etc. At least 4950 phages (96%) are tailed and constitute the order Caudovirales and the three families Siphoviridae, Myoviridae and Podoviridae. Polyhedral, filamentous and pleomorphic phages comprise <4% of bacterial viruses (Ackermann and Gershman 1992; Doskar et al. 2000; Ackermann 2001, 2003).