Currently, the bacterial resistance, especially to most commonly used antibiotics has proved to be a severe
therapeutic problem. Nosocomial and community-acquired infections are usually caused by multidrug resistant strains.
Therefore, we are forced to develop an alternative or supportive treatment for successful cure of life-threatening infections.
The idea of using natural bacterial pathogens such as bacteriophages is already well known. Many papers have been
published proving the high antibacterial efficacy of lytic phages tested in animal models as well as in the clinic. Researchers
have also investigated the application of non-lytic phages and temperate phages, with promising results. Moreover, the
development of molecular biology and novel generation methods of sequencing has opened up new possibilities in the design
of engineered phages and recombinant phage-derived proteins. Encouraging performances were noted especially for
phage enzymes involved in the first step of viral infection responsible for bacterial envelope degradation, named depolymerases.
There are at least five major groups of such enzymes – peptidoglycan hydrolases, endosialidases, endorhamnosidases,
alginate lyases and hyaluronate lyases – that have application potential. There is also much interest in proteins
encoded by lysis cassette genes (holins, endolysins, spanins) responsible for progeny release during the phage lytic cycle.
In this review, we discuss several issues of phage and phage-derived protein application approaches in therapy, diagnostics
and biotechnology in general.