## 1 Introduction  
Bacteriophages (phages) have come into increasing prominence since there are viruses of bacteria [1, 2]. Phages as antibacterial agents can be used to treat environments, both clinically or veterinary. The treatment can be described as phage-mediated bacterial biocontrol [3, 4], phage therapy, or bacterial therapy [5, 6]. The application of antibiotics to environments or the use of antibiotics normally employed as treatments of human infections for other means, such as in animal husbandry, has been discouraged [7, 8]. Thereby, it has become important to find alternatives to antibiotics to control undesirable bacteria [9, 10, 11, 12, 13]. Sulfate-reducing bacteria (SRB) are a group of anaerobic microorganisms that can be present in the environment and gastrointestinal tract as a part of the intestinal microbiome and can be involved in inflammatory bowel diseases (IBDs), including ulcerative colitis in the human and animals [14; 15; 16; 17; 18; 19]. They play an important role in this environmental sulfur cycle, especially in the dissimilarity sulfate reduction process. Sulfur belongs to group 16 of the periodic element system, and it makes up to 0.04% of the Earth's crust [20]. Though \(\approx\)100-fold less abundant than oxygen, sulfur nevertheless plays an important role in biology. Most prominently, sulfur is found as a component of two of the naturally occurring amino acids. These two, methionine and cysteine, are both essential to the functioning of all living organisms and play unique roles in both molecular genetics and protein structure, serving as start codons and disulfide bridges, respectively. Sulfur is found as well as an abiotic component of environments. For example, it contributes to the formation of the minerals pyrite (FeS\({}_{2}\)) and gypsum (CaSO\({}_{4}\):2H\({}_{2}\)O). Biogeochemically, sulfur can take on multiple forms involved in chemical and biological oxidation and reduction, since its oxidation numbers range from \(-2\) in the fully reduced state to +6 in the fully oxidized state [21]. Thus, sulfur in different forms can readily serve as electron donors (biologically, these are sources of energetic elections) and electron receptors, thus serving in this latter case as electron sinks, including as analogous to the role of oxygen as a final electron acceptor [22]. SRB are widely distributed in anoxic environments where they utilize sulfate as a terminal electron acceptor, reducing them to sulfides [23; 24; 25; 26; 27]. They inhabit terrestrial and aquatic ecosystems, and they are part of the microbiota of animals and humans [28; 29; 30; 31; 32]. As decomposed organic substances serve as the electron donor, SRB thereby represent chemotherapeutic, anaerobically respiring bacteria. The metabolite that results from this anaerobic respiration is known as hydrogen sulfide (H\({}_{2}\)S), and it is chemically analogous to water as the metabolic byproduct of aerobic respiration (water (H\({}_{2}\)O)). Unlike water, which represents hydrogen's most commonly fully oxidized state, H\({}_{2}\)S can still be oxidized by sulfur bacteria, serving in this case as an energy-carrying electron donor. H\({}_{2}\)S also can be released into the atmosphere as hydrogen sulfide gas [22]. H\({}_{2}\)S production and release in the course of anaerobic respiration of SRB causes a wide range of issues. For example, SRB found in marine sediments are the cause of sulfur presence in petroleum, generating so-called \"sour\" crude oil vs. the preferred \"sweet\" crude oil. SRB-released H\({}_{2}\)S is associated as well with the corrosion of steel components of machines used during oil extraction, transport, and processing [33]. In addition, SRB are part of the human and animal intestinal microbiome. _Desulfomonas pigra_, now called _Desulfovibrio piger_, was first isolated in 1976 as the part of the intestinal microbiome [34].