The issue of antibiotic resistance in healthcare worldwide has led to a pressing need to explore and develop alternative approaches to combat infectious diseases. Among these methods, phage therapy has emerged as a potential solution to tackle this growing challenge. Virulent phages of the Herelleviridae family, known for their ability to cause lysis of Staphylococcus aureus, a clinically significant pathogen frequently associated with multidrug resistance, have proven to be one of the most effective viruses utilized in phage therapy. In order to utilize phages for therapeutic purposes effectively, a thorough investigation into their physiology and mechanisms of action on infected cells is essential. The use of omics technologies, particularly total RNA sequencing, is a promising approach for analyzing the interaction between phages and their hosts, allowing for the assessment of both the behavior of the phage during infection and the cell’s response. This review aims to provide a comprehensive overview of the physiology of the Herelleviridae family, utilizing existing analyses of their total phage transcriptomes. Additionally, it sheds light on the changes that occur in the metabolism of S. aureus when infected with virulent bacteriophages, contributing to a deeper understanding of the phage–host interaction.

Bacteriophage therapy, which employs bacterial viruses to selectively eliminate pathogenic bacteria, has re-emerged as a promising strategy in the face of increasing antimicrobial resistance. However, its widespread clinical implementation is constrained by concerns regarding safety, standardisation, and predictable efficacy. In this review, we examine the key role of genomics in transforming phage therapy from an empirical practice into a standardised and personalised modality of contemporary medicine. We describe how whole-genome sequencing (WGS) provides a basis for safety assessment by enabling systematic screening to exclude virulence factors, antibiotic resistance genes, and markers of lysogeny. WGS also facilitates the prediction of therapeutic efficacy and supports more rational phage selection by identifying receptor-binding proteins and characterising bacterial defence systems. In clinical settings, WGS data are increasingly used to monitor the evolution of bacterial populations and to adapt phage cocktails during treatment, thereby supporting personalised, adaptive phage therapy. Looking ahead, further progress is likely to come from integrating synthetic biology and artificial intelligence to engineer phage-based therapeutics with programmable specificity and predictable properties. Together, these developments are shaping a new paradigm of phage therapy as a scientifically grounded, standardised and controlled strategy to treat infections caused by antibiotic-resistant bacteria.

The combined use of lytic bacteriophages with antibiotics is currently being explored as a strategy to enhance the effectiveness of infectious disease therapies, including those caused by Staphylococcus aureus. In this study, we investigated the synergistic potential of bacteriophage vB_SauM-515A1 (Herelleviridae family) and the first-line antibiotic linezolid against the methicillin-resistant S. aureus strain SA0413Rev. A checkerboard assay revealed a significant synergistic effect against planktonic cells (FIC = 0.225): a combination of 1/8 MIC of linezolid and 0.01 MOI of the bacteriophage completely inhibited bacterial growth. However, the impact on biofilm-associated cells depended on the treatment sequence. Sequential administration resulted in antagonism, while simultaneous application demonstrated a synergistic effect, as confirmed through scanning electron microscopy. Transcriptomic analysis of S. aureus SA0413Rev under the combined influence of linezolid (1/4 MIC) and bacteriophage vB_SauM-515A1 (10 MOI) predominantly reflected changes associated with productive bacteriophage infection, including alterations in nucleotide metabolism, activation of prophage regions, and virulence factors. Furthermore, both agents affected energy and carbon metabolism. These findings contribute to the development of combination therapy approaches for infections caused by S. aureus and highlight the importance of optimizing treatment conditions for maximal therapeutic efficacy.

Staphylococcus aureus causes a broad range of infections and is often characterized by multidrug resistance (MDR). Treatment of staphylococcal infections is further complicated by the ability of bacterium to form biofilms protecting it against antimicrobial agents and the immune system. The use of bacteriophages is one of the promising strategies for combating the bacteria showing MDR and biofilm formation activity. The study aimed to assess the effects of the lytic phages vB_SauM515A1 (genus Kayvirus, family Herelleviridae) and vB_SauP-436A (genus Rosenblumvirus, family Rountreeviridae) on biofilms of the S. aureus clinical strains. The study involved 20 strains of eight sequence types, among which 45% (9/20) belonged to MRSA, and 35% (7/20) showed MDR. All the strains demonstrated the ability to form biofilms, and 65% (13/20) were strong biofilm producers. Genes of the icaADBC operon responsible for synthesis of polysaccharide intercellular adhesin were found in genomes of all samples. The exposure of planktonic bacterial cells to bacteriophages showed that 70% (14/20) of strains were sensitive to phage vB_SauM-515A1 and 50% (10/20) were sensitive to phage vB_SauP-436A. Furthermore, the 24-h treatment of biofilms of sensitive strains with phage vB_SauM-515A1 led to the biofilm biomass increase in 64.3% (9/14) of cases, while phage vB_SauP-436A, on the contrary, significantly reduced the quantity of biofilm in 40% (4/10) of strains. The results obtained highlight the ambiguity of interaction between bacteriophages and S. aureus biofilms and suggest the need for further research aimed at optimizing phage therapy targeting the biofilm-forming strains.

Introduction. Klebsiella pneumoniae poses a serious threat to global healthcare due to the high proportion of multidrug-resistant isolates. Moreover, the formation of biofilms by bacteria significantly complicates the treatment of infections.Objective. To evaluate the effectiveness of the individual and combined action of antibiotics and bacteriophages or polysaccharide depolymerase on biofilms of a clinically significant strain K. pneumoniae.Materials and methods. The work used the K. pneumoniae strain with multidrug resistance (9faiz), 4 antibiotics of various classes (gentamicin, levofloxacin, meropenem and chloramphenicol), 3 bacteriophages of various genera (Dlv622, Seu621 and FRZ284), and 1 polysaccharide depolymerase (Dep622). Experiments were carried out on the formed biofilms by treating 24-hour K. pneumoniae films with antimicrobial agents individually or in combinations. The ability of the strain to form biofilms was evaluated by staining with crystalline violet. The comparison between the average optical density values was carried out using a t-test and was considered significant at p ≤ 0.05.Results. The individual use of antibiotics peak concentrations (C_max) or depolymerase concentration of 100 MED (minimum effective dose — MED) did not lead to a significant decrease in biofilm biomass, whereas bacteriophages in a titer of 5×10⁹ PFU/mL (plaque-forming unit per mL) statistically significantly reduced its biomass by 27–31% (p < 0.05) Most combinations of phages and antibiotics did not lead to a significant increase in the efficiency of biofilm destruction. Only the combination of phage FRZ284 with gentamicin statistically significantly showed an additional decrease in biofilm biomass by 27% (p < 0.05).Conclusions. The results show the need for individual selection of antimicrobial combinations to combat K. pneumoniae biofilms due to the possible effect of synergy and antagonism effects on the outcome of therapy.