Bacteriophage therapy against staphylococci

Structure and host specificity of Staphylococcus epidermidis bacteriophage Andhra

Staphylococcus epidermidis is an opportunistic pathogen of the human skin, often associated with infections of implanted medical devices. Staphylococcal picoviruses are a group of strictly lytic, short-tailed bacteriophages with compact genomes that are attractive candidates for therapeutic use. Here, we report the structure of the complete virion of S. epidermidis-infecting phage Andhra, determined using high-resolution cryo-electron microscopy, allowing atomic modeling of 11 capsid and tail proteins. The capsid is a T = 4 icosahedron containing a unique stabilizing capsid lining protein. The tail includes 12 trimers of a unique receptor binding protein (RBP), a lytic protein that also serves to anchor the RBPs to the tail stem, and a hexameric tail knob that acts as a gatekeeper for DNA ejection. Using structure prediction with AlphaFold, we identified the two proteins that comprise the tail tip heterooctamer. Our findings elucidate critical features for virion assembly, host recognition, and penetration.

Isolation of a Novel Lytic Bacteriophage against a Nosocomial Methicillin-Resistant Staphylococcus aureus Belonging to ST45

Methicillin-resistant Staphylococcus aureus (MRSA) can cause a wide range of infections from mild to life-threatening conditions. Its enhanced antibiotic resistance often leads to therapeutic failures and therefore alternative eradication methods must be considered. Potential candidates to control MRSA infections are bacteriophages and their lytic enzymes, lysins. In this study, we isolated a bacteriophage against a nosocomial MRSA strain belonging to the ST45 epidemiologic group. The phage belonging to Caudovirales, Siphoviridae, showed a narrow host range and stable lytic activity without the emergence of resistant MRSA clones. Phylogenetic analysis showed that the newly isolated Staphylococcus phage R4 belongs to the Triavirus genus in Siphoviridae family. Genetic analysis of the 45 kb sequence of R4 revealed 69 ORFs. No remnants of mobile genetic elements and traces of truncated genes were observed. We have localized the lysin (N-acetylmuramoyl-L-alanine amidase) gene of the new phage that was amplified, cloned, expressed, and purified. Its activity was verified by zymogram analysis. Our findings could potentially be used to develop specific anti-MRSA bacteriophage- and phage lysin-based therapeutic strategies against major clonal lineages and serotypes.

Fahotyp and Sensitivity to Medications Phage Film-Forming Strains <i>Staphylococcus aureus</i>, Isolated from Respiratory Tract

The study of biological properties of filmforming Staphylococcus aureus strains, including its sensitivity to bacteriophages, is one of the important tasks of laboratory diagnostic service that allows, if it necessary, choose an alternative treatment strategy and to establish the sources of strains. In the study of material from the nose and throat of 26 persons-volunteers the strains of S. aureus were selected. Among them 16 (61.5%) were able to form biofilms. Analysis of resistance to phages drugs of filmformation strains of S. aureus showed that 87.5% strains were sensitive the phages drugs "Piobacteriophage" and "Bacteriophage staphylococcal liquid". Phage type was identified for 9 (56.3%) strains. 64.3% of these strains were sensitive to the 1 phage from set, 21.4% – to 2 and 14.3% – 3 phages. It was determined that 77.8% strains were typed by phages from third group. For 1 strain detected simultaneous sensitivity to phages of 2 and 3 groups. With phage 81 (out of group phage) interacted 4 strains: 2 showed sensitivity only to him and another 2 were also susceptible to phage of third group.

Fahotyp and Sensitivity to Medications Phage Film-Forming Strains <i>Staphylococcus aureus</i>, Isolated from Respiratory Tract

The study of biological properties of filmforming Staphylococcus aureus strains, including its sensitivity to bacteriophages, is one of the important tasks of laboratory diagnostic service that allows, if it necessary, choose an alternative treatment strategy and to establish the sources of strains. In the study of material from the nose and throat of 26 persons-volunteers the strains of S. aureus were selected. Among them 16 (61.5%) were able to form biofilms. Analysis of resistance to phages drugs of filmformation strains of S. aureus showed that 87.5% strains were sensitive the phages drugs "Piobacteriophage" and "Bacteriophage staphylococcal liquid". Phage type was identified for 9 (56.3%) strains. 64.3% of these strains were sensitive to the 1 phage from set, 21.4% – to 2 and 14.3% – 3 phages. It was determined that 77.8% strains were typed by phages from third group. For 1 strain detected simultaneous sensitivity to phages of 2 and 3 groups. With phage 81 (out of group phage) interacted 4 strains: 2 showed sensitivity only to him and another 2 were also susceptible to phage of third group.

Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection

The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a “post-antibiotic era”, the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

Hemocompatible, antioxidative and antibacterial polypropylene prepared by attaching silver nanoparticles capped with TPGS

Synthesis of Ag NPs by TPGS and the excellent hemocompatibility, anti-oxidative and antibacterial properties of the deposition of Ag NPs onto PP grafted with NIPAAm and APMA.