Co-Infection in COVID-19 Patients: Virulence Genes and Their Influence on Respiratory Epithelial Cells in Light of Risk of Severe Secondary Infection.

Pandemics from viral respiratory tract infections in the 20th and early 21st centuries were associated with high mortality, which was not always caused by a primary viral infection. It has been observed that severe course of infection, complications and mortality were often the result of co-infection with other pathogens, especially . During the COVID-19 pandemic, it was also noticed that patients infected with had a significantly higher mortality rate (61.

Complex effects of the exo-xis region of the Shiga toxin-converting bacteriophage Φ24 genome on the phage development and the Escherichia coli host physiology.

Lambdoid bacteriophages are excellent models in studies on molecular aspects of virus-host interactions. However, some of them carry genes encoding toxins which are responsible for virulence of pathogenic strains of bacteria. Shiga toxin-converting bacteriophages (Stx phages) encode Shiga toxins that cause virulence of enterohemorrhagic Escherichia coli (EHEC), and their effective production depends on Stx prophage induction.

Propagation, Purification, and Characterization of Bacteriophages for Phage Therapy.

Phage therapy is an alternative approach to combat bacterial infections. In this approach, bacteriophages are used as antimicrobial agents due to their properties to infect specific bacterial cells, to propagate inside their hosts, and to lyse host cell to release progeny phages. However, to introduce bacteriophages to clinical or veterinary practice, it is necessary to construct a large library of precisely characterized phages.

Biological aspects of phage therapy versus antibiotics against serovar Typhimurium infection of chickens.

Phage therapy is a promising alternative treatment of bacterial infections in human and animals. Nevertheless, despite the appearance of many bacterial strains resistant to antibiotics, these drugs still remain important therapeutics used in human and veterinary medicine. Although experimental phage therapy of infections caused by was described previously by many groups, those studies focused solely on effects caused by bacteriophages.

Synergistic Effects of Bacteriophage vB_Eco4-M7 and Selected Antibiotics on the Biofilm Formed by Shiga Toxin-Producing .

Apart from antibiotic resistance of pathogenic bacteria, the formation of biofilms is a feature that makes bacterial infections especially difficulty to treat. Shiga toxin-producing (STEC) strains are dangerous pathogens, causing severe infections in humans, and capable of biofilm production. We have reported previously the identification and characterization of the vB_Eco4-M7 bacteriophage, infecting various STEC strains.

A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Contamination.

Shiga toxin-producing (STEC) can cause severe infections in humans, leading to serious diseases and dangerous complications, such as hemolytic-uremic syndrome. Although cattle are a major reservoir of STEC, the most commonly occurring source of human infections are food products (e.g.

Phage-Bacteria Interactions in Potential Applications of Bacteriophage vB_EfaS-271 against .

Phage therapy is one of main alternative option for antibiotic treatment of bacterial infections, particularly in the era of appearance of pathogenic strains revealing resistance to most or even all known antibiotics. is one of such pathogens causing serious human infections. In the light of high level of biodiversity of bacteriophages and specificity of phages to bacterial species or even strains, development of effective phage therapy depend, between others, on identification and characterization of a large collection of these viruses, including understanding of their interactions with host bacterial cells.

Bacteriophage-Derived Depolymerases against Bacterial Biofilm.

In addition to specific antibiotic resistance, the formation of bacterial biofilm causes another level of complications in attempts to eradicate pathogenic or harmful bacteria, including difficult penetration of drugs through biofilm structures to bacterial cells, impairment of immunological response of the host, and accumulation of various bioactive compounds (enzymes and others) affecting host physiology and changing local pH values, which further influence various biological functions. In this review article, we provide an overview on the formation of bacterial biofilm and its properties, and then we focus on the possible use of phage-derived depolymerases to combat bacterial cells included in this complex structure. On the basis of the literature review, we conclude that, although these bacteriophage-encoded enzymes may be effective in destroying specific compounds involved in the formation of biofilm, they are rarely sufficient to eradicate all bacterial cells.

Characterization of a bacteriophage, vB_Eco4M-7, that effectively infects many Escherichia coli O157 strains.

The characterization of a recently isolated bacteriophage, vB_Eco4M-7, which effectively infects many, though not all, Escherichia coli O157 strains, is presented. The genome of this phage comprises double-stranded DNA, 68,084 bp in length, with a GC content of 46.2%.

The ea22 gene of lambdoid phages: preserved prolysogenic function despite of high sequence diversity.

The exo-xis region of lambdoid phages contains open reading frames and genes that appear to be evolutionarily important. However, this region has received little attention up to now. In this study, we provided evidence that ea22, the largest gene of this region, favors the lysogenic pathway over the lytic pathway in contrast to other characterized exo-xis region genes including ea8.

Role of orf73 in the development of lambdoid bacteriophages during infection of the Escherichia coli host.

Shiga toxin-producing Escherichia coli (STEC) is a group of pathogenic strains responsible for human infections that result in bloody diarrhea and hemorrhagic colitis, often with severe complications. The main virulence factors of STEC are Shiga toxins encoded by stx genes located in genomes of Shiga toxin-converting bacteriophages (Stx phages). These bacterial viruses are clustered in the lambdoid bacteriophages family represented by phage λ.

Characterization of Bacteriophage vB-EcoS-95, Isolated From Urban Sewage and Revealing Extremely Rapid Lytic Development.

Morphological, biological, and genetic characteristics of a virulent phage, named vB-EcoS-95, is reported. This phage was isolated from urban sewage. It was found to infect some strains giving clear plaques.

Roles of and in Development of Bacteriophages λ and Φ24.

The region of lambdoid bacteriophage genomes contains several established and potential genes that are evolutionarily conserved, but not essential for phage propagation under laboratory conditions. Nevertheless, deletion or overexpression of either the whole region and important regulatory elements can significantly influence the regulation of phage development. This report defines specific roles for and in bacteriophage λ and Φ24, a specific Shiga toxin-converting phage with clinical relevance.

Bad Phages in Good Bacteria: Role of the Mysterious of λ and Shiga Toxin-Converting Φ24 Bacteriophages.

Lambdoid bacteriophages form a group of viruses that shares a common schema of genome organization and lifecycle. Some of them can play crucial roles in creating the pathogenic profiles of strains. For example, Shiga toxin-producing (STEC) acquired genes, encoding Shiga toxins, via lambdoid prophages (Stx phages).

Biodiversity of bacteriophages: morphological and biological properties of a large group of phages isolated from urban sewage.

A large scale analysis presented in this article focuses on biological and physiological variety of bacteriophages. A collection of 83 bacteriophages, isolated from urban sewage and able to propagate in cells of different bacterial hosts, has been obtained (60 infecting Escherichia coli, 10 infecting Pseudomonas aeruginosa, 4 infecting Salmonella enterica, 3 infecting Staphylococcus sciuri, and 6 infecting Enterococcus faecalis). High biological diversity of the collection is indicated by its characteristics, both morphological (electron microscopic analyses) and biological (host range, plaque size and morphology, growth at various temperatures, thermal inactivation, sensitivity to low and high pH, sensitivity to osmotic stress, survivability upon treatment with organic solvents and detergents), and further supported by hierarchical cluster analysis.

UV-Sensitivity of Shiga Toxin-Converting Bacteriophage Virions Φ24B, 933W, P22, P27 and P32.

Shiga toxin-converting bacteriophages (Stx phages) are present as prophages in Shiga toxin-producing Escherichia coli (STEC) strains. Theses phages can be transmitted to previously non-pathogenic E. coli cells making them potential producers of Shiga toxins, as they bear genes for these toxins in their genomes.