New Phages Brutus and Scipio: Biology, Evolution, and Phage-Host Interaction.

Two novel virulent phages of the genus infecting , a significant nosocomial pathogen, have been isolated and studied. Phages Brutus and Scipio were able to infect strains belonging to the K116 and K82 capsular types, respectively. The biological properties and genomic organization of the phages were characterized.

Depolymerisation of the Capsular Polysaccharide K21 by Klebsiella Phage K5.

is a pathogen associated with various infection types, which often exhibits multiple antibiotic resistance. Phages, or bacterial viruses, have an ability to specifically target and destroy , offering a potential means of combatting multidrug-resistant infections. Phage enzymes are another promising therapeutic agent that can break down bacterial capsular polysaccharide, which shields from the immune response and external factors.

5,7-Diamino-3,5,7,9-tetradeoxynon-2-ulosonic Acids in the Capsular Polysaccharides of Acinetobacter baumannii.

The polysaccharide capsule surrounding bacterial cell plays an important role in pathogenesis of infections caused by the opportunistic pathogen Acinetobacter baumannii by providing protection from external factors. The structures of the capsular polysaccharide (CPS) produced by A. baumannii isolates and the corresponding CPS biosynthesis gene clusters are highly diverse, although many of them are related.

Bacteriophage Possum: A Complex Polysaccharide-Deacetylating Tail Fiber as a Tool for Host Recognition in Pectobacterial .

Novel, closely related phages Possum and Horatius infect , a phytopathogen causing soft rot in potatoes and other essential plants. Their properties and genomic composition define them as N4-like bacteriophages of the genus , a part of a recently formed family . It is proposed that the adsorption apparatus of these phages consists of tail fibers connected to the virion through an adapter protein.

Comparison of the therapeutic potential of bacteriophage KpV74 and phage-derived depolymerase (β-glucosidase) against Klebsiella pneumoniae capsular type K2.

Bacteriophages and phage polysaccharide-degrading enzymes (depolymerases) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of bacteriophage KpV74 and phage depolymerase Dep_kpv74 specific to the hypervirulent Klebsiella pneumoniae of the K2 capsular type. The depolymerase Dep_kpv74 was identified as a specific glucosidase that cleaved the K2 type capsular polysaccharides of the K.

The K139 capsular polysaccharide produced by Acinetobacter baumannii MAR17-1041 belongs to a group of related structures including K14, K37 and K116.

Capsular polysaccharide (CPS) is a key target for bacteriophage and vaccine therapies currently being developed for treatment of infections caused by the extensively antibiotic resistant bacterial species, Acinetobacter baumannii. Identification of new CPS structures and the genetics that drive their synthesis underpins tailored treatment strategies. A novel CPS biosynthesis gene cluster, designated KL139, was identified in the whole genome sequence of a multiply antibiotic resistant clinical isolate, A.

Correlation of Acinetobacter baumannii K144 and K86 capsular polysaccharide structures with genes at the K locus reveals the involvement of a novel multifunctional rhamnosyltransferase for structural synthesis.

Whole genome sequence from Acinetobacter baumannii isolate Ab-46-1632 reveals a novel KL144 capsular polysaccharide (CPS) biosynthesis gene cluster, which carries genes for d-glucuronic acid (D-GlcA) and l-rhamnose (l-Rha) synthesis. The CPS was extracted from Ab-46-1632 and studied by H and C NMR spectroscopy, including a two-dimensional H,C HMBC experiment and Smith degradation. The CPS was found to have a hexasaccharide repeat unit composed of four l-Rhap residues and one residue each of d-GlcpA and N-acetyl-d-glucosamine (D-GlcpNAc) consistent with sugar synthesis genes present in KL144.

Characterization and Therapeutic Potential of Bacteriophage-Encoded Polysaccharide Depolymerases with β Galactosidase Activity against K57 Capsular Type.

Bacteriophages and phage enzymes are considered as possible alternatives to antibiotics in the treatment of infections caused by antibiotic-resistant bacteria. Due to the ability to cleave the capsular polysaccharides (CPS), one of the main virulence factors of , phage depolymerases, has potential in the treatment of infections. Here, we characterized in vivo two novel phage-encoded polysaccharide depolymerases as therapeutics against clinical isolates of .

Bacteriophage Arno 160 Infects via Depolymerization of the Bacterial O-Polysaccharide.

Phytopathogenic bacteria belonging to the and genera (soft-rot ) are in the focus of agriculture-related microbiology because of their diversity, their substantial negative impact on the production of potatoes and vegetables, and the prospects of bacteriophage applications for disease control. Because of numerous amendments in the taxonomy of , there are still a few studied sequenced strains among this species. The present work reports on the isolation and characterization of the phage infectious to the type strain of .

Morphologically Different Bacteriophages PP99 and PP101: Deacetylation of O-Polysaccharide by the Tail Spike Protein of Phage PP99 Accompanies the Infection.

Soft rot caused by numerous species of and is a serious threat to the world production of potatoes. The application of bacteriophages to combat bacterial infections in medicine, agriculture, and the food industry requires the selection of comprehensively studied lytic phages and the knowledge of their infection mechanism for more rational composition of therapeutic cocktails. We present the study of two bacteriophages, infective for the strain F152.

Structure and gene cluster of the capsular polysaccharide of multidrug resistant carbapenemase OXA-48-producing Klebsiella pneumoniae strain KPB536 of the genetic line ST147.

The Gram-negative opportunistic pathogen Klebsiella pneumoniae is a significant cause of community-acquired and healthcare-associated infections for which multidrug resistance is a concern worldwide. A major virulence determinant of K. pneumoniae is a polysaccharide capsule (CPS) which forms a barrier around the bacterial cell wall, providing protection from environmental pressures and immune responses of eukaryotic organisms.

Identification serologically, chemically and genetically of two Escherichia coli strains as candidates for new O serogroups.

Escherichia coli strains are normally identified by the combination of their O and H (and sometimes K) antigens, and serotyping based on the antigens is believed to be crucial for clinical detection and epidemiological investigation. Two E. coli strains, G5413 and G5287, were isolated from faecal samples of female patients with diarrhoea and were not agglutinated with any antisera that cover the well-known O serogroups of E.

Structure of the O-polysaccharide of Providencia alcalifaciens O2 containing ascarylose and N-(L-alanyl)-D-glucosamine.

The O-polysaccharide was obtained by degradation of the lipopolysaccharide of Providencia alcalifaciens O2 under mild acidic conditions followed by GPC. The polysaccharide was found to contain two unusual components: 3,6-dideoxy-L-arabino-hexose (ascarylose, Asc) and 2-(L-alanyl)amino-2-deoxy-D-glucose (GlcNAla). Ascarylose was partially split off during lipopolysaccharide degradation and could be eliminated completely by selective acid hydrolysis, which also partially cleaved the β-GAlNAc-(1 → 6) linkage.

Genetic and structural identification of an O-acyltransferase gene (oacC) responsible for the 3/4-O-acetylation on rhamnose III in Shigella flexneri serotype 6.

Background: O-antigen (O-polysaccharide) of the lipopolysaccharide is a highly variable cell component of the outer membrane in Shigella flexneri. It defines the serospecificity and plays an important role in the pathogenesis of shigellosis. There are two distinct O-antigen forms for the 19 serotypes of S.

Chemical synthesis of polyprenyl sialyl phosphate, a probable biosynthetic intermediate of bacterial polysialic acid.

Using reaction of moraprenyl phosphate with the known N-acetylsialyl chloride and the novel N,N-diacetylsialyl (Neu5Ac(2)) chloride α- and β-anomers of polyprenyl sialyl phosphate were synthesized for the first time. The α-selectivity dramatically increased when Neu5Ac(2) chloride was used as the glycosyl donor.

N,N-Diacetylsialyl chloride--a novel readily accessible sialyl donor in reactions with neutral and charged nucleophiles in the absence of a promoter.

N,N-Diacetylneuraminic acid glycosyl chloride was prepared for the first time and made to react with various nucleophiles to give the corresponding alpha-glycosyl phosphate, beta-glycosyl dibenzyl phosphate, alpha-glycosyl azide, alpha-phenyl thioglycoside and alpha-glycosyl xanthate in 65-82% yields and high stereoselectivity while its reactions with simple alcohols were not stereoselective. The new sialyl donor made possible the first stereoselective synthesis of sialic acid glycosyl phosphate with alpha-configuration and highly efficient synthesis of beta-configured sialic acid glycosyl dibenzyl phosphate.

Use of methanesulfonic acid in the reductive ring-opening of O-benzylidene acetals.

Methanesulfonic acid was shown to be an efficient and convenient substitute for ethereal HCl in reductive 4,6-O-benzylidene acetal ring-opening reaction with sodium cyanoborohydride in THF. Normal regioselectivity was observed, the 6-O-benzyl ethers with free 4-OH group being the major products of the reaction.