Lytic Capsule-Specific Bacteriophages Encoding Polysaccharide-Degrading Enzymes.

The genus comprises both environmental and clinically relevant species associated with hospital-acquired infections. Among them, is a critical priority bacterial pathogen, for which the research and development of new strategies for antimicrobial treatment are urgently needed. spp.

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.

Phage-Encoded Depolymerases Specific to Different Capsular Types of .

is a critical priority nosocomial pathogen that produces a variety of capsular polysaccharides (CPSs), the primary receptors for specific depolymerase-carrying phages. In this study, the tailspike depolymerases (TSDs) encoded in genomes of six novel Friunaviruses, APK09, APK14, APK16, APK86, APK127v, APK128, and one previously described phage, APK37.1, were characterized.

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.

Complete Genome Sequence of Klebsiella pneumoniae Bacteriophage KpS110, Encoding Five Tail-Associated Proteins with Putative Polysaccharide Depolymerase Domains.

We report the genome sequence of bacteriophage KpS110, which infects Klebsiella pneumoniae, a multidrug-resistant encapsulated bacterium that causes severe community-acquired and hospital-acquired infections. The phage genome is 156,801 bp, with 201 open reading frames. KpS110 is most closely related to phages of the family at the genome and proteome levels.

Complete chemical structure of the K135 capsular polysaccharide produced by Acinetobacter baumannii RES-546 that contains 5,7-di-N-acetyl-8-epipseudaminic acid.

A structurally diverse capsular polysaccharide (CPS) in the outer cell envelope plays an important role in the virulence of the important bacterial pathogen, Acinetobacter baumannii. More than 75 different CPS structures have been determined for the species to date, and many CPSs include isomers of a higher sugar, namely 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acid. Recently, a novel isomer having the d-glycero-l-manno configuration (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) has been identified in the CPS from A.

Capsule-Targeting Depolymerases Derived from Prophage Regions.

In this study, several different depolymerases encoded in the prophage regions of genomes have been bioinformatically predicted and recombinantly produced. The identified depolymerases possessed multi-domain structures and were identical or closely homologous to various proteins encoded in other genomes. This means that prophage-derived depolymerases are widespread, and different bacterial genomes can be the source of proteins with polysaccharide-degrading activities.

Novel Bacteriophage Aristophanes Encoding Structural Polysaccharide Deacetylase.

appears to be one of the most crucial nosocomial pathogens. A possible component of antimicrobial therapy for infections caused by extremely drug-resistant strains may be specific lytic bacteriophages or phage-derived enzymes. In the present study, we observe the biological features, genomic organization, and phage-host interaction strategy of novel virulent bacteriophage Aristophanes isolated on strain having K26 capsular polysaccharide structure.

Novel Myovirus TaPaz Encoding Two Tailspike Depolymerases: Characterization and Host-Recognition Strategy.

, one of the most significant nosocomial pathogens, is capable of producing structurally diverse capsular polysaccharides (CPSs) which are the primary receptors for bacteriophages encoding polysaccharide-degrading enzymes. To date, bacterial viruses specifically infecting strains belonging to more than ten various capsular types (K types) were isolated and characterized. In the present study, we investigate the biological properties, genomic organization, and virus-bacterial host interaction strategy of novel myovirus TaPaz isolated on the bacterial lawn of strain with a K47 capsular polysaccharide structure.

Complete Genome Sequence of Acinetobacter baumannii Phage BS46.

myovirus BS46 was isolated from sewage by J. S. Soothill in 1991.

K17 capsular polysaccharide produced by Acinetobacter baumannii isolate G7 contains an amide of 2-acetamido-2-deoxy-d-galacturonic acid with d-alanine.

The K17 capsular polysaccharide (CPS) produced by Acinetobacter baumannii G7, which carries the KL17 configuration at the capsule biosynthesis locus, was isolated and studied by chemical methods along with one- and two-dimensional H and C NMR spectroscopy. Selective cleavage of the glycosidic linkage of a 2,4-diacetamido-2,4,6-trideoxy-d-glucose (d-QuiNAc4NAc) residue by (i) trifluoroacetic acid solvolysis or (ii) alkaline β-elimination (NaOH-NaBH) of the 4-linked D-alanine amide of a 2-acetamido-2-deoxy-d-galacturonic acid residue (d-GalNAcA6DAla) yielded trisaccharides that were isolated by Fractogel TSK HW-40 gel-permeation chromatography and identified by using NMR spectroscopy and high-resolution electrospray ionization mass spectrometry. The following structure was established for the trisaccharide repeat (K unit) of the CPS: →4)-α-d-GalpNAcA6dAla-(1→4)-α-d-GalpNAcA-(1→3)-β-d-QuipNAc4NAc-(1→ .

Characterization of myophage AM24 infecting Acinetobacter baumannii of the K9 capsular type.

In the present study, we investigate the biological properties and genomic organization of virulent bacteriophage AM24, which specifically infects multidrug-resistant clinical Acinetobacter baumannii strains with a K9 capsular polysaccharide structure. The phage was identified as a member of the family Myoviridae by transmission electron microscopy. The AM24 linear double-stranded DNA genome of 97,177 bp contains 167 open reading frames.

Production of the K16 capsular polysaccharide by Acinetobacter baumannii ST25 isolate D4 involves a novel glycosyltransferase encoded in the KL16 gene cluster.

A new capsular polysaccharide (CPS) biosynthesis gene cluster, KL16, was found in the genome sequence of a clinical Acinetobacter baumannii ST25 isolate, D4. The variable part of KL16 contains a module of genes for synthesis of 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid, Pse5Ac7Ac), a gene encoding ItrA3 that initiates the CPS synthesis with d-GlcpNAc, and two glycosyltransferase (Gtr) genes. The K16 CPS was studied by sugar analysis and Smith degradation along with 1D and 2D H and C NMR spectroscopy, and shown to be built up of linear trisaccharide repeats containing d-galactose (d-Gal), N-acetyl-d-glucosamine (d-GlcNAc), and Pse5Ac7Ac.

Structure and gene cluster of the K125 capsular polysaccharide from Acinetobacter baumannii MAR13-1452.

A capsular polysaccharide (CPS) was isolated from strain MAR13-1452 of an emerging pathogen Acinetobacter baumannii and assigned type K125. The following structure of the CPS was established by sugar analysis, Smith degradation, and 1D and 2D H and C NMR spectroscopy: Proteins encoded by the KL125 gene cluster in the genome of MAR13-1452, including three glycosyltransferases, were assigned roles in the biosynthesis of the K125 CPS.

Novel Fri1-like Viruses Infecting Acinetobacter baumannii-vB_AbaP_AS11 and vB_AbaP_AS12-Characterization, Comparative Genomic Analysis, and Host-Recognition Strategy.

Acinetobacter baumannii is a gram-negative, non-fermenting aerobic bacterium which is often associated with hospital-acquired infections and known for its ability to develop resistance to antibiotics, form biofilms, and survive for long periods in hospital environments. In this study, we present two novel viruses, vB_AbaP_AS11 and vB_AbaP_AS12, specifically infecting and lysing distinct multidrug-resistant clinical A. baumannii strains with K19 and K27 capsular polysaccharide structures, respectively.

Complete genome sequence of novel T7-like virus vB_KpnP_KpV289 with lytic activity against Klebsiella pneumoniae.

A novel bacteriophage, vB_KpnP_KpV289, lytic for hypermucoviscous strains of Klebsiella pneumoniae, was attributed to the family Podoviridae, subfamily Autographivirinae, genus T7likevirus based on transmission electron microscopy and genome analysis. The complete genome of the bacteriophage vB_KpnP_KpV289 consists of a linear double-stranded DNA of 41,054 bp including 179-bp direct-repeat sequences at the ends and 51 open reading frames (ORFs). The G+C content is 52.

Atomic force microscopy analysis of the Acinetobacter baumannii bacteriophage AP22 lytic cycle.

Background: Acinetobacter baumannii is known for its ability to develop resistance to the major groups of antibiotics, form biofilms, and survive for long periods in hospital environments. The prevalence of infections caused by multidrug-resistant A. baumannii is a significant problem for the modern health care system, and application of lytic bacteriophages for controlling this pathogen may become a solution.

Molecular characterization of podoviral bacteriophages virulent for Clostridium perfringens and their comparison with members of the Picovirinae.

Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium responsible for human food-borne disease as well as non-food-borne human, animal and poultry diseases. Because bacteriophages or their gene products could be applied to control bacterial diseases in a species-specific manner, they are potential important alternatives to antibiotics. Consequently, poultry intestinal material, soil, sewage and poultry processing drainage water were screened for virulent bacteriophages that lysed C.

Isolation and characterization of wide host range lytic bacteriophage AP22 infecting Acinetobacter baumannii.

Acinetobacter baumannii plays a significant role in infecting patients admitted to hospitals. Many A. baumannii infections, including ventilation-associated pneumonia, wound, and bloodstream infections, are common for intensive care and burn units.