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1.
J Infect Dis ; 218(12): 1983-1994, 2018 11 05.
Article in English | MEDLINE | ID: mdl-30016475

ABSTRACT

Background: Bispecific antibody MEDI3902, targeting the Pseudomonas aeruginosa type 3 secretion system (PcrV) and Psl exopolysaccharide, is currently in phase 2b development for prevention of nosocomial pneumonia in patients undergoing mechanical ventilation. We surveyed a diverse collection of isolates to study MEDI3902 epitope conservation and protective activity. Methods: P. aeruginosa clinical isolates (n = 913) were collected from diverse patients and geographic locations during 2003-2014. We conducted whole-genome sequencing; performed PcrV and Psl expression analyses via immunoblotting and enzyme-linked immunosorbent assay, respectively; performed crystallography to determine the MEDI3902 PcrV epitope, using anti-PcrV Fab and PcrV components (resolved at 2.8 Å); and evaluated MEDI3902 protective activity against select isolates in vitro and in vivo. Results: Intact psl operon and pcrV genes were present in 94% and 99% of isolates, respectively, and 99.9% of isolates contained at least one of the genetic elements. Anti-Psl binding was confirmed in tested isolates harboring a complete Psl operon or lacking nonessential psl genes. We identified 46 PcrV variant sequences, and MEDI3902-PcrV contact residues were preserved. MEDI3902 maintained potent in vivo activity against various strains, including strains expressing only a single target. Conclusions: Psl and PcrV are highly prevalent in global clinical isolates, suggesting MEDI3902 can mediate broad coverage against P. aeruginosa.


Subject(s)
Antibodies, Bacterial/immunology , Antibodies, Monoclonal/immunology , Antigens, Bacterial/genetics , Bacterial Proteins/genetics , Conserved Sequence , Pseudomonas aeruginosa/metabolism , Antibodies, Bispecific , Antigens, Bacterial/immunology , Bacterial Proteins/immunology , Epitopes , Humans , Models, Molecular , Operon , Protein Conformation , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/immunology , Whole Genome Sequencing
2.
Mol Microbiol ; 41(2): 365-77, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11489124

ABSTRACT

The Staphylococcus aureus gene for toxic shock toxin (tst) is carried by a 15 kb mobile pathogenicity island, SaPI1, that has an intimate relationship with temperate staphylococcal phage 80alpha. During phage growth, SaPI1 is excised from its unique chromosomal site, attC, replicates autonomously, interferes with phage growth, and is efficiently encapsidated into special small phage heads commensurate with its size. Upon transfer to a recipient organism, SaPI1 integrates at attC by means of a self-coded integrase. One or more phage functions are required for excision, autonomous replication and encapsidation of the element and, thus, the overall relationship between SaPI1 and 80alpha is similar to that between coliphages P4 and P2. Among other staphylococcal phages tested, only phi13 interacts with SaPI1, inducing excision but not replication or transfer of the element.


Subject(s)
Bacterial Toxins , DNA Transposable Elements/genetics , Enterotoxins/genetics , Staphylococcus Phages/genetics , Staphylococcus aureus/genetics , Staphylococcus aureus/virology , Superantigens , Transduction, Genetic , Attachment Sites, Microbiological/genetics , DNA Replication , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Integrases/genetics , Integrases/metabolism , Microscopy, Electron , Models, Biological , Plasmids/genetics , Restriction Mapping , Staphylococcus Phages/growth & development , Staphylococcus Phages/ultrastructure , Staphylococcus aureus/pathogenicity , Virulence/genetics , Virus Assembly
3.
Microbes Infect ; 3(7): 585-94, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11418332

ABSTRACT

Variable genetic elements including plasmids, transposons and prophages are involved in pathogenesis and antibiotic resistance, and are an important component of the staphylococcal genome. This review covers a set of newly described variable chromosomal elements, pathogenicity and resistance islands, carrying superantigen and resistance genes, especially toxic shock and methicillin resistance, respectively.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Toxins , Staphylococcus/genetics , Base Sequence , Chromosomes, Bacterial/genetics , DNA, Bacterial/chemistry , Drug Resistance, Microbial/genetics , Enterotoxins/genetics , Enterotoxins/physiology , Evolution, Molecular , Genome, Bacterial , Humans , Methicillin Resistance/genetics , Microbial Sensitivity Tests , Molecular Sequence Data , Shock, Septic/microbiology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus/drug effects , Staphylococcus/immunology , Staphylococcus/pathogenicity , Superantigens/genetics , Superantigens/physiology
4.
J Bacteriol ; 182(9): 2668-71, 2000 May.
Article in English | MEDLINE | ID: mdl-10762277

ABSTRACT

Glycerol monolaurate (GML) inhibits the expression of virulence factors in Staphylococus aureus and the induction of vancomycin resistance in Enterococcus faecalis, presumably by blocking signal transduction. Although GML is rapidly hydrolyzed by bacteria, one of the products, lauric acid, has identical inhibitory activity and is metabolized much more slowly. At least four distinct GML-hydrolyzing activities are identified in S. aureus: the secreted Geh lipase, residual supernatant activity in a geh-null mutant strain, a novel membrane-bound esterase, and a cytoplasmic activity.


Subject(s)
Glycerides/metabolism , Laurates/metabolism , Lauric Acids/metabolism , Signal Transduction , Staphylococcus aureus/metabolism , Chromatography, Thin Layer/methods , Hydrolases/metabolism , Monoglycerides , Staphylococcus aureus/growth & development
5.
Mol Microbiol ; 29(2): 527-43, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9720870

ABSTRACT

Tst, the gene for toxic shock syndrome toxin-1 (TSST-1), is part of a 15.2 kb genetic element in Staphylococcus aureus that is absent in TSST-1-negative strains. The prototype, in RN4282, is flanked by a 17 nucleotide direct repeat and contains genes for a second possible superantigen toxin, a Dichelobacter nodosus VapE homologue and a putative integrase. It is readily transferred to a recA recipient, and it always inserts into a unique chromosomal copy of the 17 nucleotide sequence in the same orientation. It is excised and circularized by staphylococcal phages phi13 and 80alpha and replicates during the growth of the latter, which transduces it at very high frequency. Because of its site and orientation specificity and because it lacks other identifiable phage-like genes, we consider it to be a pathogenicity island (PI) rather than a transposon or a defective phage. The tst element in RN4282, near tyrB, is designated SaPI1. That in RN3984 in the trp region is only partially homologous to SaPI1 and is excised by phage 80 but not by 80alpha. It is designated SaPI2. These PIs are the first in any gram-positive species and the first for which mobility has been demonstrated. Their mobility may be responsible for the spread of TSST-1 production among S. aureus strains.


Subject(s)
Bacterial Toxins , DNA Transposable Elements , Enterotoxins/genetics , Staphylococcus Phages/genetics , Staphylococcus aureus/genetics , Staphylococcus aureus/pathogenicity , Superantigens , Amino Acid Sequence , Base Sequence , Genetic Variation , Molecular Sequence Data , Rec A Recombinases/genetics , Sequence Analysis, DNA , Sequence Deletion , Species Specificity , Transduction, Genetic
6.
J Bacteriol ; 180(1): 182-5, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9422612

ABSTRACT

Glycerol monolaurate (GML) is a surfactant that has been found to inhibit the post-exponential phase activation of virulence factor production and the induction of beta-lactamase in Staphylococcus aureus. It has been suggested that signal transduction is the most probable target for GML (S. J. Projan, S. Brown-Skrobot, P. M. Schlievert, F. Vandenesch, and R. P. Novick, J. Bacteriol. 176:4204-4209, 1994). We found that GML suppresses growth of vancomycin-resistant Enterococcus faecalis on plates with vancomycin and blocks the induction of vancomycin resistance, which involves a membrane-associated signal transduction mechanism, either at or before initiation of transcription. Given the surfactant nature of GML and the results of previous experiments, we suggest that GML blocks signal transduction. In contrast, GML has no effect on the induction of erythromycin-inducible macrolide resistance in S. aureus, which does not involve signal transduction.


Subject(s)
Anti-Bacterial Agents/pharmacology , Enterococcus faecalis/drug effects , Glycerides/pharmacology , Laurates/pharmacology , Surface-Active Agents/pharmacology , Vancomycin/pharmacology , Bacterial Proteins/genetics , Carbon-Oxygen Ligases/genetics , Drug Resistance, Microbial , Erythromycin/pharmacology , Methyltransferases/genetics , Microbial Sensitivity Tests , Monoglycerides , Mutation , Promoter Regions, Genetic/genetics , Signal Transduction/drug effects
7.
Bioorg Khim ; 21(11): 845-54, 1995 Nov.
Article in Russian | MEDLINE | ID: mdl-8670310

ABSTRACT

A number of recombinant plasmids for expression of artificial genes encoding human granulocyte-macrophage colony stimulating factor (GM-CSF) were constructed. A hybrid gene was obtained that contains a sequence encoding the leader peptide and a tandem of two IgG-binding domains of protein A from Staphylococcus aureus coupled, through an enteropepdidase linker, to a synthetic gmcsf gene. The construction enables Escherichia coli to carry out biosynthesis of the hybrid protein and its subsequent transport into the periplasmic space of bacteria. Another hybrid gene, combining sequences for the signal peptide of the E.coli outer membrane protein OmpA and GM-CSF, was obtained using polymerase chain reaction. The localization of the mature protein produced by the hybrid gene was found to depend on the strength of the promoter used.


Subject(s)
Escherichia coli/genetics , Genes, Synthetic , Granulocyte-Macrophage Colony-Stimulating Factor/genetics , Recombination, Genetic , Amino Acid Sequence , Bacterial Outer Membrane Proteins/genetics , Base Sequence , Cloning, Molecular , DNA, Recombinant , Humans , Molecular Sequence Data , Polymerase Chain Reaction , Recombinant Fusion Proteins/genetics , Staphylococcal Protein A/genetics
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