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Relative Contributions Of Enterococcus Faecalis Og1rf Sortase-Encoding Genes, Srta And Bps (Srtc), To Biofilm Formation And A Murine Model Of Urinary Tract Infection, Kelvin D Kemp, Kavindra V Singh, Sreedhar R Nallapareddy, Barbara E Murray

Journal Articles

Deletion mutants of the two sortase genes of Enterococcus faecalis OG1RF were constructed. srtC (renamed here bps for biofilm and pilus-associated sortase) was previously shown to be necessary for the production of Ebp pili and important for biofilm formation and endocarditis. Here, we report that a srtA deletion mutant showed a small (5%) yet significant (P = 0.037) reduction in biofilm relative to OG1RF, while a DeltasrtA Deltabps double mutant showed a much greater reduction (74% versus OG1RF and 44% versus the Deltabps mutant). In a murine urinary tract infection (UTI), the 50% infective doses of both the DeltasrtA Deltabps …

Ebpr Is Important For Biofilm Formation By Activating Expression Of The Endocarditis And Biofilm-Associated Pilus Operon (Ebpabc) Of Enterococcus Faecalis Og1rf, Agathe Bourgogne, Kavindra V Singh, Kristina A Fox, Kathryn J Pflughoeft, Barbara E Murray, Danielle A Garsin

Journal Articles

We identify ef1090 (renamed ebpR) and show its importance for the transcriptional regulation of expression of the Enterococcus faecalis pilus operon, ebpABC. An ebpR deletion (DeltaebpR) mutant was found to have reduced ebpABC expression with loss of pilus production and a defect in primary adherence with, as a consequence, reduced biofilm formation.

A Serratia Marcescens Oxyr Homolog Mediates Surface Attachment And Biofilm Formation, Robert M. Q. Shanks, Nicholas A. Stella, Eric J. Kalivoda, Megan R. Doe

Dartmouth Scholarship

OxyR is a conserved bacterial transcription factor with a regulatory role in oxidative stress response. From a genetic screen for genes that modulate biofilm formation in the opportunistic pathogen Serratia marcescens, mutations in an oxyR homolog and predicted fimbria structural genes were identified. S. marcescens oxyR mutants were severely impaired in biofilm formation, in contrast to the hyperbiofilm phenotype exhibited by oxyR mutants of Escherichia coli and Burkholderia pseudomallei. Further analysis revealed that OxyR plays a role in the primary attachment of cells to a surface. Similar to what is observed in other bacterial species, S. marcescens OxyR …

Importance Of The Ebp (Endocarditis- And Biofilm-Associated Pilus) Locus In The Pathogenesis Of Enterococcus Faecalis Ascending Urinary Tract Infection, Kavindra V Singh, Sreedhar R Nallapareddy, Barbara E Murray

Journal Articles

BACKGROUND: We recently demonstrated that the ubiquitous Enterococcus faecalis ebp (endocarditis- and biofilm-associated pilus) operon is important for biofilm formation and experimental endocarditis. Here, we assess its role in murine urinary tract infection (UTI) by use of wild-type E. faecalis OG1RF and its nonpiliated, ebpA allelic replacement mutant (TX5475).

METHODS: OG1RF and TX5475 were administered transurethrally either at an ~1 : 1 ratio (competition assay) or individually (monoinfection). Kidney pairs and urinary bladders were cultured 48 h after infection. These strains were also tested in a peritonitis model.

RESULTS: No differences were observed in the peritonitis model. In mixed UTIs, …

Inhibition Of Enterococcus Faecium Adherence To Collagen By Antibodies Against High-Affinity Binding Subdomains Of Acm, Sreedhar R Nallapareddy, Jouko Sillanpää, Vannakambadi K Ganesh, Magnus Höök, Barbara E Murray

Journal Articles

Strains of Enterococcus faecium express a cell wall-anchored protein, Acm, which mediates adherence to collagen. Here, we (i) identify the minimal and high-affinity binding subsegments of Acm and (ii) show that anti-Acm immunoglobulin Gs (IgGs) purified against these subsegments reduced E. faecium TX2535 strain collagen adherence up to 73 and 50%, respectively, significantly more than the total IgGs against the full-length Acm A domain (28%) (P < 0.0001). Blocking Acm adherence with functional subsegment-specific antibodies raises the possibility of their use as therapeutic or prophylactic agents.

Acquisition Of A Natural Resistance Gene Renders A Clinical Strain Of Methicillin-Resistant Staphylococcus Aureus Resistant To The Synthetic Antibiotic Linezolid, Seok-Ming Toh, Liqun Xiong, Cesar A Arias, Maria V Villegas, Karen Lolans, John Quinn, Alexander S Mankin

Journal Articles

Linezolid, which targets the ribosome, is a new synthetic antibiotic that is used for treatment of infections caused by Gram-positive pathogens. Clinical resistance to linezolid, so far, has been developing only slowly and has involved exclusively target site mutations. We have discovered that linezolid resistance in a methicillin-resistant Staphylococcus aureus hospital strain from Colombia is determined by the presence of the cfr gene whose product, Cfr methyltransferase, modifies adenosine at position 2503 in 23S rRNA in the large ribosomal subunit. The molecular model of the linezolid-ribosome complex reveals localization of A2503 within the drug binding site. The natural function of …

Agrobacterium Para/Mind-Like Virc1 Spatially Coordinates Early Conjugative Dna Transfer Reactions, Krishnamohan Atmakuri, Eric Cascales, Oliver T Burton, Lois M Banta, Peter J Christie

Journal Articles

Agrobacterium tumefaciens translocates T-DNA through a polar VirB/D4 type IV secretion (T4S) system. VirC1, a factor required for efficient T-DNA transfer, bears a deviant Walker A and other sequence motifs characteristic of ParA and MinD ATPases. Here, we show that VirC1 promotes conjugative T-DNA transfer by stimulating generation of multiple copies per cell of the T-DNA substrate (T-complex) through pairwise interactions with the processing factors VirD2 relaxase, VirC2, and VirD1. VirC1 also associates with the polar membrane and recruits T-complexes to cell poles, the site of VirB/D4 T4S machine assembly. VirC1 Walker A mutations abrogate T-complex generation and polar recruitment, …

Functional Taxonomy Of Bacterial Hyperstructures, Vic Norris, Tanneke Den Blaauwen, Armelle Cabin-Flaman, Roy H Doi, Rasika Harshey, Laurent Janniere, Alfonso Jimenez-Sanchez, Ding Jun Jin, Petra Anne Levin, Eugenia Mileykovskaya, Abraham Minsky, Milton Saier, Kirsten Skarstad

Journal Articles

The levels of organization that exist in bacteria extend from macromolecules to populations. Evidence that there is also a level of organization intermediate between the macromolecule and the bacterial cell is accumulating. This is the level of hyperstructures. Here, we review a variety of spatially extended structures, complexes, and assemblies that might be termed hyperstructures. These include ribosomal or "nucleolar" hyperstructures; transertion hyperstructures; putative phosphotransferase system and glycolytic hyperstructures; chemosignaling and flagellar hyperstructures; DNA repair hyperstructures; cytoskeletal hyperstructures based on EF-Tu, FtsZ, and MreB; and cell cycle hyperstructures responsible for DNA replication, sequestration of newly replicated origins, segregation, compaction, and …

Association Of Putative Enteroaggregative Escherichia Coli Virulence Genes And Biofilm Production In Isolates From Travelers To Developing Countries, Jamal A Mohamed, David B Huang, Zhi-Dong Jiang, Herbert L Dupont, James P Nataro, Jaime Belkind-Gerson, Pablo C Okhuysen

Journal Articles

Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhea among children, human immunodeficiency virus-infected patients, and travelers to developing regions of the world. The pathogenesis of EAEC strains involves the production of biofilm. In this study, we determined the association between presence of putative EAEC virulence genes and biofilm formation in 57 EAEC isolates (as defined by HEp-2 adherence) from travelers with diarrhea and in 18 EAEC isolates from travelers without diarrhea. Twelve nondiarrheagenic E. coli isolates from healthy travelers were used as controls. Biofilm formation was measured by using a microtiter plate assay …

Genome Sequence Of Fusobacterium Nucleatum Subspecies Polymorphum - A Genetically Tractable Fusobacterium, Sandor E Karpathy, Xiang Qin, Jason Gioia, Huaiyang Jiang, Yamei Liu, Joseph F Petrosino, Shailaja Yerrapragada, George E Fox, Susan Kinder Haake, George M Weinstock, Sarah K Highlander

Journal Articles

Fusobacterium nucleatum is a prominent member of the oral microbiota and is a common cause of human infection. F. nucleatum includes five subspecies: polymorphum, nucleatum, vincentii, fusiforme, and animalis. F. nucleatum subsp. polymorphum ATCC 10953 has been well characterized phenotypically and, in contrast to previously sequenced strains, is amenable to gene transfer. We sequenced and annotated the 2,429,698 bp genome of F. nucleatum subsp. polymorphum ATCC 10953. Plasmid pFN3 from the strain was also sequenced and analyzed. When compared to the other two available fusobacterial genomes (F. nucleatum subsp. nucleatum, and F. nucleatum subsp. vincentii) 627 open reading frames unique …