Publications (4)14.29 Total impact
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Article: A Collagen-Binding Adhesin, Acb, and Ten Other Putative MSCRAMM and Pilus Family Proteins of Streptococcus gallolyticus subsp. gallolyticus (Streptococcus bovis Group, Biotype I)▿ §
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ABSTRACT: Members of the Streptococcus bovis group are important causes of endocarditis. However, factors associated with their pathogenicity, such as adhesins, remain uncharacterized. We recently demonstrated that endocarditis-derived Streptococcus gallolyticus subsp. gallolyticus isolates frequently adhere to extracellular matrix (ECM) proteins. Here, we generated a draft genome sequence of an ECM protein-adherent S. gallolyticus subsp. gallolyticus strain and found, by genome-wide analyses, 11 predicted LPXTG-type cell wall-anchored proteins with characteristics of MSCRAMMs, including a modular architecture of domains predicted to adopt immunoglobulin (Ig)-like folding. A recombinant segment of one of these, Acb, showed high-affinity binding to immobilized collagen, and cell surface expression of Acb correlated with the presence of acb and collagen adherence of isolates. Three of the 11 proteins have similarities to major pilus subunits and are organized in separate clusters, each including a second Ig-fold-containing MSCRAMM and a class C sortase, suggesting that the sequenced strain encodes three distinct types of pili. Reverse transcription-PCR demonstrated that all three genes of one cluster, acb-sbs7-srtC1, are cotranscribed, consistent with pilus operons of other gram-positive bacteria. Further analysis detected expression of all 11 genes in cells grown to mid to late exponential growth phases. Wide distribution of 9 of the 11 genes was observed among S. gallolyticus subsp. gallolyticus isolates with fewer genes present in other S. bovis group species/subspecies. The high prevalence of genes encoding putative MSCRAMMs and pili, including a collagen-binding MSCRAMM, among S. gallolyticus subsp. gallolyticus isolates may play an important role in the predominance of this subspecies in S. bovis endocarditis.Journal of bacteriology 09/2009; · 3.94 Impact Factor -
Article: Adherence characteristics of endocarditis-derived Streptococcus gallolyticus ssp. gallolyticus (Streptococcus bovis biotype I) isolates to host extracellular matrix proteins.
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ABSTRACT: Members of the Streptococcus bovis group are frequent colonizers of the intestinal tract, which can also cause endocarditis. However, their ability to adhere to and colonize host tissues and the factors associated with pathogenicity are largely unknown. Here, we assessed 17 endocarditis-derived human isolates [identified here as 15 Streptococcus gallolyticus ssp. gallolyticus (S. bovis biotype I), one S. gallolyticus ssp. pasteurianus (biotype II/2) and one Streptococcus infantarius ssp. coli (biotype II/1)] for their in vitro adherence to components of the extracellular matrix (ECM). Adherence to collagen type I was found to be the most common phenotype exhibited by 76% of isolates, followed by collagen type IV (53%), fibrinogen (47%), collagen type V (35%) and fibronectin (35%). Pulsed-field gel electrophoresis analyses showed that >50% of endocarditis-derived S. gallolyticus ssp. gallolyticus isolates are genetically diverse, although two clusters of two and four isolates were observed. The diversity of strains and differences observed in adherence characteristics to distinct host ECM proteins suggest that isolates of S. gallolyticus ssp. gallolyticus produce different surface components, similar to other gram-positive pathogens, to colonize the host and cause infection.FEMS Microbiology Letters 01/2009; 289(1):104-9. · 2.04 Impact Factor -
Article: Reevaluation of Clinical and Laboratory Standards Institute disk diffusion breakpoints for tetracyclines for testing Enterobacteriaceae.
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ABSTRACT: We reevaluated Enterobacteriaceae disk diffusion breakpoints for the tetracyclines published in the Clinical and Laboratory Standards Institute (CLSI) document M100-S16, which were (susceptible/resistant) >or=19 mm/<or=14 mm for tetracycline, >or=16 mm/<or=12 mm for doxycycline, and >or=19 mm/<or=14 mm for minocycline. A collection of 504 recent clinical isolates of Enterobacteriaceae were tested against these tetracycline compounds by disk diffusion and broth microdilution methods according to CLSI guidelines. Regression line and scattergram plot analyses determined intermethod accuracy for current disk diffusion breakpoints and showed excellent r values of 0.91 to 0.95. However, error rates (minor/major [false-resistant]/very major [false-susceptible]) were 14.9/0.8/0.0% for tetracycline, 11.5/0.4/0.0% for doxycycline, and 30.6/0.7/0.0% for minocycline and only 4.4/0.0/0.0% for tetracycline, 5.6/0.0/0.2% for doxycycline, and 8.3/0.0/0.3% for minocycline when proposed breakpoints were modified to (susceptible/resistant) >or=15 mm/<or=11 mm for tetracycline, >or=14 mm/<or=10 mm for doxycycline, and >or=16 mm/<or=12 mm for minocycline. Listed modifications were recently approved by the CLSI (M100-S17).Journal of Clinical Microbiology 05/2007; 45(5):1640-3. · 4.15 Impact Factor -
Article: Identification of Streptococcus bovis biotype I strains among S. bovis clinical isolates by PCR.
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ABSTRACT: Streptococcus bovis causes 24% of all streptococcal infective endocarditis cases. There are many reports linking both S. bovis bacteremia and endocarditis with various forms of gastrointestinal disease (primarily colonic cancers). S. bovis is divided into two biotypes: I and II. The biotype I strain is much more frequently isolated from patients with endocarditis, gastrointestinal disease, or both. We describe here the isolation of biotype I-specific DNA sequences and the development of a PCR test which can identify S. bovis biotype I strains among S. bovis clinical isolates.Journal of Clinical Microbiology 09/2002; 40(8):2913-8. · 4.15 Impact Factor
