Results 1 - 10
of
20
Staphylococcus aureus capsular polysaccharides
- Clin. Microbiol. Rev
, 2004
"... Updated information and services can be found at: ..."
(Show Context)
2001. Influence of a functional sigB operon on the global regulators sar and agr in Staphylococcus aureus
- J
"... This article cites 56 articles, 37 of which can be accessed free ..."
Abstract
-
Cited by 53 (8 self)
- Add to MetaCart
(Show Context)
This article cites 56 articles, 37 of which can be accessed free
Staphylococcus aureus CcpA affects virulence determinant production and antibiotic resistance. Antimicrob. Agents Chemother. 50:1183–1194. Editor: V
- J. DiRita
, 2006
"... Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786)inStaphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determin ..."
Abstract
-
Cited by 36 (6 self)
- Add to MetaCart
(Show Context)
Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786)inStaphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the �ccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding �-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediateresistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a
2003. Molecular architecture of the regulatory locus sae of Staphylococcus aureus and its impact on expression of virulence factors
- J
"... Updated information and services can be found at: ..."
(Show Context)
Repression of the Staphylococcus aureus accessory gene regulator
, 2002
"... Updated information and services can be found at: ..."
(Show Context)
Corneal pathogenesis of Staphylococcus aureus strain Newman. Investigative Ophthalmology and Visual Science 43
, 2002
"... ..."
Effects of toxin production in a murine model of Staphylococcus aureus keratitis,”
- Investigative Ophthalmology and Visual Science,
, 2005
"... PURPOSE. To investigate the corneal virulence of toxin-deficient mutants of Staphylococcus aureus in young and aged mice in a topical inoculation model of keratitis. METHODS. Corneas of young and aged A/J mice were scarified and topically inoculated with a log phase S. aureus parent strain (8325-4) ..."
Abstract
-
Cited by 3 (1 self)
- Add to MetaCart
PURPOSE. To investigate the corneal virulence of toxin-deficient mutants of Staphylococcus aureus in young and aged mice in a topical inoculation model of keratitis. METHODS. Corneas of young and aged A/J mice were scarified and topically inoculated with a log phase S. aureus parent strain (8325-4), an ␣-toxin-deficient mutant (DU1090), or an Agr-defective mutant (ISP546) deficient in production of multiple toxins or with purified ␣-toxin. Slit lamp examination (SLE) and histopathology were performed, and bacterial colony-forming units (CFU) and myeloperoxidase (MPO) activity were determined. RESULTS. The infection of young mice with the mutant strains demonstrated significantly lower SLE scores (P Յ 0.0001) and reduced histopathologic changes compared with infections with the parent bacterial strain. Either mutant strain of S. aureus produced SLE scores in aged mice through 9 days after infection (PI) that were significantly lower than those of aged mice similarly infected with the toxin-producing parent strain (P Յ 0.0001). Despite use of identical inocula, the CFU per eye were greater for the parent than the mutant strains from 1 to 5 days PI in the young mice (P Յ 0.0372) and from 1 to 3 days PI in the aged mice (P Յ 0.0018). MPO activities were at the maximum at day 1 PI and were similar overall for all infections. Administration of purified ␣-toxin caused greater gross and histopathologic changes in eyes of aged mice than in those of young mice. CONCLUSIONS. Bacterial toxins, and especially ␣-toxin, can mediate corneal disease in mice. Differences in severity of S. aureus keratitis in aged versus young mice correlates with their susceptibility to ␣-toxin. (Invest Ophthalmol Vis Sci.
by Staphylococcus aureus
, 1996
"... Respiratory activity is essential for post-exponential-phase production of type 5 capsular polysaccharide by Staphylococcus aureus. ..."
Abstract
-
Cited by 1 (1 self)
- Add to MetaCart
(Show Context)
Respiratory activity is essential for post-exponential-phase production of type 5 capsular polysaccharide by Staphylococcus aureus.
� B and the � B-Dependent arlRS and yabJ-spoVG Loci Affect Capsule Formation in Staphylococcus aureus �
, 2007
"... The alternative transcription factor � B of Staphylococcus aureus affects the transcription of the cap gene cluster, required for the synthesis of capsular polysaccharide (CP), although this operon is lacking an apparent � B-dependent promoter. Regulation of cap expression and CP production in S. au ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
The alternative transcription factor � B of Staphylococcus aureus affects the transcription of the cap gene cluster, required for the synthesis of capsular polysaccharide (CP), although this operon is lacking an apparent � B-dependent promoter. Regulation of cap expression and CP production in S. aureus strain Newman was shown here to be influenced by � B, the two-component signal transduction regulatory system ArlRS, and the yabJ-spoVG locus to different extents. Inactivation of arlR or deletion of the sigB operon strongly suppressed capA (CP synthesis enzyme A) transcription. Deletion of spoVG had a polar effect on yabJ-spoVG transcription and resulted in a two- to threefold decrease in capA transcription. Interestingly, immunofluorescence showed that CP production was strongly impaired in all three mutants, signaling that the yabJ-spoVG inactivation, despite its only partial effect on capA transcription, abolished capsule formation. trans-Complementation of the �spoVG mutant with yabJ-spoVG under the control of its native promoter restored CP-5 production and capA expression to levels seen in the wild type. Northern analyses revealed a strong impact of � B on arlRS and yabJ-spoVG transcription. We hypothesize that ArlR and products of the yabJ-spoVG locus may serve as effectors that modulate � B control over � B-dependent genes lacking an apparent � B promoter. Staphylococcus aureus is a major nosocomial pathogen with the ability to cause a variety of diseases, including life-threatening
Capsular Polysaccharide by Human and Bovine Staphylococcus aureus Strains
, 1994
"... Two Staphylococcus aureus strains, the prototype human Reynolds strain and a bovine isolate, were grown in different complex media and in a synthetic medium (D. Taylor and K. T. Holland, J. Appl. Bacteriol. 66:319–329, 1989) and compared for their ability to produce type 5 capsular polysaccharide. C ..."
Abstract
- Add to MetaCart
(Show Context)
Two Staphylococcus aureus strains, the prototype human Reynolds strain and a bovine isolate, were grown in different complex media and in a synthetic medium (D. Taylor and K. T. Holland, J. Appl. Bacteriol. 66:319–329, 1989) and compared for their ability to produce type 5 capsular polysaccharide. Cell-bound and cell-free type 5 capsular polysaccharide were measured by a new one-step competition enzyme-linked immu-nosorbent assay. The total production and the proportion of cell-bound type 5 capsular polysaccharide were dependent on the nature of the medium, the duration of the culture, and the strain. Both strains produced more type 5 capsular polysaccharide when cultivated in the synthetic medium than when cultivated in complex media. The best yield of type 5 capsular polysaccharide, about 300 mg/ml of medium, was obtained with strain Reynolds grown for 48 h with shaking in the synthetic broth containing glucose as a carbon source. Capsular polysaccharides (CP) have been identified in clin-ical isolates of Staphylococcus aureus, and serological distinc-tion of 11 CP types has been proposed (19, 30). By using specific polyclonal or monoclonal antibodies, it has been shown that two CP types, 5 and 8 (CP5 and CP8), account for 70 to 80 % of S. aureus strains isolated from different human sites (4, 14, 30). Similar results have been obtained for isolates from cow, goat, and ewe milk (25) and for isolates from some other farm animals (27). Some evidence indicates that the production of capsular material is preferentially induced when S. aureus is grown in certain media. By use of the serum soft agar test, a conversion from compact to diffuse morphology has been observed when human and bovine isolates, grown on brain heart infusion (BHI) broth, were cultured on modified Staphylococcus me-
