Search

Staphylococcus saprophyticus, an important cause of urinary tract infections in young women, expresses the surface protein SdrI, a member of the serine-aspartate repeat (SD) protein family. Here we analyse the fibronectin-binding ability of SdrI, as S. saprophyticus is known to bind fibronectin and there is no known SD protein with this function. This protein does not contain the binding motif typical for fibronectin-binding proteins. Using recombinant fragments of SdrI, we localized the binding domain in the A region and show that SdrI bound to the N-terminal 30-kDa fragment of fibronectin. The fibronectin-binding function was shown in the natural host using an SdrI knockout mutant that showed decreased binding to fibronectin compared with wild-type strain 7108. [ABSTRACT FROM AUTHOR]

Human urine contains a relatively high concentration ofd-serine, which is toxic to several nonuropathogenic bacteria, but can be utilized or detoxified by uropathogenic Escherichia coli (UPEC). The sequenced genome of uropathogenic Staphylococcus saprophyticus contains a gene with homology to thed-serine deaminase gene ( dsdA) of UPEC. We found the gene in several clinical isolates of S. saprophyticus; however, the gene was absent in Staphylococcus xylosus and Staphylococcus cohnii, phylogenetically close relatives of S. saprophyticus, and could also not be detected in isolates of Staphylococcus aureus, Staphylococcus epidermidis and 13 other staphylococcal species. In addition, the genomes of other sequenced staphylococci do not harbor homologues of this operon. Interestingly, S. saprophyticus could grow in media supplemented with relatively high concentrations ofd-serine, whereas S. aureus, S. epidermidis and other staphylococcal species could not. The association of the dsdA gene with growth in media includingd-serine was proved by introducing the gene into S. aureus Newman. Given the fact that UPEC and S. saprophyticus tolerate this compound,d-serine utilization and detoxification may be a general property of uropathogenic bacteria. [ABSTRACT FROM AUTHOR]

Invasion of bacteria into nonphagocytic host cells is an important pathogenicity factor for escaping the host defence system. Gram-positive organisms, for example Staphylococcus aureus and Listeria monocytogenes, are invasive in nonphagocytic cells, and this mechanism is discussed as an important part of the infection process. Uropathogenic Escherichia coli and Staphylococcus saprophyticus can cause acute and recurrent urinary tract infections as well as bloodstream infections. Staphylococcus saprophyticus shows strong adhesion to human urinary bladder carcinoma and Hep2 cells and expresses the ‘Microbial Surface Components Recognizing Adhesive Matrix molecule’ (MSCRAMM)-protein SdrI with collagen-binding activity. MSCRAMMs are responsible for adhesion and collagen binding in S. aureus and are discussed as an important pathogenicity factor for invasion. To investigate internalization in S. aureus, several fluorescence activated cell sorting (FACS) assays have been described recently. We used a previously described FACS assay, with slight modifications, in addition to an antibiotic protection assay and transmission electron microscopy to show that S. saprophyticus ATCC 15305 and the wild-type strain 7108 were internalized into the human urinary bladder carcinoma cell line 5637. The discovery of the internalization of S. saprophyticus may be an important step for understanding the pathogenicity of recurrent infections caused by this organism. [ABSTRACT FROM AUTHOR]

Staphylococcus saprophyticus, an important cause of urinary tract infections, produces a surface-associated lipase, Ssp. In contrast to other lipases, Ssp is a protein that is present in high amounts on the surface of the bacteria and it was shown that it is a true lipase. Characterization of S. saprophyticus lipase (Ssp) showed that it is more similar to Staphylococcus aureus lipase and Staphylococcus epidermidis lipase than to Staphylococcus hyicus lipase and Staphylococcus simulans lipase. Ssp showed an optimum of lipolytic activity at pH 6 and lost its activity at pH>8 or pH<5. The present results show that Ssp activity is dependent on Ca2+. Consequently, activity increased c. 10-fold in the presence of 2 mM Ca2+. Optimal activity was reached at 30°C. It was also observed that the enzymatic activity of Ssp depends strongly on the acyl chain length of the substrate molecule. [ABSTRACT FROM AUTHOR]

An agr homologue of Staphylococcus saprophyticus was identified, cloned and sequenced. The gene locus shows homologies to other staphylococcal agr systems, especially to those of S. epidermidis and S. lugdunensis. A putative RNAIII was identified and found to be differentially expressed during the growth phases. In contrast to the RNAIII molecules of S. epidermidis and S. aureus it does not contain an open reading frame that codes for a protein with homologies to the δ-toxin. Using PCR, the agr was found to be present in clinical isolates of S. saprophyticus. [Copyright &y& Elsevier]

The Aas (autolysin/adhesin of Staphylococcus saprophyticus) is a multifunctional surface protein containing two enzymatic domains an N-acetyl-muramyl-L-alanine amidase, an endo-β-N-acetyl-D-glucosaminidase, and two different regions of repetitive sequences, an N-terminal and a C-terminal repetitive domain. The C-terminal repetitive domain is built up by the repeats R1, R2 and R3, which interconnect the putative active centers of the amidase and glucosaminidase. To investigate the influence of the C-terminal repeats and the N-terminal repeats on the amidase activity, the repetitive domains and fragments of them were cloned and expressed in Escherichia coli. The influence of the different fragments on the activity of the recombinant amidase of the Aas, consisting of the active center of the enzyme and repeat R1, was investigated in a turbidimetric microassay. The different fragments derived from the C-terminal repeats inhibited the amidase activity, while the N-terminal repeats did not influence the activity of the enzyme. The inhibiting activity increased with the number of GW repeats the recombinant fragment contained. Thus we conclude, that the C-terminal GW repeats and not the N-terminal repeats are necessary for the cell wall targeting and the autolytic function of the amidase. [Copyright &y& Elsevier]

Staphylococcus saprophyticus, an important cause of urinary tract infections in young women, expresses the surface protein SdrI, a member of the serine-aspartate repeat (SD) protein family. Here we analyse the fibronectin-binding ability of SdrI, as S. saprophyticus is known to bind fibronectin and there is no known SD protein with this function. This protein does not contain the binding motif typical for fibronectin-binding proteins. Using recombinant fragments of SdrI, we localized the binding domain in the A region and show that SdrI bound to the N-terminal 30-kDa fragment of fibronectin. The fibronectin-binding function was shown in the natural host using an SdrI knockout mutant that showed decreased binding to fibronectin compared with wild-type strain 7108.

Human urine contains a relatively high concentration of d-serine, which is toxic to several nonuropathogenic bacteria, but can be utilized or detoxified by uropathogenic Escherichia coli (UPEC). The sequenced genome of uropathogenic Staphylococcus saprophyticus contains a gene with homology to the d-serine deaminase gene (dsdA) of UPEC. We found the gene in several clinical isolates of S. saprophyticus; however, the gene was absent in Staphylococcus xylosus and Staphylococcus cohnii, phylogenetically close relatives of S. saprophyticus, and could also not be detected in isolates of Staphylococcus aureus, Staphylococcus epidermidis and 13 other staphylococcal species. In addition, the genomes of other sequenced staphylococci do not harbor homologues of this operon. Interestingly, S. saprophyticus could grow in media supplemented with relatively high concentrations of d-serine, whereas S. aureus, S. epidermidis and other staphylococcal species could not. The association of the dsdA gene with growth in media including d-serine was proved by introducing the gene into S. aureus Newman. Given the fact that UPEC and S. saprophyticus tolerate this compound, d-serine utilization and detoxification may be a general property of uropathogenic bacteria., (© 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Staphylococcus saprophyticus, an important cause of urinary tract infections, produces a surface-associated lipase, Ssp. In contrast to other lipases, Ssp is a protein that is present in high amounts on the surface of the bacteria and it was shown that it is a true lipase. Characterization of S. saprophyticus lipase (Ssp) showed that it is more similar to Staphylococcus aureus lipase and Staphylococcus epidermidis lipase than to Staphylococcus hyicus lipase and Staphylococcus simulans lipase. Ssp showed an optimum of lipolytic activity at pH 6 and lost its activity at pH>8 or pH<5. The present results show that Ssp activity is dependent on Ca(2+). Consequently, activity increased c. 10-fold in the presence of 2 mM Ca(2+). Optimal activity was reached at 30 degrees C. It was also observed that the enzymatic activity of Ssp depends strongly on the acyl chain length of the substrate molecule.