PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Staphylococcus epidermidis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1992

Genetic analysis of epidermin biosynthetic genes and epidermin-negative mutants of Staphylococcus epidermidis.

Epidermin is produced by Staphylococcus epidermidis Tü3298 which harbors the 54-kb plasmid, pTü32. The plasmid contains not only the epidermin structural gene epiA, but also a flanking DNA region which is necessary for epidermin biosynthesis. The DNA sequence of this region revealed, in addition to epiA, five additional open reading frames, epiB, C, D, Q and P [Schnell, N., Engelke, G., Augustin J., Rosenstein, R., Ungermann, V., Götz, F. & Entian, K.-D. (1992) Eur. J. Biochem. 204, 57-68]. We isolated a number of stable mutants from strain Tü3298 which are unable to produce biologically active epidermin. Complementation studies using the newly constructed staphylococcal plasmid vectors pT181mcs and pCU1 led to their classification as epiA, epiB, epiC or epiD mutants. Furthermore, evidence is presented that epiB lacks its own promoter and is co-transcribed from the epiA promoter. There is evidence that epiC and D possess their own promoters. Although epiQ and epiP mutants were not isolated, it could be shown by heterologous gene expression in S. carnosus and S. xylosus that the corresponding DNA region is involved in epidermin biosynthesis. We can not exclude the possibility that, in addition to the four open reading frames, epiA, B, C, D, and the DNA region comprising epiQ and P, host-encoded functions are necessary for epidermin production. Thus, the genetic information for epidermin biosynthesis in S. carnosus and S. xylosus is located on an 8-kb DNA fragment of pTü32. A further characterization of the two epiA mutants revealed that in both mutants, the preepidermin nucleotide sequence was changed. In one mutant, the mutation led to a substitution of Ser3 by Asn; in the other of Gly10 by Glu.

Amino Acid Sequence↗
PubMed2006

Conserved genes in a path from commensalism to pathogenicity: comparative phylogenetic profiles of Staphylococcus epidermidis RP62A and ATCC12228.

BACKGROUND: Staphylococcus epidermidis, long regarded as an innocuous commensal bacterium of the human skin, is the most frequent cause of nosocomial infections associated with implanted medical devices. This conditional pathogen provides a model of choice to study genome landmarks correlated with the transition between commensalism and pathogenicity. Traditional investigations stress differences in gene content. We focused on conserved genes that have accumulated small mutation differences during the transition. RESULTS: A comparison of strain ATCC12228, a non-biofilm forming, non-infection associated strain and strain RP62A, a methicillin-resistant biofilm clinical isolate, revealed consistent variation, mostly single-nucleotide polymorphisms (SNPs), in orthologous genes in addition to the previously investigated global changes in gene clusters. This polymorphism, scattered throughout the genome, may reveal genes that contribute to adaptation of the bacteria to different environmental stimuli, allowing them to shift from commensalism to pathogenicity. SNPs were detected in 931 pairs of orthologs with identical gene length, accounting for approximately 45% of the total pairs of orthologs. Assuming that non-synonymous mutations would mark recent evolution, and hence be associated to the onset of the pathogenic process, analysis of ratios of non-synonymous SNPs vs synonymous SNPs suggested hypotheses about possible pathogenicity determinants. The N/S ratios for virulence factors and surface proteins differed significantly from that of average SNPs. Of those gene pairs, 40 showed a disproportionate distribution of dN vs dS. Among those, the presence of the gene encoding methionine sulfoxide reductase suggested a possible involvement of reactive oxygen species. This led us to uncover that the infection associated strain was significantly more resistant to hydrogen peroxide and paraquat than the environmental strain. Some 16 genes of the list were of unknown function. We could suggest however that they were likely to belong to surface proteins or considered in priority as important for pathogenicity. CONCLUSION: Our study proposed a novel approach to identify genes involved in pathogenic processes and provided some insight about the molecular mechanisms leading a commensal inhabitant to become an invasive pathogen.

Bacterial Proteins↗
PubMed1994

Identification of coagulase-negative staphylococci and typing of Staphylococcus epidermidis by a 4 h micromethod.

A new 4 h micromethod (Minibact-S) for identification of coagulase-negative staphylococci (CNS) important in human medicine, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus haemolyticus and Staphylococcus saprophyticus, has been investigated. The reproducibility for species identification was 100% and the reproducibility for the single reactions was 95%. When compared to a modified Kloos & Schleifer conventional identification method, discrepant identification was obtained with the Minibact-S in only 8 of 382 clinical and reference strains. The system has been used for typing and biotyping of 201 S. epidermidis strains, and gave a subdivision in 69 different types; 4 related types accounted for 91 (45%) of the isolates, whereas 44 types were represented by only 1 isolate. The discriminatory index was 0.82. In a comparison with other typing methods performed on 81 isolates from 15 patients Minibact-S gave about the same number of types as antibiograms, but in 20% of the patients extra types were obtained with Minibact-S alone compared to antibiogram alone and vice versa. The Minibact-S is of some value in the routine clinical microbiology laboratory as a first screening method for identification of coagulase-negative staphylococci and typing of S. epidermidis in combination with the antibiogram.

Coagulase↗
PubMed1989

Surface free energy and interaction of Staphylococcus epidermidis with biomaterials.

The adhesion of twenty nine Staphylococcus epidermidis strains to teflon, polyethylene, polycarbonate and bovine pericardium was studied in vitro and examined in relation to the surface free energies of both bacteria and biomaterials. All S. epidermidis strains had similar surface free energies, close to that of water, and adhered better to the materials with analogous surface free energies. There was a significant correlation (Kendall's Tau B = 1000) of biomaterial's surface free energy with the number of adhering bacteria. This correlation is inverse (Kendall's Tau B = -1000) when surface hydrophobicity is considered instead of surface free energy. This indicates that in Staphylococcus epidermidis adherence to biomaterials is inversely correlated to the surface hydrophobicity of the last, being so just the opposite of that occurring with other bacteria.

Bacterial Adhesion↗
PubMed1993

Characterization of an extracellular metalloprotease with elastase activity from Staphylococcus epidermidis.

The gene sepA from Staphylococcus epidermidis TU3298-P, encoding the extracellular neutral metalloprotease SepP1, was cloned into pT181mcs. DNA sequencing revealed an open reading frame of 1,521 nucleotides encoding a 507-amino-acid protein with an M(r) of 55,819. The sepA-containing DNA fragment did not hybridize with Staphylococcus hyicus or Staphylococcus carnosus DNA. Expression of sepA in the protease-negative S. carnosus (pT181mcsP1) resulted in overproduction of a 33-kDa protease found in the culture medium. The first 15 N-terminal amino acids of the partially purified protease completely matched the deduced DNA sequence starting at GCA (Ala-208). This finding indicated that SepP1 is synthesized as a preproenzyme with a 28-amino-acid signal peptide, a 179-amino-acid hydrophilic pro region, and a 300-amino-acid extracellular mature form with a calculated M(r) of 32,739. In activity staining, the mature protease prepared from S. carnosus (pT181mcsP1) corresponded to the extracellular S. epidermidis Tü3298-P protease. The partially purified protease had a pH optimum between 5 and 7, and its activity could be inhibited by zinc- and metal-specific inhibitors such as EDTA and 1,10-phenanthroline, indicating that it is a neutral metalloprotease. The protease had a low substrate specificity. Glucagon was cleaved preferentially between aromatic (Phe) and hydrophobic (Val) amino acids. The protease hydrolyzed casein and elastin. The amino acid sequence of the mature form of SepP1 revealed pronounced similarities with the thermolabile and thermostable neutral proteases of various bacilli (44 to 55% identity) and a central part of the mature form of the Pseudomonas aeruginosa elastase (31% identity). From homology comparison with the Bacillus thermoproteolyticus thermolysin, we predict that mature SepP1 binds one zinc ion at a conserved zinc-binding site.

Amino Acid Sequence↗
PubMed1985

Comparative in vitro inhibitory and killing activity of cefpirome, ceftazidime, and cefotaxime against Pseudomonas aeruginosa, enterococci, Staphylococcus epidermidis, and methicillin-susceptible and -resistant and tolerant and nontolerant Staphylococcus aureus.

With a macrotube dilution method, MICs and MBCs were determined for three aminothiazolyl cephalosporins, cefpirome (HR 810), ceftazidime, and cefotaxime, against Pseudomonas aeruginosa, enterococci, Staphylococcus epidermidis, and methicillin-resistant, -susceptible, and -tolerant strains of Staphylococcus aureus. Comparatively, cefpirome was the most active agent against all gram-positive cocci, including enterococci and methicillin-resistant S. aureus, and was as active as ceftazidime against P. aeruginosa. MBCs of cefpirome were within two dilutions of the MICs for 91% of P. aeruginosa and 90% of gram-positive cocci strains tested, except methicillin-resistant S. aureus, for which the MBCs were within three dilutions for 90% of strains.

Bacteria↗
PubMed1995

Necrotizing fasciitis: the role of Staphylococcus epidermidis, immune status and intravascular coagulation.

An 83 year old Caucasian woman with necrotizing fasciitis (NF) of the right hand is described. Staphylococcus epidermidis was the only organism cultured. Serology failed to demonstrate Streptococcus pyogenes, the common pathogen of NF. Despite antibiotic therapy, gangrene supervened, necessitating digital amputation. Staphylococcus epidermidis is usually non-pathogenic, but review of the literature indicates that it is relatively commonly found with other pathogens in NF. Accordingly, studies of immune status were undertaken. Apart from reduced myeloperoxidase production (30-50% of normal levels), all humoral, cell-mediated and neutrophil function tests were normal. This is the first report of Staphylococcus epidermidis as the sole isolate in NF and also the only study of immune status of NF patients. It is concluded that a non-virulent organism (e.g. Staphylococcus epidermidis) may be pathogenic in the face of advanced age alone. Elevated fibrin degradation productions were also demonstrated in the patient, consistent with lysis of localized intravascular thrombus. The role of anticoagulation in NF is discussed.

Aged↗
PubMed1992

Comparative evaluation of a new molecular method for typing Staphylococcus epidermidis.

The discriminatory powers of several techniques for typing Staphylococcus epidermidis were evaluated in an epidemiological study of bacteria isolated from intensive care patients and from neonates. Genomic DNA fingerprinting using BclI restriction endonuclease was an effective epidemiological marker. The distinct restriction fragment profiles produced with this enzyme were highlighted with specific probes in a Southern blot technique. Cloned Escherichia coli rRNA gene probes proved to have lower discriminatory power and be less suitable for intraspecies typing. However, a panel of random genomic Staphylococcus epidermidis DNA clones provided almost the same level of discrimination as the DNA fingerprinting technique and also provided a clearer profile. DNA and gene fingerprinting techniques were reproducible and highly discriminatory compared to typing based on antigen and plasmid profiles, antibiotic susceptibility patterns and biotypes.

Blotting, Southern↗
PubMed2002

Staphylococcus epidermidis infections.

The opportunistic human pathogen Staphylococcus epidermidis has become the most important cause of nosocomial infections in recent years. Its pathogenicity is mainly due to the ability to form biofilms on indwelling medical devices. In a biofilm, S. epidermidis is protected against attacks from the immune system and against antibiotic treatment, making S. epidermidis infections difficult to eradicate.

Bacterial Adhesion↗
PubMed1994

Differential inhibition by clindamycin on slime formation, adherence to teflon catheters and hemolysin production by Staphylococcus epidermidis.

Slime formation was detected in Staphylococcus epidermidis strains isolated from either infected patients or healthy individuals. Cells of S. epidermidis, that either formed slime or not, adhered to teflon catheters. There was no correlation between adherence of bacteria to teflon catheters and slime formation. Clindamycin at subinhibitory concentration significantly inhibited slime formation without inhibiting bacterial growth. Adherence of S. epidermidis to teflon catheters was affected by the presence of clindamycin whether slime was produced or not. Clindamycin at subinhibitory concentrations markedly inhibited hemolysin production by S. epidermidis without appreciably altering the cell density, and cells grown in the presence of the drug showed very low hemolytic activity upon disruption. These results suggest that clindamycin at low concentration alters S. epidermidis virulence properties, apart from inhibiting growth.

Bacterial Adhesion↗
PubMed1992

Plasmid-pattern analysis in the differentiation of Staphylococcus epidermidis isolates.

Plasmids carried by 29 Staphylococcus epidermidis isolates from two different origins (invasive and carrier, non-hospital-associated strains) were analysed by agarose gel electrophoresis in order to evaluate any association with virulence. Plasmid patterns were found to be characteristic of individual strains and no particular molecular size band was found to correlate with either of the two categories of isolates. It is concluded that the plasmid pattern analysis carried out could not differentiate between carrier and invasive S. epidermidis, but did provide a useful tool for epidemiological investigation.

Electrophoresis, Agar Gel↗
PubMed1995

Identity of macromolecules present in the extracellular slime layer of Staphylococcus epidermidis.

The extracellular slime layer of Staphylococcus epidermidis ATCC 35983 contains: a) two non-anionic carbohydrate containing proteins degradable with papain of molecular masses 250 and 125 kDa; b) a polydisperse but homogeneously-charged acidic population with M(r) ranging from 120,000 to 35,000 (average M(r) (80,000) containing a polysaccharide covalently bound to a small peptide; c) a papain degradable macromolecule (molecular mass 60 kDa) bearing acidic carbohydrates covalently bound to protein; and c) two acidic polysaccharides strongly retained by the anion-exchange column; one polysaccharide is sulphated and has a molecular mass of 20 kDa; the other has a higher charge density and a molecular mass of 12.5 kDa. The results obtained clearly demonstrate the presence of discrete macromolecules in the extracellular material of slime-producing S epidermidis, the majority of which contain acidic carbohydrates, whose biological role remains to be elucidated.

Chemical Fractionation↗
PubMed2004

Genetic and phenotypic analysis of biofilm phenotypic variation in multiple Staphylococcus epidermidis isolates.

Production of biofilm in Staphylococcus epidermidis is mediated through enzymes produced by the four-gene operon ica and is subject to phenotypic variation. The purpose of these experiments was to investigate the regulation of ica and icaR transcription in phenotypic variants produced by multiple unrelated isolates of S. epidermidis. Ten isolates were chosen for the study, four of which contained IS256. IS256 mediates a reversible inactivation of ica in approximately 30 % of phenotypic variants. All ten strains produced at least two types of phenotypic variant (intermediate and smooth) in which biofilm formation was significantly impaired. Reversion studies indicated that all phenotypic variants were stable after overnight growth, but began to revert to other phenotypic forms after 5 days of incubation at 37 degrees C. ica transcriptional analysis was performed on phenotypic variants from three IS256-negative isolates; 1457, SE5 and 14765. This analysis demonstrated that ica transcription was significantly reduced in the majority of phenotypic variants, although two variants from SE5 and 1457 produced wild-type quantities of ica transcript. Analysis of seven additional phenotypic variants from SE5 revealed that ica expression was only reduced in three. Expression of icaR transcript was unaffected in all smooth phenotypic variants. Mutations within ica were identified in two SE5 variants with wild-type levels of ica transcription. It is concluded that mutation and transcriptional regulation of ica are the primary mechanisms that govern phenotypic variation of biofilm formation within IS256-negative S. epidermidis.

Bacterial Proteins↗
PubMed1986

Factors affecting Staphylococcus epidermidis growth in peritoneal dialysis solutions.

Staphylococcus epidermidis is the most frequent cause of peritonitis complicating continuous ambulatory peritoneal dialysis. We studied factors that might influence the growth of S. epidermidis in commercially available peritoneal dialysis solution (PDS). Test strains were inoculated into PDS and incubated overnight at 37 degrees C. Samples were removed at appropriate intervals, bacterial counts were performed, and growth curves were constructed. We studied the effects of various osmolarities, the neutralization and acidification of fresh and spent PDS, and the effect of intraperitoneal dwell time on the ability PDS to support growth of S. epidermidis. In fresh PDS, numbers of bacteria remained constant after 24 h. No significant differences in growth were observed among PDS with 0.5, 1.5, 2.5, and 4.25% glucose. Neutralizing acidic fresh PDS had no effect on bacterial growth. However, growth did occur in spent PDS. PDS which was recovered after only 2 h in the peritoneal cavity supported growth to the same extent as did PDS recovered after 4 to 6 h. Mean log10 changes after 24 h of incubation were as follows: for fresh PDS, -1.3; after 2 h dwell time, 2.9; after 4 h dwell time, 1.9; and after 6 h dwell time, 1.3. Acidification of spent PDS to less than pH 6.35 produced less rapid growth; mean log10 increases after 24 h of incubation were 1.9 for pH 7.75, 1.6 for pH 6.35, 0.6 for pH 5.75, and 0.7 for pH 4.95. Fresh PDS of all available osmolarities neither supported the growth of S. epidermidis nor was bactericidal. Spent PDS supported bacterial growth, and this growth was partly independent of the neutralization which occurred during the dialysis.

Amino Acids↗
PubMed1991

Foreign-body-associated experimental osteomyelitis induced with Bacteroides fragilis and Staphylococcus epidermidis in rabbits.

Bacteroides fragilis and Staphylococcus epidermidis, alone and in combination, were used to induce foreign-body-associated osteomyelitis in a rabbit model. In this model, a catheter, used as a foreign body, was implanted into the medullary cavity of the tibia. Only two of five animals infected with S. epidermidis alone developed culture-positive osteomyelitis, whereas all three animals infected with B. fragilis alone developed osteomyelitis. All six animals infected with both microorganisms developed culture-positive osteomyelitis. Roentgenographic and histologic evaluations confirmed the diagnosis of osteomyelitis. Transmission and scanning electron microscopy showed that when the two microorganisms are involved in a mixed infection, S. epidermidis predominates on the foreign body and B. fragilis predominates in the infected bone and marrow.

Animals↗
PubMed1996

Factors affecting Staphylococcus epidermidis adhesion to contact lenses.

BACKGROUND: Staphylococcus epidermidis is a major causative agent of infectious keratitis associated with contact lens wear. Adhesion of this bacterium to contact lenses may contribute to the pathogenesis of infection and could be influenced by lens surface properties, packaging/storage solutions, and vary among different strains according to the level or type of adhesins expressed. METHODS: Adhesion of six clinical isolates of S. epidermidis to three different contact lens materials was tested. Adhesion assays were performed on lenses immediately after removal from their packages, and also after lenses were soaked in sterile phosphate buffered saline (PBS) for 7 days to dilute the packaging solution. RESULTS: For lenses tested immediately upon removal from their packaging, adhesion to polymacon (in PBS with 0.1% polyvinyl alcohol) was significantly greater than to etafilcon A (in borate buffered saline) and vifilcon A (in PBS). After soaking, adhesion to polymacon lenses was significantly less than to the other lens materials. This pattern was consistent for all strains, although major differences in baseline adhesion levels existed between strains, with exopolysaccharide (slime)-positive bacteria being more adherent to lenses. CONCLUSIONS: Properties of contact lens materials were not the sole determinant of viable S. epidermidis adhesion to lenses. Strain variability, including levels of exopolysaccharide expression, and the solution used for lens immersion also influenced adhesion.

Bacterial Adhesion↗
PubMed2001

Interaction of Staphylococcus epidermidis with endothelial cells in vitro.

Staphylococcus epidermidis is a leading cause of nosocomial bacteremia, yet virtually nothing is known about how this pathogen interacts with human endothelial cells. We present evidence here that two biofilm-producing strains of S. epidermidis adhere to two types of endothelial cell lines in vitro and that adherence is significantly increased after briefly heat-treating the bacteria at 40 degrees C in the presence of calcium. This mild heat treatment resulted in bacteria that were 5 to more than 20 times more adherent than untreated controls. While the adherence of bacteria in all phases of growth was increased after heat treatment, heat-treated late stationary phase cells were generally the most adherent. Electron microscopy demonstrated that S. epidermidis was internalized and appeared to exist free in the cytoplasm. Adherence to endothelium, should it occur in vivo during bacteremia, may be a virulence factor associated with this bacterium's pathogenesis.

Bacterial Adhesion↗