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PubMed1992

Influence of the pH-value on the growth of Staphylococcus epidermidis, Staphylococcus aureus and Propionibacterium acnes in continuous culture.

A cutaneous isolate of Staphylococcus epidermidis, Staphylococcus aureus and Propionibacterium acnes was grown in continuous culture at varying pH-values ranging from 5.0 to 8.5. In terms of the specific growth rate as well as the bacterial density during the plateau phase there were remarkable differences. In particular, Propionibacterium acnes grew much better in the pH 6.0 to 7.0 range than in a more acidic or alkaline milieu. Staphylococcus epidermidis resembled Staphylococcus aureus showing no major difference at pH 5.5 and 7.0. These findings substantiate the hypothesis that minor changes of the pH in the pH 5.5 to pH 6.0 range as to be induced by chemically neutral or alkaline skin cleansers on the human skin surface can increase the number of propionibacteria but not staphylococci remarkably due to the relative alkalinity by itself.

Culture Media↗
PubMed2006

Heterogeneous resistance to vancomycin in Staphylococcus epidermidis, Staphylococcus haemolyticus and Staphylococcus warneri clinical strains: characterisation of glycopeptide susceptibility profiles and cell wall thickening.

The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis, Staphylococcus haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values (P<0.01) compared with their respective parental strains. In general, variable rates of autolysis among the strains were observed. Cell wall thickness is an important factor involved in glycopeptide resistance and, in association with PAP results, confirmed the Brazilian coagulase-negative staphylococci clinical isolates as being heteroresistant to glycopeptides. Detection of these heteroresistant organisms is important in order to achieve more judicious use of vancomycin and teicoplanin in hospitals.

Anti-Bacterial Agents↗
PubMed1992

In vitro adherence of Staphylococcus saprophyticus, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus aureus to human ureter.

Staphylococcus saprophyticus adhered to human ureteral epithelium in vitro. The levels of adherence, which were determined quantitatively with the scanning electron microscope, correlated well with bacterial hemagglutinating activities with sheep erythrocytes (r = 0.9459, P < 0.01). Transmission electron microscopy revealed that the adhering bacteria and the hemagglutinating bacteria possessed similar pili-like structures on their cell surfaces. Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus aureus did not adhere to the epithelium. Only S. aureus adhered markedly to the connective tissue of the ureter, and adhesion of this organism was direct via its cell wall. This adherence test system clearly showed up differences in the abilities of these staphylococcal species to adhere to the urinary tract.

Bacterial Adhesion↗
PubMed1990

Presence of an additional penicillin-binding protein in methicillin-resistant Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, and Staphylococcus simulans with a low affinity for methicillin, cephalothin, and cefamandole.

The presence of an additional penicillin-binding protein (PBP) was demonstrated in methicillin-resistant strains of Staphylococcus epidermidis, S. haemolyticus, S. hominis, and S. simulans. In these four species, the apparent molecular mass of this protein was analogous to that of PBP 2' of methicillin-resistant S. aureus SR 1550-9. It exhibited a low affinity for methicillin, cephalothin, and cefamandole; and its synthesis was methicillin inducible. Peptide mapping of this PBP from the four species yielded identical results that were analogous to those obtained with S. aureus SR 1550-9. These results suggest that this protein is similar to, if not the same as, PBP 2' of S. aureus and that it is involved in methicillin resistance in the four species studied.

Bacterial Proteins↗
PubMed2006

Isolation of a strictly anaerobic strain of Staphylococcus epidermidis.

Staphylococcus epidermidis is a well-characterized, nonfastidious, aerobic gram-positive coccus commonly isolated in the clinical microbiology laboratory. Although coagulase-negative staphylococci, including Staphylococcus epidermidis, are often considered a contaminant in the clinical laboratory, an increasing number of reports describe their pathogenesis, in particular in infections of prosthetic devices. This article describes the isolation of a strictly anaerobic strain of Staphylococcus epidermidis in pure culture from the site of an infected prosthetic hip. This isolate was unique in that it grew only under strictly anaerobic conditions. Initially, the isolate was thought to be a known anaerobic gram-positive coccus. However, certain key biochemical and antimicrobial tests performed as part of the standard laboratory identification procedure were not consistent with results expected for any known anaerobic gram-positive coccus; the isolate was catalase positive and metronidazole and penicillin resistant. This isolate was characterized by further biochemical analysis, antimicrobial testing, and nucleic acid sequencing. This paper presents the first documented isolation of a strictly anaerobic Staphylococcus epidermidis strain, confirmed by rpoB gene sequencing.

Aged↗
PubMed2005

Identification and preliminary characterization of cell-wall-anchored proteins of Staphylococcus epidermidis.

Staphylococcus epidermidis is a ubiquitous human skin commensal that has emerged as a major cause of foreign-body infections. Eleven genes encoding putative cell-wall-anchored proteins were identified by computer analysis of the publicly available S. epidermidis unfinished genomic sequence. Four genes encode previously described proteins (Aap, Bhp, SdrF and SdrG), while the remaining seven have not been characterized. Analysis of primary sequences of the Staphylococcus epidermidis surface (Ses) proteins indicates that they have a structural organization similar to the previously described cell-wall-anchored proteins from S. aureus and other Gram-positive cocci. However, not all of the Ses proteins are direct homologues of the S. aureus proteins. Secondary and tertiary structure predictions suggest that most of the Ses proteins are composed of several contiguous subdomains, and that the majority of these predicted subdomains are folded into beta-rich structures. PCR analysis indicates that certain genes may be found more frequently in disease isolates compared to strains isolated from healthy skin. Patients recovering from S. epidermidis infections had higher antibody titres against some Ses proteins, implying that these proteins are expressed during human infection. Western blot analyses of early-logarithmic and late-stationary in vitro cultures suggest that different regulatory mechanisms control the expression of the Ses proteins.

Bacterial Proteins↗
PubMed1995

A simple and inexpensive method for the identification of Staphylococcus epidermidis and Staphylococcus hominis.

Eight hundred and ninety-two strains of Staphylococcus species were identified by means of desferrioxamine susceptibility and fermentation results of three carbohydrates, with the API Staph system (bioMérieux, France) as reference method. No identification could be obtained for 34 strains with API Staph. Of the remaining 858 strains, identical identification was obtained with 842 (98.1%). All 707 strains identified as Staphylococcus epidermidis or Staphylococcus hominis by the API Staph system were found to be desferrioxamine susceptible, and all but 5 (3.3%) of 151 strains identified as other staphylococcal species were found to be resistant, yielding an identification correlation of 99.4% for desferrioxamine. The five additional strains which were susceptible to desferrioxamine were identified as Staphylococcus capitis (2 strains), Staphylococcus lugdunensis (2 strains), and Staphylococcus warneri (1 strain) by API Staph, and as Staphylococcus epidermidis (1 strain), Staphylococcus hominis (3 strains), and one other staphylococcal species by the experimental system.

Deferoxamine↗
PubMed1998

Receptor-mediated recognition and uptake of iron from human transferrin by Staphylococcus aureus and Staphylococcus epidermidis.

Staphylococcus aureus and Staphylococcus epidermidis both recognize and bind the human iron-transporting glycoprotein, transferrin, via a 42-kDa cell surface protein receptor. In an iron-deficient medium, staphylococcal growth can be promoted by the addition of human diferric transferrin but not human apotransferrin. To determine whether the staphylococcal transferrin receptor is involved in the removal of iron from transferrin, we employed 6 M urea-polyacrylamide gel electrophoresis, which separates human transferrin into four forms (diferric, monoferric N-lobe, and monoferric C-lobe transferrin and apotransferrin). S. aureus and S. epidermidis but not Staphylococcus saprophyticus (which lacks the transferrin receptor) converted diferric human transferrin into its apotransferrin form within 30 min. During conversion, iron was removed sequentially from the N lobe and then from the C lobe. Metabolic poisons such as sodium azide and nigericin inhibited the release of iron from human transferrin, indicating that it is an energy-requiring process. To demonstrate that this process is receptor rather than siderophore mediated, we incubated (i) washed staphylococcal cells and (ii) the staphylococcal siderophore, staphyloferrin A, with porcine transferrin, a transferrin species which does not bind to the staphylococcal receptor. While staphyloferrin A removed iron from both human and porcine transferrins, neither S. aureus nor S. epidermidis cells could promote the release of iron from porcine transferrin. In competition binding assays, both native and recombinant N-lobe fragments of human transferrin as well as a naturally occurring human transferrin variant with a mutation in the C-lobe blocked binding of 125I-labelled transferrin. Furthermore, the staphylococci removed iron efficiently from the iron-loaded N-lobe fragment of human transferrin. These data demonstrate that the staphylococci efficiently remove iron from transferrin via a receptor-mediated process and provide evidence to suggest that there is a primary receptor recognition site on the N-lobe of human transferrin.

Animals↗
PubMed1990

Analysis of the relationship between bacterial adherence and extracellular production of mannose, galactose, glucose and ribose in Staphylococcus epidermidis and Staphylococcus hominis.

Gas-liquid chromatography-mass spectrometry was used to analyze the extracellular extracts of 108 coagulase-negative staphylococcal strains for the presence of mannose, galactose, glucose and ribose, in order to determine whether production of these four monosaccharides, regarded as potential staphylococcal slime components, was associated with the adherence capacity of the individuals strains. A total of 90 Staphylococcus epidermidis and 18 Staphylococcus hominis strains were studied. Using the quantitative spectrophotometric assay, 21 Staphylococcus epidermidis strains were classified as strongly adherent, 12 as moderately adherent, 11 as weakly adherent, and 46 as nonadherent. All 18 Staphylococcus hominis strains were nonadherent. Mannose, galactose, glucose and ribose were detected as the main monosaccharide components in the extracellular extracts of all strains examined. Moreover, the mean relative concentrations of these monosaccharides were essentially the same for the different adherence phenotypes within the species Staphylococcus epidermidis. These results showed that there was no causal connection between the adherence of coagulase-negative staphylococci and the extracellular production of any of the four monosaccharides analyzed.

Bacterial Adhesion↗
PubMed2002

Identification of a fibronectin-binding protein from Staphylococcus epidermidis.

Staphylococcus epidermidis has been reported to bind to a number of host cell extracellular matrix proteins, including fibronectin. Here we report the identification of a fibronectin-binding protein from S. epidermidis. A phage display library of S. epidermidis genomic DNA was constructed and panned against immobilized fibronectin. A number of phagemid clones containing overlapping inserts were identified, and one of these clones, pSE109FN, contained a 1.4-kb insert. Phage pSE109FN was found to bind to fibronectin but not to collagen, fibrinogen, laminin, or vitronectin. However, pSE109FN also bound to heparin, hyaluronate, and plasminogen, although to a lesser extent than it bound to fibronectin. Analysis of The Institute for Genomic Research S. epidermidis genome sequence database revealed a 1.85-kb region within a putative 30.5-kb open reading frame, to which the overlapping DNA inserts contained within the fibronectin-binding phagemids mapped. We have designated the gene encoding the fibronectin-binding domain embp. A recombinant protein, Embp32, which encompassed the fibronectin-binding domain of Embp, blocked the binding of S. epidermidis, but not the binding of Staphylococcus aureus, to fibronectin. In contrast, a recombinant protein, FnBPB[D1-D4], spanning the fibronectin-binding domain of the S. aureus fibronectin-binding protein FnBPB, blocked binding of S. aureus to fibronectin but had a negligible effect on the binding of S. epidermidis.

Adhesins, Bacterial↗
PubMed2005

Quantitative analysis of adhesion and biofilm formation on hydrophilic and hydrophobic surfaces of clinical isolates of Staphylococcus epidermidis.

Staphylococcus epidermidis is now well established as a major nosocomial pathogen associated with infections of indwelling medical devices. The major virulence factor of these organisms is their ability to adhere to devices and form biofilms. However, it has not been established that adherence and biofilm formation are closely linked phenotypes for clinical isolates. In this study, the initial adhesion to different materials (acrylic and glass) of 9 clinical isolates of S. epidermidis, along with biofilm-positive and biofilm-negative control strains, was assayed using physico-chemical interactions to analyze the basis for bacterial adherence to the substratum. X-ray photo electron spectroscopy (XPS) analysis of the cell surface elemental composition was also performed in an attempt to find a relationship between chemical composition and adhesion capabilities. Biofilm formation on the two surfaces was evaluated by dry weight measurements. Human erythrocytes were used to evaluate the ability of S. epidermidis strains to cause hemagglutination, an indicator of the production of a poly-N-acetyl glucosamine cell surface polysaccharide also involved in biofilm formation. The clinical isolates exhibited different cell wall physico-chemical properties, resulting in differing abilities to adhere to surfaces. Adhesion to hydrophobic substrata for all strains occurred to a greater extent than that to hydrophilic surfaces. Bacterial cell hydrophobicity seemed to have little or no influence on adhesion. X-ray photoelectron spectroscopy analysis showed a high ratio of oxygen/carbon for all strains, which is a common characteristic of S. epidermidis species. No relevant relationship was found between XPS data and adhesion values. All strains forming biofilms were able to agglutinate erythrocytes. However, no direct relationship was found between the amount of biofilm formed and the initial adhesion extent. These results indicate that high levels of initial adherence do not necessarily lead to thick biofilm formation. These two aspects of the pathogenesis of medical device related-infection may need to be evaluated independently to ascertain the contribution of each to the virulence of S. epidermidis causing device-related infections.

Acrylates↗
PubMed1993

Cervical adenitis caused by Staphylococcus epidermidis.

Staphylococcus epidermidis, a human commensal, is a common cause of bacteremia in immunocompromised patients with indwelling medical devices. We report a case of isolated cervical adenitis caused by S. epidermidis in an immunocompetent patient and comment on the presumed pathogenesis.

Anti-Bacterial Agents↗
PubMed1995

Septicemic shock from urinary tract infection caused by Staphylococcus epidermidis.

Staphylococcus epidermidis septicemia from a urinary source is rare. Two male patients had septicemic shock caused by S epidermidis urinary tract infection. Both patients had recently had indwelling urethral catheterization during severe illness. Bacteremia due to S epidermidis may be life-threatening. Although most cases of S epidermidis bacteremia are associated with infected intravascular devices, other portals of entry should be considered in a debilitated patient.

Aged↗
PubMed1996

[Methicillin-resistant Staphylococcus epidermidis].

Staphylococcus epidermidis has long been overlooked as a pathogen. Modern medicine gives this bacterium ample opportunities to display its pathogenic properties, notably as a colonizer of medical devices (catheters, implants), on which it grows, protected by an exopolysaccharide ('slime') layer. In addition, more and more methicillin-resistant strains are isolated. In Dutch intensive care units S. epidermidis is responsible for 20% of all infections, approximately one third of these isolates are methicillin resistant. As most people have S. epidermidis on their skin, spread and cross infection are unavoidable; still a judicious antibiotic use help to keep the frequency of resistance as low as possible.

Drug Resistance, Multiple↗
PubMed2003

Evaluation of a multilocus sequence typing system for Staphylococcus epidermidis.

Staphylococcus epidermidis is a significant cause of nosocomial disease. However, the taxonomy of this pathogen, particularly at subspecies level, is unclear. A multilocus sequence typing (MLST) scheme has therefore been investigated as a tool to elucidate taxonomic relationships within this group, based on genetic relatedness. DNA sequences for internal fragments of seven housekeeping genes were compared in 47 geographically and temporally diverse S. epidermidis isolates that were obtained from clinical infections. Twenty-three different allelic profiles were detected; 17 of these were represented by single strains and the largest profile group contained 17 isolates. Diversity of the same collection of isolates was investigated by using PFGE of SmaI-digested genomic DNA to test the discrimination and validity of the MLST approach. Isolates within the largest profile group were resolved into four distinct PFGE clusters on the basis of their SmaI digest patterns. Isolates within other profile groups that contained multiple isolates had matching PFGE SmaI patterns within each group. It appears that MLST is an effective method for grouping S. epidermidis strains at the subspecies level; however, it is not as discriminatory as it has been for other species for which MLST schemes have been established and, used alone, would not be a useful method for epidemiological studies. In addition, it was demonstrated that this method was effective for confirming the identity of S. epidermidis CoNS (coagulase-negative) isolates.

Bacterial Typing Techniques↗
PubMed2002

Environmental regulation of biofilm formation in intensive care unit isolates of Staphylococcus epidermidis.

Staphylococcus epidermidis is a common cause of prosthetic device-related infection in the intensive care unit (ICU). The environmentally regulated ica operon encodes a polysaccharide adhesin which is a key virulence determinant in the development of S. epidermidis biofilms. To evaluate the capacity of ICU S. epidermidis isolates to form biofilm, we measured biofilm production by 18 isolates associated with device-related infection and 20 contaminating isolates that were not associated with clinically diagnosed infection. Biofilm assays were performed in brain-heart infusion (BHI) medium and in BHI supplemented with salt, ethanol or subinhibitory tetracycline, all of which have the potential to promote biofilm formation. Polymerase chain reaction (PCR) was used to screen for the presence of the ica genes. A significant proportion of S. epidermidis strains associated with device-related infections (89%) were found to contain the ica locus compared with 50% of contaminating isolates (P = 0.01). However only four of 26 (15.3%) of all ica-positive isolates were biofilm-positive when grown in BHI medium, indicating that no significant association existed between the presence of the ica locus and biofilm-forming capacity, under standard growth conditions. In contrast the number of ica-positive isolates that were biofilm-positive under stress-inducing growth conditions or in the presence of subinhibitory tetracycline increased significantly to 73% (P = 0.02). These findings suggest that the presence of the ica locus alone is not sufficient for biofilm formation and that regulation of biofilm formation under altered growth conditions, which may exist in the in vivo environment, also plays a possible role in the pathogenesis of biomaterial-related S. epidermidis infections.

Biofilms↗
PubMed1998

Effect of subinhibitory concentrations of vancomycin, cefazolin, ofloxacin, L-ofloxacin and D-ofloxacin on adherence to intravascular catheters and biofilm formation by Staphylococcus epidermidis.

Staphylococcus epidermidis is the preeminent cause of nosocomial bacteraemia and infection of prosthetic medical devices. Bacterial adherence to biomaterial is a crucial early event in the pathogenesis of these infections. Antibiotics affect bacterial adherence to eukaryotic cells, capsule formation and biofilm production. However, results from studies involving coagulase-negative staphylococci are equivocal. In this study, the in-vitro adherence of radiolabelled bacteria was assayed to determine the effect of sublethal concentrations of a number of antibiotics on the attachment of four strains of S. epidermidis, with well-characterized adherence profiles, to intravascular catheters. The effect of antibiotics on biofilm production by S. epidermidis was assayed using a quantitative spectrophotometric assay. Although there was some strain-to-strain variability, none of the tested antibiotics affected bacterial attachment. However, treatment with cefazolin or vancomycin resulted in a significant decrease in biofilm elaboration. These data suggest that bacterial attachment by S. epidermidis, the initiating event associated with prosthetic device infection, cannot be prevented by subtherapeutic levels of fluoroquinolone, glycopeptide or beta-lactam antibiotics. However, later aggregative stages of adherence, associated with biofilm production, may be influenced by cell wall-active agents such as cefazolin and vancomycin.

Bacterial Adhesion↗
PubMedDate not supplied

Staphylococcosis of turkeys. 6. Development of penicillin resistance in an interfering strain of Staphylococcus epidermidis.

Staphylococcus epidermidis strain 115, used as an interfering agent to help reduce the incidence of staphylococcosis in turkeys, was converted into a penicillin- and chloramphenicol-resistant strain designated 115R. This was accomplished by introducing a plasmid carrying the beta-lactamase (penicillinase) and chloramphenicol-resistance genes into S. epidermidis 115 by electroporation. The resultant strain, 115R, was an efficient producer of beta-lactamase and had marked increased resistance to penicillin and chloramphenicol. A beta-lactamase DNA probe was used to confirm the presence of the beta-lactamase gene in strain 115R. S. epidermidis strain 115R retained the characteristics of tissue adherence, bacteriocin production, and non-virulence that were present in the original non-transformed strain 115, and in addition should theoretically remain colonized in poults following treatment with penicillin.

Animals↗