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PubMed1998

Slime production of Staphylococcus epidermidis: increased bacterial adherence and accumulation onto pure titanium.

In an in vitro study using Staphylococcus epidermidis RP 62 A, a slime-producing strain and its isogenic slime-negative mutant M7, we demonstrated that both strains adhere to pure titanium discs with significantly higher colony counts for the slime-producing strain. The colony count was dependent on temperature, time and strain. Prolonged incubation time (24 h) under growth conditions leads to higher colony counts for the slime-producing strain RP 62 A. As the slime-negative mutant M7 can adhere to, but not form multiple layers on metallic surfaces, increase of incubation time does not produce higher colony counts on the metallic surface. We conclude that slime production is important for adherence and subsequent accumulation of S. epidermidis onto pure titanium discs in vitro.

Analysis of Variance↗

PubMed2002

Methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis infections in the cornea.

PURPOSE: To describe the incidence and clinical management of corneal infections with methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant Staphylococcus epidermidis (MRSE). METHODS: The incidence of methicillin-resistant Staphylococcus (MRS) at the Department of Ophthalmology, Kyoto Prefectural University of Medicine, was reviewed during the 5-year period from January 1996 to December 2000. Clinical aspects of MRS colonization or infection in the eye were investigated. RESULTS: Methicillin-resistant S. aureus or MRSE was detected from 30 eyes with ocular diseases; post-keratoplasty (11 eyes), ocular surface disorders without operation (9 eyes), and others (10 eyes). Among the 30 eyes, 12 manifested keratitis. Eight cases (8 eyes) occurred after keratoplasty, including four postoperative cases in patients with Stevens-Johnson syndrome, and two bilateral cases (4 eyes) in patients with acute-phase Stevens-Johnson syndrome. The degree of MRS keratitis was classified into 4 groups: asymptomatic carrier or conjunctivitis, intraepithelial infiltrations, superficial keratitis, and severe keratitis leading to corneal perforation. All cases of keratitis were treated successfully with topical ofloxacin (OFLX), vancomycin (VCM), or arbekacin (ABK). CONCLUSION: Factors associated with ocular MRS colonization were long-term use of antibiotics and/or steroids, and hospitalization. Patients who had undergone keratoplasty or who had Stevens-Johnson syndrome were at increased risk of MRS keratitis. Superficial stromal infiltrations, minimal melting, and minimal stromal scarring are characteristic of MRS keratitis. Therapy for MRS keratitis is summarized. Ofloxacin, VCM, and ABK are effective in the treatment of MRS keratitis. Vancomycin eye ointment is effective as the final choice in serious cases.

Adult↗

PubMed2000

[Epidemiological study on Staphylococcus epidermidis isolated from bloodstream and blood vessel catheter].

An epidemiological study on 35 strains of Staphylococcus epidermidis was conducted in Juntendo University Hospital between 1994 and 1996. The strains were isolated from blood and blood vessel catheters. Three epidemiological markers; PFGE type (pulsed-field gel electrophoresis using SmaI), biotype by STAPHYOGRAM and antibiotype (antibiotic resistant pattern) were used. There were 12 types in PFGE type, 6 types in biotype and 7 types in antibiotype. 1. The predominant types were PFGE type A (57.1%), biotype 1 (62.9%), and antibiotype I (resistant for oxacillin, ampicillin and gentamicin; 34.3%) in Juntendo University Hospital. 2. The strains with antibiotic V-VII (resistant for over 6 antibiotics) showed only PFGE type A and B. All strains with PFGE type B showed biotype 4-6 (negative nitrate reduction strain). 3. The strains having PFGE type A and B were isolated from various patient wards. The strains showing PFGE type A and antibiotype I were isolated from the pediatric ward. 4. There was no strain with PFGE type C or D in 1996. 5. Three patients in whom S. epidermidis was frequently isolated for a few months had the same types of PFGE type, biotype as well as antibiotype.

Blood↗

PubMed1995

Adhesion of Staphylococcus epidermidis to biomedical polymers: contributions of surface thermodynamics and hemodynamic shear conditions.

Adhesion studies of Staphylococcus epidermidis RP62A were conducted using a rotating disk system to determine the roles of surface physicochemistry and topographies under physiologic shear conditions. Six materials were investigated: biomedical reference polyethylene and polydimethylsiloxane; argon plasma-treated reference polyethylene (Ar-PE); Silastic; expanded polytetrafluoroethylene; and woven Dacron. All of the polymers except Dacron demonstrated reduced bacterial adhesion with increasing shear stress. Argon plasma treatment of polyethylene reduced the level of staphylococcal adhesion. Adsorption of human plasma proteins effected significantly lower numbers of adherent bacteria. The lowest adhesion was observed for Ar-PE in 1% human plasma protein solution, whereas Dacron had the highest number of adherent bacteria. The high adhesion on Dacron was attributed to increased bacterial flux caused by topography-induced turbulent flow and physical entrapment of the bacteria in the fiber interstices. The results indicate that the driving force for S. epidermidis adhesion is strongly influenced by substrate physicochemistry, but this may be dominated by physical forces such as shear and turbulence.

Bacterial Adhesion↗

PubMed1996

Influence of strain, biomaterial, proteins, and oncostatic chemotherapy on Staphylococcus epidermidis adhesion to intravascular catheters in vitro.

Initial adhesion of four phenotypically different strains of Staphylococcus epidermidis to 16 silicone, polyurethane, or hydrophilic polyurethane catheters was assessed in vitro by a bacterial radiolabeling method. The effect of catheter exposure to plasma proteins, to an anticancer polychemotherapy (5-fluorouracil, doxorubicin, cyclophosphamide), or to both of them was determined. Bacterial adhesion on native catheters was dependent on the hydrophobicity of both bacteria and catheters. The four strains tested adhered preferentially to silicone catheters (p < 0.05); adhesion was moderate to polyurethane surfaces, whereas the least adhesion was obtained for hydrophilic polyurethane catheters. Adsorption of plasma proteins on the surface produced a marked decrease in adhesion on silicone (-66.2%; p < 0.001) and polyurethane (-32.8%; p < 0.01) catheters and a marked increase in adhesion on hydrophilic surfaces (+91.7%; p < 0.05). Chemotherapeutic treatment of the catheter produced a slight but not significant decrease in adhesion on silicone (-17.4%) and polyurethane (-19.8%) catheters and a marked increase in adhesion on hydrophilic polyurethanes (+148.2%; p < 0.001). The in vitro simulation of catheter use suggested that oncostatic drugs and plasma proteins play an important role in S. epidermidis adhesion to intravascular catheters. Overall, bacterial adhesion is lowest on hydrophilic polyurethane catheters before and after simulation of catheter use.

Adsorption↗

PubMed1999

Heterogeneously vancomycin-resistant Staphylococcus epidermidis strain causing recurrent peritonitis in a dialysis patient during vancomycin therapy.

Methicillin-resistant Staphylococcus epidermidis (MRSE) was recovered over a 2-month period from the dialysis fluid of a peritoneal dialysis (PD) patient who experienced recurrent episodes of peritonitis during therapeutic and prophylactic use of vancomycin. Characterization of five consecutive MRSE isolates by molecular and microbiological methods showed that they were representatives of a single strain, had reduced susceptibility to vancomycin, did not react with DNA probes specific for the enterococcal vanA or vanB gene, and showed characteristics reminiscent of the properties of a recently described vancomycin-resistant laboratory mutant of Staphylococcus aureus. Cultures of these MRSE isolates were heterogeneous: they contained-with a frequency of 10(-4) to 10(-5)-bacteria for which vancomycin MICs were high (25 to 50 microg/ml) which could easily be selected to "take over" the cultures by using vancomycin selection in the laboratory. In contrast, the five consecutive MRSE isolates recovered from the PD patient during virtually continuous vancomycin therapy showed no indication for a similar enrichment of more resistant subpopulations, suggesting the existence of an "occult" infection site in the patient (presumably at the catheter exit site) which was not accessible to the antibiotic.

Adult↗

PubMed1988

Restriction endonuclease analysis of Staphylococcus epidermidis DNA may be a useful epidemiological marker.

We compared the epidemiological markers of 13 Staphylococcus epidermidis strains isolated from an adult inpatient during a febrile episode and 23 S. epidermidis strains isolated during a presumptive outbreak of nosocomial infection in a neonatal ward. The total DNA restriction endonuclease analysis (REA) was processed along with the following conventional markers: biotyping, serotyping, phage typing, antibiotic susceptibility profiles, and plasmid profiles. The REA method was reproducible, giving stable results both in vitro and in vivo. For the hospitalized adult patient, the conventional markers of the 13 strains were concordant and the restriction profiles were identical. Five restriction groups were demonstrated during the course of the outbreak. Within two of the groups, the identities of all of the markers were used to verify whether all of the isolates belonged to the same cell clone. In a third group, combined analysis of the conventional markers and REA had to be used to demonstrate isolate similarity. On the other hand, in another group, none of the markers were similar; interpretation was not easy. An epidemiological study of S. epidermidis infections in hospitals must take into account all of the epidemiological markers: biotypes, serotypes, phage types, antibiograms, plasmid profiles, and REA.

Bacterial Typing Techniques↗

PubMed1998

In vitro studies of pharmacodynamic properties of vancomycin against Staphylococcus aureus and Staphylococcus epidermidis.

The bactericidal activities of vancomycin against two reference strains and two clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis were studied with five different concentrations ranging from 2x to 64x the MIC. The decrease in the numbers of CFU at 24 h was at least 3 log10 CFU/ml for all strains. No concentration-dependent killing was observed. The postantibiotic effect (PAE) was determined by obtaining viable counts for two of the reference strains, and the viable counts varied markedly: 1.2 h for S. aureus and 6.0 h for S. epidermidis. The determinations of the PAE, the postantibiotic sub-MIC effect (PA SME), and the sub-MIC effect (SME) for all strains were done with BioScreen C, a computerized incubator for bacteria. The PA SMEs were longer than the SMEs for all strains tested. A newly developed in vitro kinetic model was used to expose the bacteria to continuously decreasing concentrations of vancomycin. A filter prevented the loss of bacteria during the experiments. One reference strain each of S. aureus and S. epidermidis and two clinical isolates of S. aureus were exposed to an initial concentration of 10x the MIC of vancomycin with two different half-lives (t1/2s): 1 or 5 h. The post-MIC effect (PME) was calculated as the difference in time for the bacteria to grow 1 log10 CFU/ml from the numbers of CFU obtained at the time when the MIC was reached and the corresponding time for an unexposed control culture. The difference in PME between the strains was not as pronounced as that for the PAE. Furthermore, the PME was shorter when a t1/2 of 5 h (approximate terminal t1/2 in humans) was used. The PMEs at t1/2s of 1 and 5 h were 6.5 and 3.6 h, respectively, for S. aureus. The corresponding figures for S. epidermidis were 10.3 and less than 6 h. The shorter PMEs achieved with a t1/2 of 5 h and the lack of concentration-dependent killing indicate that the time above the MIC is the parameter most important for the efficacy of vancomycin.

Anti-Bacterial Agents↗

PubMed2001

Interaction of Staphylococcus epidermidis from infected hip prostheses with neutrophil granulocytes.

This study focuses on the interaction of Staphylococcus epidermidis isolated from granulation tissue covering infected hip prostheses and neutrophil granulocytes. Bacterial strains isolated from normal flora were used as controls. The bacteria were well characterized with routine methods and further characterized with random amplified polymorphic DNA analyses and slime tests. Phagocytosis and chemiluminescence (CL) assays were used in the neutrophil interaction studies. The prostheses strains were ingested to a lesser extent than strains from normal flora (p < or = 0.001). There was no significant difference between the prostheses strains and the normal flora strains in terms of total CL response. However, the extracellular CL response from the neutrophils was lower in comparison with the normal flora when interacting with the prostheses strains. The results of this study support the notion that S. epidermidis strains isolated from infected hip prostheses have an enhanced capacity to resist phagocytosis and that most of these strains elicit a reduced inflammatory response, measured as the production of extracellular oxidative metabolites from the neutrophils, compared to normal flora.

DNA, Bacterial↗

PubMed2004

Influence of batch or fed-batch growth on Staphylococcus epidermidis biofilm formation.

AIMS: To make a quantitative evaluation of the differences in biofilm formation by Staphylococcus epidermidis using batch and fed-batch growth systems and to correlate this with production of the major biofilm polysaccharide, poly-N-acetyl glucosamine (PNAG). METHODS AND RESULTS: Dry weight measurements of biofilms formed in batch and fed-batch conditions were compared with haemagglutination titres, which measure the amount of PNAG produced. Strains grown in batch systems developed less biofilm than when grown in fed-batch systems. A good correlation was found between the amount of biofilm formed in fed-batch systems and the haemagglutination titres. CONCLUSIONS: Differences in biofilm formation and PNAG production by S. epidermidis are dependent on the availability of nutrients, with higher availability correlating with more biofilm and PNAG production. SIGNIFICANCE OF AND IMPACT OF THE STUDY: Comparisons of the formation of biofilms by S. epidermidis are dependent on choosing an appropriate biofilm growth system. Comparability or disparity of conclusions among different investigations will be strongly influenced by which mode S. epidermidis biofilms are formed.

Acetylglucosamine↗

PubMed1996

Potential of exocellular carbohydrate antigens of Staphylococcus epidermidis in the serodiagnosis of orthopaedic prosthetic infection.

The potential of exocellular carbohydrate antigens of Staphylococcus epidermidis as markers of infection in bone was investigated by immunoblotting and enzyme-linked immunosorbent assay (ELISA). Exocellular antigens were prepared by gel filtration chromatography of concentrated brain heart infusion culture supernates. The antigenic material appeared as diffuse bands between 24 and 32 kDa on the immunoblots and was not susceptible to digestion with trypsin, indicating that the response in the patients was to non-protein (polysaccharide or teichoic acid, or both) exocellular material. Significant differences were detected between the immunoblot antigen profiles for serum IgG from patients with S. epidermidis bone infection and those with an uninfected prosthetic joint. Thirteen of 16 patients with S. epidermidis prosthetic joint infection showed an elevated serum IgG level by ELISA compared with controls with uninfected joints. However, the antigen was not specific for S. epidermidis bone infection; high levels of IgG were also detected in patients with other serious staphylococcal and streptococcal infections. The ELISA test may be valuable in distinguishing between staphylococcal infection of joints and aseptic loosening by excluding cases of infection.

Adult↗

PubMed1987

Relationship between cefamandole and cefuroxime activity against oxacillin-resistant Staphylococcus epidermidis and oxacillin resistance phenotype.

The activity of cefamandole and cefuroxime against oxacillin-resistant staphylococcus epidermidis was studied in vitro to determine whether there was any relationship between oxacillin resistance phenotypes and cephalosporin activity. Oxacillin resistance phenotypes were determined by efficiency-of-plating studies on Mueller-Hinton agar containing oxacillin, with and without NaCl, and incubated at 30 and 35 degrees C. On the basis of MIC and MBC determinations, cefamandole was more active than cefuroxime against oxacillin-resistant S. epidermidis. Although temperature had minimal effect on the activity of either cefamandole or cefuroxime, NaCl significantly decreased the activity of cefuroxime but not of cefamandole. Neither cephalosporin consistently produced greater than or equal to 99.9% bactericidal activity within 24 h in timed killing-curve studies. No consistent relationship was observed between cefamandole or cefuroxime activity and oxacillin resistance phenotype.

Cefamandole↗

PubMed2003

Cell surface hydrophobicity and slime production of Staphylococcus epidermidis Brazilian isolates.

The cell surface hydrophobicity of 60 isolates and three reference strains of Staphylococcus epidermidis was assayed by means of bacterial aggregation in liquid broth, phosphate-buffered saline, and in ammonium sulfate, as well as by affinity of the bacteria to n-hexadecane and polystyrene surfaces. In order to better characterize the isolates, the influence of bacterial growth time and enzyme treatment on cell hydrophobicity and the analysis of the slime production were also investigated. The strains presented the following profiles when assayed by the ammonium sulfate aggregation test (SAT): SAT < 1M, SAT 1M - <2M, SAT 2M - <4M, and SAT >or=4M. When SAT < 1M, the strains showed positive results for most of the cell surface hydrophobicity tests. None of the strains belonging to the groups with SAT >or= 1M showed spontaneous aggregation (SA), auto-aggregation (AA), or glass adherence, albeit 32 (62.7%) strains were polystyrene adherent and 42 (82.3%) presented weak adherence to n-hexadecane (>20%). The best correlation of the results was found among the AA and glass adherence tests (100%), followed by SA/ glass adherence (98%) and SA/ AA test (98%). The polystyrene adherence test and microbial adherence to n-hexadecane test (MATH) showed 78% correlation. Proteinase K treatment reduced bacterial adherence to polystyrene, but did not influence the SAT values. Three distinct groups of strains were distinguished by the polystyrene micromethod and glass tube adherence assay: 0.0-0.4 O.D. group, including non-glass adherent isolates; 0.5-0.7 O.D. group, including strains with variable profiles (adherent or non-adherent); and 0.8-1.3 O.D. group, composed of glass-adherent strains. Evaluation by a single method seemed not to reliably determine the surface hydrophobicity characteristics of S. epidermidis clinical isolates. Auto-aggregation properties of the strains that adhered to glass seemed related to slime expression, rather than cell surface hydrophobicity. Data also suggested involvement of protein components in adherence to polystyrene, but not in auto-aggregation properties assayed by SAT.

Adhesiveness↗

PubMed2001

Synthesis of fatty acid esters by recombinant Staphylococcus epidermidis lipases in aqueous environment.

Various flavor esters were obtained by using recombinant lipases from Staphylococcus epidermidis as a catalyst in an aqueous environment. These esters were enzymatically synthesized to overcome the problems associated with chemical processes. This study showed that the S. epidermidis lipases could catalyze ester synthesis from decyl alcohol and fatty acids of different chain length. The wild-type and mutant lipases (M419A and V649I) could efficiently catalyze the synthesis of decyl alcohol esters of unsaturated fatty acids. In contrast, the yield of decyl laurate was better by wild-type and mutant enzyme V6491, but mutant enzyme M419A only favored the synthesis of decyl myristate. The esterification of oleic acid and various carbon-chain-length alcohols from ethanol to hexadecanol increased up to decanol by wild-type and M419A mutant enzymes and reached an optimum for dodecanol by V6491 mutant enzyme. The enzyme is potentially useful in food industries such as dairy product flavoring.

Esterification↗

PubMed1995

Influence of the incubation atmosphere on the production of slime by Staphylococcus epidermidis.

The influence of various incubation atmospheres on the growth and slime production of 23 Staphylococcus epidermidis strains was studied. The atmospheres evaluated were aerobiosis (control), anaerobiosis, candle jar, 5% CO2 and 10% CO2. As compared to the aerobic control, growth was 55.7 +/- 19% (p < 0.01) in anaerobic incubation, 113.7 +/- 12% (p < 0.01) in 5% CO2, 112.8 +/- 13% (p < 0.01) in 10% CO2 and 106.4 +/- 7% (p > 0.1) in the candle jar. The slime production in relation to the aerobic control was 20.3 +/- 19% in anaerobiosis (p < 0.01), 22.3 +/- 27% (p < 0.01) in 5% CO2, 29.4 +/- 39% (p < 0.01) in 10% CO2 and 68.3 +/- 26% (p > 0.1) in the candle jar. The results of this study may explain the discrepancies which have been noted on occasion between slime formation data and pathogenicity.

Aerobiosis↗

PubMed2003

Glucose-related dissociation between icaADBC transcription and biofilm expression by Staphylococcus epidermidis: evidence for an additional factor required for polysaccharide intercellular adhesin synthesis.

Biofilm formation in Staphylococcus epidermidis depends, in the majority of the strains, on the activity of the icaADBC locus. The expression of the operon that encodes the synthetic enzymes of the intercellular polysaccharide adhesin (PIA) depends on a variety of exogenic environmental conditions and is, at least in part, regulated by the alternative sigma factor sigma(B). We investigated the transcriptional regulation of the ica operon and the respective phenotypes expressed under growth conditions differing in the content of glucose in the growth medium. In the presence of glucose, S. epidermidis exhibited a PIA- and biofilm-positive phenotype whereas ica transcription was down-regulated in the postexponential and stationary phases of growth. Surprisingly, maximum transcription of ica was detectable in the stationary phase of growth in the absence of glucose despite the expression of a PIA- and biofilm-negative phenotype. In vitro enzymatic assays and phenotypic characterization showed that the abundant amount of ica mRNA was functionally active because induction of stationary-phase cells with glucose led to immediate PIA synthesis. Induction of biofilm formation could be completely inhibited by chloramphenicol, which, given at a later stage of biofilm accumulation, also inhibited further development of preformed biofilm, indicating that continuous translation of an additional, icaADBC-independent factor is required for the expression of a biofilm-positive phenotype.

Adhesins, Bacterial↗

PubMed1983

Production and partial purification of a peptide antibiotic from Staphylococcus epidermidis.

When grown on solid or in liquid Brain Heart Infusion at 37 degrees C, Staphylococcus epidermidis NCIB 11536 produced antibiotic activity against a wide range of Gram positive bacteria. Production was influenced by aeration, pH, glucose concentration and specific growth rate. Inhibitory activity could be concentrated by ammonium sulphate precipitation (30-55% saturation). On Sephadex G50 using 0.05 mol/l sodium phosphate buffer, pH 6.0, two peaks of antibiotic activity were detected. The first peak eluted with the void volume (Kd = 0) and the second peak was retained by the gel (Kd = 0.73-0.77). These two substances did not represent the monomeric and polymeric forms of a staphylococcal bacteriocin. The low mol. wt inhibitor, which was responsible for over 95% of the recovered activity on Sephadex G50, could be partially purified by a combination of gel filtration on Biogel P2 and ion-exchange chromatography on Sephadex C-25. Yields were increased by combining these two steps into a single procedure (duocolumn). The semi-purified inhibitor was desalted using Sep-pak C18 cartridges. Biological activity was resistant to enzymic denaturation except by high concentrations of trypsin (50 units/micrograms, 3 h, 25 degrees C). This peptide antibiotic is different from any previously described staphylococcal inhibitors.

Adult↗

PubMed1988

In vitro activity of sulbactam/ampicillin and ampicillin against methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

Minimum inhibitory concentrations (MICs) of ampicillin and ampicillin + sulbactam (1:1) against 165 strains of Staphylococcus aureus and 72 strains of Staphylococcus epidermidis have been evaluated. The activity of the combination was very good. A concentration of 16 micrograms/ml + 16 micrograms/ml inhibited 96.9% of S. aureus and the 100% of S. epidermidis strains (at the same concentration ampicillin alone inhibited only 55.15% and 56.9% of S. aureus and S. epidermidis strains respectively). Activity against methicillin-resistant S. aureus (14.5%) was poor, whereas against methicillin-resistant S. epidermidis (67.2%) the combination maintained high efficacy.

Ampicillin↗