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PubMed2006

Increased osteoblast and decreased Staphylococcus epidermidis functions on nanophase ZnO and TiO2.

Many engineers and surgeons trace implant failure to poor osseointegration (or the bonding of an orthopedic implant to juxtaposed bone) and/or bacteria infection. By using novel nanotopographies, researchers have shown that nanostructured ceramics, carbon fibers, polymers, metals, and composites enhance osteoblast adhesion and calcium/phosphate mineral deposition. However, the function of bacteria on materials with nanostructured surfaces remains largely uninvestigated. This is despite the fact that during normal surgical insertion of an orthopedic implant, bacteria from the patient's own skin and/or mucosa enters the wound site. These bacteria (namely, Staphylococcus epidermidis) irreversibly adhere to an implant surface while various physiological stresses induce alterations in the bacterial growth rate leading to biofilm formation. Because of their integral role in determining the success of orthopedic implants, the objective of this in vitro study was to examine the functions of (i) S. epidermidis and (ii) osteoblasts (or bone-forming cells) on ZnO and titania (TiO(2)), which possess nanostructured compared to microstructured surface features. ZnO is a well-known antimicrobial agent and TiO(2) readily forms on titanium once implanted. Results of this study provided the first evidence of decreased S. epidermidis adhesion on ZnO and TiO(2) with nanostructured when compared with microstructured surface features. Moreover, compared with microphase formulations, results of this study showed increased osteoblast adhesion, alkaline phosphatase activity, and calcium mineral deposition on nanophase ZnO and TiO(2). In this manner, this study suggests that nanophase ZnO and TiO(2) may reduce S. epidermidis adhesion and increase osteoblast functions necessary to promote the efficacy of orthopedic implants.

Anti-Bacterial Agents↗

PubMed2006

Human immunoglobulin G recognizing fibrinogen-binding surface proteins is protective against both Staphylococcus aureus and Staphylococcus epidermidis infections in vivo.

A human donor-selected immunoglobulin G for intravenous injection (IGIV) product with elevated titers against the staphylococcal fibrinogen-binding MSCRAMM proteins ClfA and SdrG (INH-A21) was tested in vitro and in vivo. INH-A21 contained a significantly increased ability to inhibit the fibrinogen-binding activity of recombinant forms of both ClfA and SdrG. Evaluation of the opsonizing potential of INH-A21 was evaluated using fluorescently labeled bacteria; this assay indicated an increase in phagocytic activity compared to normal IGIV. The prophylactic efficacy of INH-A21 against an intraperitoneal challenge of methicillin-resistant Staphylococcus epidermidis (MRSE) was evaluated in a neonatal rat model. INH-A21 was also evaluated for prophylactic and therapeutic efficacy in a rabbit model of catheter-induced aortic valve infective endocarditis caused by either MRSE or methicillin-resistant Staphylococcus aureus (MRSA). Results from the in vivo models demonstrated potent prophylactic and therapeutic efficacy against both MRSE and MRSA. These data suggest that INH-A21 may be an important tool for the prevention and treatment of staphylococcal infections, especially in high-risk populations.

Animals↗

PubMed1980

Successful management of bacterial endocarditis of the mitral valve due to Staphylococcus epidermidis in an immunosuppressed host.

We report the successful management of bacterial endocarditis of the mitral valve, caused by Staphylococcus epidermidis, in a 34-month-old boy with acute lymphocytic leukemia who had been receiving immunosuppressive therapy. M-mode echocardiography provided early detection of valvular vegetations and documented the evolution of valvular involvement during the course of the illness.

Anti-Bacterial Agents↗

PubMed2000

Performance of phenotypic and genotypic methods to determine the clinical relevance of serial blood isolates of staphylococcus epidermidis in patients with septicemia.

Five typing methods, including biotyping (API ID32; BioMérieux, Marcy l'Etoile, France), quantitative antibiogram typing based on actual zone sizes, plasmid typing, randomly amplified polymorphic DNA (RAPD) analysis (with primer M13 and primer set ERIC-2-1026), and pulsed-field gel electrophoresis (PFGE), were compared with a previously performed method of DNA fingerprinting by AFLP (amplified fragment length polymorphism analysis) for their performance in the typing of blood isolates of Staphylococcus epidermidis. Sixteen epidemiologically unrelated strains and 11 sets of four blood culture isolates from 11 patients with septicemia were used. The stabilities and reproducibilities of the patterns, the discriminatory capacities of the methods, and the ability to apply the methods to blood culture isolates were used as performance criteria. All strains tested were typeable by each method, and the patterns were stable and reproducible. The numbers of different types within the collection of 16 epidemiologically different isolates were 5 by biotyping, 14 by antibiogram typing, 4 by plasmid typing, 9 by the RAPD assay (combination of results with primer M13 and primer set ERIC-2-1026), and 16 by PFGE. Within the 11 sets of four blood culture isolates the types found by quantitative antibiogram typing, plasmid typing, and PFGE were unique for each set, whereas by biotyping and RAPD analysis some types were observed in more than one set. The results of biotyping did not correspond with the results of the other methods or the results of AFLP. For 6 of the 11 sets, the results of all methods except those of biotyping corresponded completely. Quantitative antibiogram typing, PFGE, and AFLP proved to be the most accurate of the six typing methods tested.

Bacteremia↗

PubMed1998

The ica locus of Staphylococcus epidermidis encodes production of the capsular polysaccharide/adhesin.

Clinical isolates of coagulase-negative staphylococci often elaborate a biofilm involved in adherence to medical devices and resistance to host defenses. The biofilm contains the capsular polysaccharide/adhesin (PS/A), which mediates cell adherence to biomaterials, and another antigen, termed polysaccharide intercellular adhesin (PIA), which is thought to mediate bacterial accumulation into cellular aggregates. PIA is a polymer of beta-1, 6-linked N-acetyl glucosamine residues with a molecular mass of <30, 000 kDa. We found that recombinant Staphylococcus carnosus and Staphylococcus aureus carrying a plasmid with genes of the ica locus, which was reported to encode the biosynthetic proteins for production of PIA, were also able to synthesize PS/A. PS/A and a chemically and immunologically identical polysaccharide isolated from S. carnosus carrying the ica genes on plasmid pCN27 were found to be high-molecular-mass (>250,000 kDa), acid-stable polymers of beta-1,6-linked glucosamine substituted on the amino group primarily with succinate, although some preparations also contained acetate. Moreover, all recombinant staphylococcal strains with the ica genes had the biologic properties previously attributed to PS/A. ica-positive strains readily formed an in vitro biofilm on plastic, adhered 3- to 10-fold more to catheters during a 30-min assay compared with control strains carrying only the cloning vector, adsorbed out antibodies to PS/A from immune serum, and elaborated a capsule visualized by immunoelectron microscopy with antisera to PS/A. These properties were also seen with PS/A-producing strains of Staphylococcus epidermidis, but not with transposon mutants lacking PS/A. An antiserum raised to PIA contained high-titer antibody to PS/A that was readily adsorbed out by PS/A-positive strains of S. epidermidis and recombinant strains of staphylococci carrying the ica genes. We conclude that the ica locus encodes production of PS/A and that the properties of S. epidermidis associated with initial bacterial adherence, biofilm formation, and intercellular adhesion can be correlated with elaboration of PS/A.

Adhesins, Bacterial↗

PubMed1991

Nosocomial Staphylococcus epidermidis septicaemia among very low birth weight neonates in an intensive care unit.

A cluster of cases of septicaemia caused by coagulase-negative staphylococci was observed among the infants at the Neonatal Intensive Care Unit (NICU) of the Karolinska Hospital in May 1987. The presence of a unique antibiogram among the blood culture isolates prompted an investigation to determine whether an epidemic strain existed or not, using antibiogram, biotyping and plasmid profiles as epidemiological markers. All 14 isolates with a unique antibiogram were investigated, and 22 isolates without the unique antibiogram served as controls. Of the 14 isolates, 11 were Staphylococcus epidermidis and had similar plasmid patterns. Of the 22 control isolates, 15 were S. epidermidis, and none had the special plasmid pattern nor any other recurring plasmid patterns. The use of plasmid profile analysis together with antibiograms thus identified a possible epidemic strain of S. epidermidis which may have been responsible for the upsurge of septicaemia cases at the NICU. The presence of an epidemic strain implies that hospital cross infection control could be important in preventing neonatal septicaemia caused by S. epidermidis.

Coagulase↗

PubMed2001

Vancomycin resistance among strains of Staphylococcus epidermidis: effects on adherence to silicone.

Nosocomial device-related infections with Gram-positive cocci and their resistance to vancomycin are of increasing occurrence. We examined clinical isolates of relatively avirulent coagulase-negative staphylococci for their resistance to vancomycin and for their capabilities to adhere in vitro to medical grade silicone. Vancomycin resistance was found in 9 of 20 isolates, but there was no correlation between adherence capacity to silicone in the absence of vancomycin and vancomycin resistance for a given strain. Vancomycin in the medium, adsorbed to the surface of medical grade silicone or adsorbed on nongrowing cells, reduced adherence of representative Staphylococcus epidermidis to medical grade silicone.

Adsorption↗

PubMed1995

The effect of ethanol ingestion on killing of Streptococcus pneumoniae, Staphylococcus aureus and Staphylococcus epidermidis by rat neutrophils.

The precise effects of chronic ethanol ingestion on the role of neutrophil function in pneumococcal pneumonia have not been fully delineated. In this study, the bactericidal capacity of polymorphonuclear leucocytes (PMNL) from rats pair-fed an ethanol-containing liquid diet or a liquid control diet was compared both in vitro and in vivo. The PMNL were allowed to phagocytose several bacterial species in vitro, and intracellular killing after 1h was determined by plate counts. There was no significant difference in killing of Streptococcus pneumoniae types 6B or 37, Staphylococcus aureus or Staphylococcus epidermidis by PMNL from ethanol-fed and pair-fed rats (E-PMNL and P-PMNL, respectively). However, E-PMNL killed significantly less of Streptococcus pneumoniae types 10A, 14 and 19F. To corroborate these results in vivo, rats were infected transtracheally, and quantitative lung counts were performed 1 week post infection. Streptococcus pneumoniae types 6B and 37, as well as Staphylococcus aureus, were effectively cleared from the lungs of both groups of rats. Streptococcus pneumoniae types 10A, 14 and 19F, however, were cleared well from the lungs of pair-fed but not ethanol-fed animals. These data suggest that chronic ethanol ingestion induces a strain-specific deficit in neutrophil bactericidal activity against certain S. pneumoniae which does not extend to commonly encountered staphylococci.

Alcoholism↗

PubMed2005

Electric block current induced detachment from surgical stainless steel and decreased viability of Staphylococcus epidermidis.

In vitro studies investigating the influence of electric DC current on bacterial detachment have demonstrated that continuous currents of only 25-125 microA stimulated staphylococcal strains to detach from surgical stainless steel. However, DC currents produce more power that has to be dissipated by the skin as compared to alternating currents. Also, an excess of ions on the steel can cause negative osteogenesis and fixation results. Therefore, it is the aim of this paper to examine whether detachment of Staphylococcus epidermidis from stainless steel surfaces in a parallel plate flow chamber can also be stimulated using electric block currents. Block currents of 15, 60 and 100 microA with different frequencies (0.1-2 Hz) and duty cycles (5-50%) were applied to induce bacterial detachment. Block currents of 100 microA cause detachment of about 76% of adhering staphylococci from stainless steel, whereas in addition the remaining bacteria are less viable, as determined by culturing the remaining bacteria on agar plates. Therewith, block current-induced detachment of adhering bacteria from stainless steel appears to be an equally promising method to prevent infection of orthopaedic fixation pins and screws than application of DC currents.

Adsorption↗

PubMed1990

Posterior infectious crystalline keratopathy with Staphylococcus epidermidis.

Two cases of infectious crystalline keratopathy located in the posterior stroma after penetrating keratoplasty are presented. Topical steroids and suture removal were risk factors in both cases. In the first case, a moderate anterior chamber reaction was present. Crystalline infiltrates persisted on topical and systemic steroid therapy. In the second case, deep corneal ulceration, hypopyon, and vitreitis were noted. A vitreous aspirate showed rare gram-positive cocci in pairs. The corneal ulceration and crystalline keratopathy persisted despite intravitreal and topical antibiotics. Therapeutic penetrating keratoplasty was performed in both cases. Staphylococcus epidermidis sensitive to vancomycin was isolated from corneal tissue. Light microscopy documented aggregates of gram-positive bacteria anterior to Descemet's membrane, with an overlying keratitis. Electron microscopy in the second case showed all bacteria within stromal keratocytes. No clinical recurrence was seen using topical vancomycin. As demonstrated in the cases presented, infectious crystalline keratopathy can occur exclusively in the deeper layers of the cornea. Isolation of S. epidermidis, associated inflammation, and intraocular spread of organisms are rare findings.

Aged↗

PubMed1994

Staphylococcus epidermidis meningitis and an intraspinal abscess associated with a midthoracic dermal sinus tract.

Congenital neuroectodermal defects are associated with meningitis that is unresponsive to conventional antibiotic therapy, recurrent bacterial meningitis, or meningitis due to an organism that is not usually the cause of this disease. Midthoracic dermoid and epidermoid cysts occur rarely and are easily overlooked. We report the case of a 13-month-old boy with meningitis that was unresponsive to antimicrobial therapy. We subsequently identified an intraspinal abscess, an infection due to Staphylococcus epidermidis, and a midthoracic dermoid cyst. We emphasize the need for clinicians to have a high index of suspicion and to make a careful physical examination when antibiotic treatment fails in patients with meningitis. We also provide a detailed anatomy of a midthoracic dermoid cyst and illustrate the usefulness of magnetic resonance imaging in preoperative diagnosis of congenital neuroectodermal defects.

Abscess↗

PubMed2003

Establishment of an arbitrary PCR for rapid identification of Tn917 insertion sites in Staphylococcus epidermidis: characterization of biofilm-negative and nonmucoid mutants.

Transposon mutagenesis with the Enterococcus faecalis transposon Tn917 is a genetic approach frequently used to identify genes related with specific phenotypes in gram-positive bacteria. We established an arbitrary PCR for the rapid and easy identification of Tn917 insertion sites in Staphylococcus epidermidis with six independent, well-characterized biofilm-negative Tn917 transposon mutants, which were clustered in the icaADBC gene locus or harbor Tn917 in the regulatory gene rsbU. For all six of these mutants, short chromosomal DNA fragments flanking both transposon ends could be amplified. All fragments were sufficient to correctly identify the Tn917 insertion sites in the published S. epidermidis genomes. By using this technique, the Tn917 insertion sites of three not-yet-characterized biofilm-negative or nonmucoid mutants were identified. In the biofilm-negative and nonmucoid mutant M12, Tn917 is inserted into a gene homologous to the regulatory gene purR of Bacillus subtilis and Staphylococcus aureus. The Tn917 insertions of the nonmucoid but biofilm-positive mutants M16 and M20 are located in genes homologous to components of the phosphoenolpyruvate-sugar phosphotransferase system (PTS) of B. subtilis, S. aureus, and Staphylococcus carnosus, indicating an influence of the PTS on the mucoid phenotype in S. epidermidis.

Bacterial Adhesion↗

PubMed2000

Polycationic peptides as prophylactic agents against methicillin-susceptible or methicillin-resistant Staphylococcus epidermidis vascular graft infection.

Several polycationic peptides isolated from animals, plants, and bacterial species possess a broad spectrum of antimicrobial activity. A rat model was used to investigate the efficacies of two peptides, ranalexin and buforin II, in the prevention of vascular prosthetic graft infections. The effect of peptide-soaked collagen-sealed Dacron was compared to that of rifampin-soaked collagen-sealed Dacron in the rat model of graft infection caused by methicillin-susceptible rifampin-susceptible Staphylococcus epidermidis and methicillin-resistant rifampin-susceptible S. epidermidis. Graft infections were established in the back subcutaneous tissue of 240 adult male Wistar rats by implantation of 1-cm(2) Dacron prostheses, followed by topical inoculation with 2 x 10(7) CFU of S. epidermidis. The study included a control group (no graft contamination), two contaminated groups that did not receive any antibiotic prophylaxis, two contaminated groups to which perioperative intraperitoneal cefazolin prophylaxis (30 mg/kg of body weight) was administered, six contaminated groups that received a peptide- or rifampin-soaked graft, and six contaminated groups that received a peptide- or rifampin-soaked graft and perioperative intraperitoneal cefazolin prophylaxis (30 mg/kg). The grafts were sterilely removed 7 days after implantation, and the infection was evaluated by using sonication and quantitative agar culture. Overall, the efficacies of the polycationic peptides against the methicillin-susceptible and methicillin-resistant strains were not significantly different from that of rifampin. Nevertheless, the combinations of ranalexin- and buforin II-coated grafts with cefazolin treatment demonstrated efficacies significantly higher than that of the combination of rifampin-coated grafts and cefazolin treatment against the methicillin-resistant strain.

Animals↗

PubMed1998

Development of an in-vitro model to study the growth characteristics of Staphylococcus epidermidis in continuous ambulatory peritoneal dialysis.

An in-vitro model of peritonitis in continuous ambulatory peritoneal dialysis (CAPD) has been developed which integrates the parameters of environmental gaseous tension, the changing biochemical profile of the dialysate, and the periodic challenge of fresh fluid. Dwell times of 4 h during the day and 10 h at night were used to reflect the in-vivo situation. Biochemical analysis of dialysate within the model showed that the profiles for creatinine, glucose and protein approximated those found in patients. Staphylococcus epidermidis growing in synthetic dialysis effluent or pooled dialysis fluid were seen to adapt rapidly to the environment after an initial lag phase; a tendency to aggregate together increased over the 50-h period of operation. In conclusion, the results presented here suggest that this in-vitro model creates an environment which is reflective of the in-vivo situation and therefore has potential for the study of peritonitis in CAPD.

Cell Division↗

PubMed2003

Fitness of antibiotic resistant Staphylococcus epidermidis assessed by competition on the skin of human volunteers.

BACKGROUND: Antibiotic resistance typically confers a biological fitness cost on bacteria that can be manifested as a decreased growth rate in culture media and experimental animals. However, there are limited experimental data on the relative fitness of resistant and susceptible bacteria during growth in their natural environment. OBJECTIVE: We have developed a human competition model to investigate the relative fitness of antibiotic-resistant and -susceptible bacteria. MATERIALS AND METHODS: A non-epidemic Staphylococcus epidermidis strain was isolated from skin, and a rifampicin-resistant (RifR) clone was selected. The RifR marker was used to distinguish the inoculated strains from the resident population of coagulase-negative staphylococci. The RifR strains were further selected for resistance to ciprofloxacin (CipR) and fusidic acid (FusR). A 1:1 mix of susceptible and resistant bacteria was applied on the forearms of 12 volunteers. Competition was monitored by sampling bacteria from skin and determining their relative numbers. RESULTS: Resistance to ciprofloxacin due to parC mutations did not decrease the growth rate in vitro, and the CipR/CipS ratio was close to 1 during day 1 and 3 in the in vivo competition experiments. In contrast, fusidic acid resistance due to fusA mutations resulted in a decrease in the growth rate in vitro and a considerable loss of fitness in the competition. The FusR/FusS ratio diminished from 1.3 to 0.023 in 3 days. CONCLUSIONS: These data show that human volunteers can be used as a simple and relevant model to study the biological cost of resistance.

Drug Resistance, Bacterial↗

PubMed1995

Cultures from genitourinary prostheses at reoperation: questioning the role of Staphylococcus epidermidis in periprosthetic infection.

PURPOSE: We determine the colony counts of organisms present on culture of clinically uninfected genitourinary prostheses at reoperation for reasons other than infection. These results served as control data for comparison with cultures from infected devices to determine the relative incidence of organisms involved. MATERIALS AND METHODS: Cultures were prospectively obtained from 65 penile prostheses and 22 artificial urinary sphincters. Patients were followed for a minimum of 12 months after reoperation or until development of infection (mean 27 months) at which time cultures were again obtained. RESULTS: Low colony counts of Staphylococcus epidermidis were isolated from 40% of uninfected penile prostheses and 36% of artificial urinary sphincters. Only 3 of these devices later became infected (9%) and in all cases a higher colony count of another organism was found at explanation. CONCLUSIONS: While Staph. epidermidis can cause prosthesis infection, low colony counts of the organism may not be associated with clinical infection. Therefore, the high incidence of infection attributed to this organism may be overestimated.

Case-Control Studies↗

PubMed1978

Purification and characterization of an aminoglycoside inactivating enzyme from Staphylococcus epidermidis FK109 that nucleotidylates the 4'- and 4''-hydroxyl groups of the aminoglycoside antibiotics.

The resistance to aminoglycoside antibiotics in Staphylococcus epidermidis FK109, is mediated by an enzyme that catalyzes transfer of the nucleotide monophosphate moiety from the nucleotide triphosphates, either to the 4'-hydroxyl group, that is in the equatorial plane of the aminoglycoside molecule. The enzyme, modifying the two sites, appears as a single and homogeneous entity in affinity chromatography, in chromatography on DEAE-Sepharose CL-6B, in isoelectric focusing and in gel-filtration. It requires divalent cations, notably Mg++, and dithiothreitol for optimal adenylylation. It has a molecular weight of 46,770 and an isoelectric point of 5.0. The ability of the enzyme ANT (4', 4'') to modify the two hydroxyl groups of aminoglycoside molecules, enables it to have a spectrum of substrates that surpasses, in range, the substrate spectrum of all the aminoglycoside-modifying enzymes which have been characterized hitherto.

Aminoglycosides↗

PubMed2001

Treatment of methicillin-resistant Staphylococcus epidermidis infection following repair of an ulnar fracture and humeroradial joint luxation in a horse.

A 27-month-old Rocky Mountain Horse was examined because of a fracture of the proximal portion of the ulna and luxation of the humeroradial joint (Monteggia fracture). Open reduction was performed, using a mechanical distractor, and the ulnar fracture was stabilized by application of a bone plate and screws. After surgery, the horse developed an infection of the surgical site, and bacterial culture of fluid from the surgical site yielded a pure growth of methicillin-resistant Staphylococcus epidermidis susceptible to oxytetracycline, erythromycin, rifampin, and vancomycin. Treatment with oxytetracycline did not result in a favorable clinical response. Therefore, the horse was treated systemically with vancomycin and rifampin, and vancomycin-impregnated polymethyl methacrylate beads were implanted at the surgical site. Six months after surgery, the horse was sound at a walk or trot, and bony union was evident on radiographs of the elbow joint.

Animals↗