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PubMed2005

Effect of vancomycin, teicoplanin, and cefuroxime on Staphylococcus epidermidis adherence to intraocular lenses.

PURPOSE: To compare the adherence of Staphylococcus epidermidis on AcrySof (Alcon) and poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) treated with vancomycin, teicoplanin, and cefuroxime. SETTING: Kocaeli University, School of Medicine, Kocaeli, Turkey. METHODS: The lenses were contaminated with S epidermidis solutions containing 10(8) colony-forming units. Intraocular lenses were placed in sterile triptic soy broth after being held in antibiotic solutions for 15 minutes. After that, sonication and vortex procedures were performed to remove all the attached bacteria that could not be removed by antibiotics. Ten microliters from each broth were taken and inoculated into sheep blood agar. The colonies were counted overnight. The statistical analyses were made using Mann-Whitney U and Kruskal-Wallis tests, and a P value less than 0.05 was considered statistically significant. RESULTS: Regarding the inhibitory effect of antibiotics on bacterial adhesion, there was no statistically significant difference between AcrySof and PMMA lenses. In the cefuroxime group, the mean numbers of colony-forming units on AcrySof and PMMA lenses were 35.2 +/- 6.94 and 30.8 +/- 18.69, respectively (P>.05). In the teicoplanin group, the mean number of colony-forming units on AcrySof lenses was 100.1 +/- 20.97 and 70.6 +/- 43.75 on the PMMA lenses. The adherence in the vancomycin group was 245 +/- 273.74 colony-forming units for AcrySof lenses and 159.8 +/- 101.94 for PMMA lenses (P>.05). Regarding the inhibitory effect of antibiotics, cefuroxime was the most effective, followed by teicoplanin and vancomycin, respectively. Overall, the mean numbers of colony-forming units on the lenses that were held in cefuroxime, teicoplanin, and vancomycin solutions were 33.0 +/- 13.90, 85.35 +/- 36.66, and 202.4 +/- 205.74, respectively (P = .000). CONCLUSIONS: The results suggest that cefuroxime, teicoplanin, and vancomycin significantly inhibit bacterial adherence to IOLs. The effect of cefuroxime on adherence inhibition was significantly higher than that of teicoplanin and vancomycin. Bacterial adherence is an important factor in bacterial virulence. Antibiotics, especially cefuroxime, can successfully inhibit bacterial adherence.

Acrylic Resins↗

PubMed2005

Genetic diversity among methicillin-resistant Staphylococcus epidermidis (MRSE).

We selected 106 methicillin-resistant Staphylococcus epidermidis (MRSE) and 22 methicillin-susceptible S. epidermidis (MSSE) hospital isolates--each with a different PFGE pattern--for more detailed documentation of genetic diversity. The 106 MRSE isolates showed extensive variation in the SmaI DNA fragments hybridizing with the DNA probe for mecA, the molecular size of which varied from as low as 20 kb up to over 500 kb. Parallel variation was also observed in the size of DNA fragments hybridizing with the chromosomal genes orfX and gyrA, and this was also observed in MSSE isolates. In contrast, SmaI fragments associated with the housekeeping genes murE and aroE, both located distantly from orfX, showed little size variation. Typing for the mec complex and ccr identified 10 different SCCmec structures and a large number of strains (21 isolates) that were non-typeable. The majority of strains studied (36%) carried a SCCmec type IV-like structure, including strains with non-related PFGE profiles. On the other hand, closely related strains often carried different types of SCCmec. The findings indicate that the acquisition and/or loss of mobile genetic elements, including various structural types of SCCmec, may occur frequently in the vicinity of the orfX gene on the S. epidermidis chromosome.

Bacterial Proteins↗

PubMed1978

Treatment of necrotizing fasciitis caused by Staphylococcus epidermidis.

Postoperative necrotizing fasciitis with septicemia caused by Staphylococcus epidermidis was documented by cultures of the blood and wound biopsy specimen. Therapy consisted of surgical debridement, topical application of mafenide acetate dressings, and parenteral administration of cefazolin sodium. The combination effectively reversed the progression of infection and necrosis.

Abdominal Muscles↗

PubMed2002

Detection of the icaADBC gene cluster and biofilm formation in Staphylococcus epidermidis isolates from catheter-related urinary tract infections.

Biofilm production in Staphylococcus epidermidis is an important virulence factor that is mediated by the expression of the icaADBC operon. In this study 41 S. epidermidis isolates obtained from catheter-related urinary tract infections were analyzed for the presence of the icaADBC operon and biofilm formation. Eighteen of 41 isolates (44%) were shown to carry ica-specific DNA, but only 11 isolates (27%) produced biofilms spontaneously under normal growth conditions. Upon induction by external stress or antibiotics, biofilm formation could be stimulated in five of seven ica-positive, biofilm-negative isolates, indicating that the icaADBC expression was down-regulated in these strains. Genetic analyses of the ica gene clusters of the remaining two ica-positive, biofilm-negative strains revealed a spontaneous ICAC::IS256 insertion in one strain. Insertion of the element caused a target site duplication of seven base pairs and a biofilm-negative phenotype. After repeated passages the insertion mutant was able to revert to a biofilm-forming phenotype which was due to the precise excision of IS256 from the icaC gene. The data show that icaC::IS256 integrations occur during S. epidermidis polymer-related infections and the results highlight the biological relevance of the IS256-mediated phase variation of biofilm production in S. epidermidis during an infection.

Biofilms↗

PubMed1998

Trimethoprim resistance and susceptibility genes in Staphylococcus epidermidis.

Genes encoding trimethoprim (TMP)-resistant and -susceptible dihydrofolate reductases (DHFR) in Staphylococcus epidermidis isolated in Saitama Prefecture were compared with the TMP-resistant DHFR gene of S. aureus, dfrA. The nucleotide sequences of TMPr and TMPs genes in five S. epidermidis isolates tested could be divided into three types: type 1, identical with the TMPr gene dfrA that had been found in S. aureus; type 3, identical with the TMPs gene dfrC in S. epidermidis; and type 2, having only two nucleotide substitutions to dfrC with no amino acid change. TMPr isolates carried either one of the type 2 or type 3 sequences in addition to the type 1 sequence. A Southern hybridization analysis revealed that, in TMPr S. epidermidis, the type 1 sequence was located on a 5.5 kb EcoRI-EcoRV restriction fragment together with the sequence for the gentamicin (GM)-resistant gene, while the type 2 or type 3 sequence was located on the 1.0 kb EcoRI-EcoRV fragment. No plasmid-carrying dfrA-homologous sequence was detected in the S. epidermidis isolates we tested. These results suggest that the TMPr and GMr genes are closely linked and located on the chromosome in S. epidermidis isolated in Japan.

Amino Acid Sequence↗

PubMed2004

Electric-current-induced detachment of Staphylococcus epidermidis strains from surgical stainless steel.

Infection of percutaneous biomaterials implants, such as fixation frames used for the repair of complicated fractures in orthopedics, is a major complication that almost inevitably leads to replacement of the implant. As antibiotic therapy usually has little impact on biomaterial-associated infections, it is the aim of this article to examine whether implant-associated Staphylococcus epidermidis and Staphylococcus aureus strains could be stimulated to detach from a surgical stainless steel anode during application of an electric current. First, bacteria were allowed to adhere from a flowing suspension of physiological ionic strength in a parallel plate flow chamber to a stainless-steel surface, after which the suspension was replaced by a bacterium-free solution with a specified ionic strength (0.5-150-mM potassium phosphate). DC currents ranging from 15 to 125 microA were applied to induce bacterial detachment. Initial detachment decreased with increasing ionic strength at 100 microA. The percentage detachment achieved by application of an electric current after 2.5 h was highest (95%) in 1-mM potassium phosphate and decreased to 15% when the ionic strength exceeded 40 mM. The electric current did not significantly affect the percentage detachment, but initial detachment rates increased with increasing current from 1000 cm(-2) s(-1) at 15 microA to 7000 cm(-2) s(-1) at 125 microA. Although different isolates of S. epidermidis and S. aureus showed different patterns of current-induced detachment, all strains could be stimulated to detach. The results of this study define ionic-strength conditions and electric currents yielding staphylococcal detachment from surgical stainless steel and therewith point to a pathway for the treatment and prevention of percutaneous metal-implant infection.

Electric Stimulation↗

PubMed2001

Synergy of different antibiotic combinations in biofilms of Staphylococcus epidermidis.

The in vitro effect of nine antibiotic combinations was investigated in Staphylococcus epidermidis biofilms using ATP-bioluminescence for viable bacterial cell quantification. Four slime-producing (SP) strains were used to form biofilms 6, 24 and 48 h old. These biofilms were exposed for 24 h to antibiotics at 4 x, 2 x, 1 x and 0.5 x MIC. Combinations involving tetracycline together with another antibiotic were the most efficient at the biofilm age and concentration range under study. The combination vancomycin-rifampicin produced the highest bactericidal effect on 6 h biofilms at 4 x MIC, but this effect decreased dramatically in older biofilms. To detect possible antibiotic synergy in combinations that had a significant killing effect, antibiotics were studied not only in combination but also individually. Synergic effects were observed in all the combinations tested. Differences between the effect in combination and the sum of individual antibiotic effects (degree of synergy) were significant (mostly P< 0.001) and exceeded 1 log10 cfu/mL in the majority of cases. In 48 h biofilms, antibiotics caused a significant bactericidal effect when applied in combination, but never when used individually. These results indicate that the biofilm test applied allows the detection of synergy between antibiotics and suggests that this assay could be useful in clinical and extensive synergy studies on S. epidermidis biofilms.

Anti-Bacterial Agents↗

PubMed1993

Fibronectin and proteolytic fragments of fibronectin interfere with the adhesion of Staphylococcus epidermidis to plastic.

The adhesion of five strains of slime-positive Staphylococcus epidermidis to plastic microwells was significantly diminished (P < 0.005) in a concentration-dependent fashion when wells were previously coated with increasing concentrations (1.6-13.1 micrograms cm-2) of human fibronectin (FN). The adhesion of four of five strains was significantly reduced when wells were coated with 3.2 micrograms cm-2 of FN and at concentrations > or = 6.5 micrograms cm-2 the adhesion of all slime-positive strains was significantly reduced. The coating of microwells with chymotryptic fragments of FN containing the heparin-binding, gelatin-binding, or cell-binding domains also reduced bacterial adhesion but none of the fragments exceeded the anti-adhesive activity of intact FN. A comparison of FN-coated or albumin-coated microwells showed that both proteins caused a significant reduction in the adhesion of test strains to plastic but that the anti-adhesive activity of FN was greater than albumin at all concentrations tested. The adhesion of the slime-negative phase variant of one of the test strains to plastic was neither enhanced nor reduced by FN coating indicating that the production of an exopolysaccharide by Staph. epidermidis influences interactions with protein-coated surfaces. These results support the contention that FN does not mediate the adhesion of all strains of Staph. epidermidis to plastic surfaces.

Bacterial Adhesion↗

PubMed1975

Efficacy of phage typing epidemiologically related Staphylococcus epidermidis strains.

A total of 118 epidemiologically related Staphylococcus epidermidis strains from hospital patients, staff, and fomites were examined with a provisional set of 18 typing phages. Seventy (59.3%) of these strains were typed using phage concentrations of 100 times routine test dilution. The remainder were nontypable. Thirty-six (30.5%) of the strains were of related phage types, 71/108/275A/459 and 71/108/275A. These latter strains were associated with clinical S. epidermidis endocarditis in patients with prosthetic valve replacements. Ninety-eight strains were characterized by the Baird-Parket biotyping schema. Eighty-three (84.7%) were biotype 1, and the majority (68.4%) of these were resistant to penicillin, ampicillin, methicillin, cephalothin, erythromycin, and clindamycin. Type 71, 71/108/275A/459, 71/108/275A and 71/108/275/459 strains were generally resistant to penicillin, ampicillin, erythromycin, and methicillin, whereas a less consistent resistance pattern was noted among miscellaneous and nontypable strains.

Anti-Bacterial Agents↗

PubMed1994

Opsonic antibodies to Staphylococcus epidermidis: in vitro and in vivo studies using human intravenous immune globulin.

Staphylococcus epidermidis is a major cause of nosocomial infections, including sepsis in premature infants. Intravenous immune globulin (IVIG) has been used to prevent neonatal sepsis, but efficacy has varied in different clinical trials. The role of IgG antibody in immunity to S. epidermidis was studied using an opsonophagocytic assay and a lipid-emulsion-induced lethal model of neonatal S. epidermidis sepsis. Opsonic antibody to S. epidermidis varied between IVIG preparations and between lots: Lots with > or = 90% opsonic activity promoted bacterial clearance from blood and significantly enhanced survival when compared with lots with < or = 50% opsonic activity. Absorption of IVIG with S. epidermidis removed in vitro opsonic and in vivo protective activity. These studies suggest that opsonic antibody may play an important role in S. epidermidis immunity in immunocompromised patients, such as premature infants. Standard IVIG, however, may not provide therapy effective in preventing S. epidermidis infections, as many IVIG lots contain insufficient levels of opsonic S. epidermidis antibody.

Animals↗

PubMed1992

The typing of Staphylococcus epidermidis by a lectin-binding assay.

A new typing method for Staphylococcus epidermidis was developed. Four biotinylated lectins--wheat germ agglutinin (WGA), soy bean agglutinin (SBA), lentil agglutinin (LCA) and Concanavalin A (ConA)--were added to immobilised whole cells of coagulase-negative staphylococci (CNS) in microtitration plates. The amount of bound lectin was measured by peroxidase-conjugated avidin followed by a peroxidase reaction. The method was compared to antibiotic-resistance analysis, phage typing, plasmid DNA profiles and slime production. A total of 113 isolates of CNS from 21 patients was investigated and 71 strains of CNS, including 64 strains of S. epidermidis, were detected if all typing methods were taken into consideration. If only one typing method was used the highest discriminatory power among the S. epidermidis isolates was obtained with the lectin-binding assay which allowed 49 different strains to be detected. If the lectin-binding assay was combined with plasmid-profile analysis, all 64 different strains could be identified. The typability of lectin-binding assay was 96.9% among the S. epidermidis isolates and 25 different lectin-binding patterns were established among the 64 strains. The highest number of strains belonging to one lectin-binding pattern was 13 (20.3%). The assay was reproducible, easy to perform, relatively inexpensive and therefore applicable to large scale typing of S. epidermidis.

Bacterial Typing Techniques↗

PubMed1995

Comparative virulence of Staphylococcus epidermidis isolates in a murine catheter model.

Among coagulase-negative staphylococci, Staphylococcus epidermidis is the species most commonly implicated in catheter-related infections. Whether some staphylococcal organisms are inherently more virulent than others, or whether their ability to infect relates more to the sheer numbers of organisms at the catheter site, remains unclear. We therefore compared eight S. epidermidis isolates and two other coagulase-negative staphylococci using a murine model that allowed us to quantify catheter colonization and abscess formation in the same animal. The organisms were isolated from different clinically relevant settings and were classified according to their slime phenotype. The ability to evoke abscesses or colonize catheters in half of the animals (ID50) was assessed. ID50 inoculum titers (log10 data +/- SD) ranged widely, from 8.5 +/- 0.3 to 10.2 +/- 0.2 for abscess formation (p < 0.005) and from 7.5 +/- 0.5 to 10.3 +/- 1.0 for catheter colonization (p < 0.005). ID50 values by statistical criteria suggested variability among organisms in the ability to induce abscess formation. High slime production correlated with both parameters, but not with the clinical source of the isolate. Our findings demonstrate impressive heterogeneity in the ability of a representative group of S. epidermidis isolates to colonize catheters and to evoke abscess formation and implicate slime productivity as a major virulence factor. The murine model used permitted simultaneous analysis of multiple factors involved in pathogenesis and should be useful in establishing the basis of S. epidermidis pathogenicity.

Abscess↗

PubMed1981

Effect of starvation on transport, membrane potential and survival of Staphylococcus epidermidis under anaerobic conditions.

When washed suspensions of Staphylococcus epidermidis were starved under anaerobic conditions the viability declined to less than 10% within 12 h. Although RNA was slightly degraded during this period the principal substrate for endogenous metabolism was protein and the intracellular amino acid pool. The adenylate energy charge and the ability to transport serine declined markedly within the first 6 h of starvation. With the majority of batches of organism investigated the membrane potential, as measured by the accumulation of Cs+ by valinomycin-treated organisms, also decreased significantly during this period. Addition of glucose or serine during starvation reversed these effects to varying extents provided that feeding took place during an early phase (2 h) of starvation. There was no apparent correlation between the magnitude of the membrane potential and viability.

Adenosine Triphosphate↗

PubMed1972

Mode of action of a Staphylococcus epidermidis bacteriocin.

Staphylococcin 1580, a bacteriocin produced by Staphylococcus epidermidis 1580, is bactericidal to sensitive cells of many gram-positive bacteria and stable staphylococcal L-forms. The bacteriocin inhibited simultaneously the syntheses of deoxyribonucleic acid, ribonucleic acid, and protein, and caused neither degradation of deoxyribonucleic acid nor induction of phages in lysogenic, sensitive cells. After 1 hr of treatment, extensive degradation of ribonucleic acid occurred, which was accompanied by leakage of ultraviolet-absorbing material out of the cell. The incorporation of glucose in acid-precipitable and glycogenlike material was inhibited. Furthermore, the staphylococcin inhibited the transport of glucose, glutamic acid, rubidium ions, and o-nitrophenyl-beta-galactoside. The uptake of oxygen was only gradually affected, but the intracellular adenosine triphosphate level fell rapidly to 15% of the control value. The motility of sensitive Bacillus subtilis cells was markedly reduced on treatment. Staphylococcin 1580 exhibited no phospholipase activity. The phenomena are interpreted as resulting from an altered conformation and composition of the membrane, from an inhibition of transport through the membrane, or from a combination of these effects.

Bacteriocins↗

PubMed1977

Development of a bacteriophage-typing set for Staphylococcus epidermidis.

Six phages isolated from lysogenic cultures of Staphylococcus epidermidis were used to type cultures in our collection classified previously as "untypable" with our original typing set of 13 phages, new clinical isolates from Missouri, and clinical isolates from Connecticut, Georgia, Pennsylvania, and Virginia. Typability with the new set of 6 phages and with our 13 original phages was compared. For 203 cultures, 81 (39.9%) cultures were typable with the set of 6 phages and 73 (36.0%) cultures were typable with the set of 13 phages. When the two typing sets were combined, the percentage of typability for 425 cultures increased to 49.9%. compared with 35.7% with the original set of 13 phages. For 109 cultures from outstate, the percentage of typability was 56.9%, whereas that for 316 cultures from Missouri was 47.5%. When only cultures in biotype 1 were considered, the percentage of typability for 268 cultures with the combined set increased to 58.2%, compared with 39.5% with the original set of 13 phages. Analysis of individual reactions for all 425 cultures typed in our laboratory indicated that 11 of the 19 phages in the combined set accounted for the majority of the reactions, and a provisional set containing these 11 phages is proposed.

Bacteriophage Typing↗

PubMed1991

Characterization of cell envelope proteins of Staphylococcus epidermidis cultured in human peritoneal dialysate.

The cell envelope protein profiles of Staphylococcus epidermidis cultured in used human peritoneal dialysate (HPD) differed markedly from those of cells cultured in nutrient broth. Compared with broth-grown cells, many cell wall proteins were repressed in HPD, although three proteins of 42, 48, and 54 kDa predominated and an iron-repressible 130-kDa protein was induced. Growth in HPD also resulted in expression of two cell membrane proteins of 32 and 36 kDa which were iron repressible. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis using monospecific polyclonal antisera raised against the 32- and 36-kDa proteins revealed considerable antigenic and molecular mass homology among 12 S. epidermidis isolates from patients with continuous ambulatory peritoneal dialysis-related peritonitis. The 32-kDa antiserum also cross-reacted with a 32-kDa S. aureus cell membrane protein. Immunoblots of S. epidermidis cell walls and membranes were also probed with normal human serum and serum and HPD from continuous ambulatory peritoneal dialysis patients. While the cell wall proteins of S. epidermidis appeared to be relatively poorly immunogenic, the 32- and 36-kDa membrane proteins reacted strongly with antibodies present in each of the body fluids evaluated. These results suggest that the highly conserved 32- and 36-kDa iron-repressible proteins are expressed during growth in vivo and may be involved in iron transport, since all 12 S. epidermidis strains examined also produced iron chelators.

Bacterial Proteins↗

PubMed1994

Methicillin-resistant Staphylococcus epidermidis in infection of hip arthroplasties.

We investigated the incidence of cephalosporin-resistant bacteria in infected hip arthroplasties. Of 740 patients having hip replacement or related procedures performed over three years, 30 had positive bacteriological cultures from tissue removed at the time of surgery. In 18 of the 30 cultures Staphylococcus epidermidis was grown and 12 of these were methicillin-resistant. A prospective study of skin swabs taken from 100 consecutive patients at the time of admission for THR showed methicillin-resistant Staphylococcus epidermidis in 25. This cephalosporin-resistant organism was shown to be the commonest proven cause of infection, and its presence as a skin commensal raises important questions about current antibiotic prophylaxis for joint replacement.

Combined Modality Therapy↗

PubMed2001

Dependence of Staphylococcus epidermidis on non-transferrin-bound iron for growth.

The ability of Staphylococcus epidermidis strains to grow in the presence of human transferrin and varying amounts of ferric iron was studied. At initial bacterial densities up to 10(4) cfu ml(-1), none of the three strains grew when transferrin iron saturation was below the full saturation point, whereas the bacteria grew consistently when transferrin was fully iron-saturated and there was non-transferrin-bound iron in the medium. Precultivation of the bacteria under iron-restricted conditions to induce siderophore production did not abolish the growth dependence on non-transferrin-bound iron. At initial bacterial densities of 10(6) cfu ml(-1), the bacteria proliferated consistently also in the presence of partially saturated transferrin. The results indicate that at low bacterial densities, S. epidermidis cannot utilise transferrin-bound iron for growth and that its proliferation is dependent on non-transferrin-bound iron.

Biological Transport↗