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PubMed1997

Phagocytosis and oxidative-burst response of planktonic Staphylococcus epidermidis RP62A and its non-slime-producing variant in human neutrophils.

The ability of bacterial organisms to produce an extracellular polysaccharide matrix known as slime has been associated with increased virulence and delayed infections in various prosthetic implants. Within a biofilm, this slime may protect the embedded bacteria from host defense mechanisms, especially phagocytosis by polymorphonuclear leukocytes. To determine whether planktonic Staphylococcus epidermidis is protected in a similar way, a novel flow cytometric assay was performed, measuring ingestion and adherence during phagocytosis and the production of superoxide during oxidative burst. Hydrophobicity was determined by hydrophobic interaction chromatography. Slime-producing S. epidermidis RP62A and its phenotypic variant, non-slime-producing RP62A-NA, were compared. The results showed increased phagocytosis of RP62A at 2, 5, 10, and 30 min; increased adherence of RP62A at 30 s and 30 min; and increased superoxide production of RP62A after 2 min. Decreased hydrophobicity of RP62A over RP62A-NA was correlated with a hydrophilic slime coat. The data argue that the host aggressively combats slime-producing S. epidermidis. This biological phenomenon is potentially important during bacteremia to prevent further adhesion, accumulation, and the genesis of a bacterial biofilm on implants or tissue surfaces.

Animals↗

PubMed1995

The role of extracellular polysaccharide substance produced by Staphylococcus epidermidis in miliaria.

BACKGROUND: Previous studies have indicated that cutaneous bacteria, particularly coagulase-negative staphylococci, play a role in the pathogenesis of miliaria. An accumulation of periodic acid-Schiff (PAS)-positive material has been described as blocking the sweat duct in miliaria. Furthermore, a PAS-positive extracellular polysaccharide substance (EPS) has been identified as a product of some strains of Staphylococcus epidermidis. OBJECTIVE: We evaluated the relative ability of various species of coagulase-negative staphylococci to induce miliaria with particular reference to the potential role of EPS. METHODS: We inoculated various strains of coagulase-negative staphylococci on the volar forearms of subjects under an occlusive dressing coupled with thermal stimulation. Ability to induce miliaria as well as microbiologic, histologic, and immunostaining features were evaluated. RESULTS: Miliaria was induced only with strains of S. epidermidis; other species including S. haemolyticus, S. hominis, S. cohnii, S. saprophyticus, and S. simulans were not capable of inducing miliaria. Moreover, only S. epidermidis strains capable of producing EPS were capable of inducing miliaria. CONCLUSION: Our data indicate that EPS is the PAS-positive material that obstructs the delivery of sweat to the skin surface in miliaria and therefore demonstrate that the EPS produced by S. epidermidis plays a central role in the pathogenesis of miliaria. Furthermore, in a survey of staphylococcal flora isolated from 68 subjects, EPS-producing strains were found to be common.

Adolescent↗

PubMed2006

Effect of surface proteins on Staphylococcus epidermidis adhesion and colonization on silicone.

Shunt infections are one of the most serious complications in shunt implant surgery. Previous studies have suggested that cerebrospinal fluid (CSF) proteins could affect bacterial adhesion and subsequent shunt infection. A systematic study using immobilized protein on the surface of silane-modified silicone was conducted to determine how these modifications influenced Staphylococcus epidermidis adhesion and colonization. A comparison was also made with silicone having physically adsorbed protein. A colony-counting adhesion assay and scanning electron microscopy (SEM) were used to provide quantitative analysis of bacterial adhesion and semi-quantitative analysis of bacterial colonization, respectively. In order to determine the appropriate silanization process for effective protein immobilization, the effect of bovine serum albumin (BSA) immobilized on n-3-(trimethoxysilyl)propyl-ethylenediamine (AEAPS)/silicone, aminopropyltriethoxysilane (APTMS)/silicone, 3-(glycidyloxypropyl)trimethoxysilane (GPTMS)/silicone, and octadecyltrichlorosilane (OTS)/silicone on bacterial adhesion was investigated. Upon identifying that OTS is the most effective silane, different types of proteins, including: BSA, human serum albumin (HSA), gamma-globulin, and fibrinogen were immobilized on OTS/silicone by a photo-immobilization method. Immobilized protein on modified silicone surfaces was found to be stable in saline for 30 days, while physically adsorbed protein showed instability within hours as determined by contact angle measurements and X-ray photoelectron spectroscopy (XPS). For HSA/OTS/silicone, BSA/OTS/silicone, gamma-globulin/OTS/silicone, fibrinogen/OTS/silicon, and physically absorbed BSA on silicone, the contact angles were 78.5 degrees, 80.7 degrees, 78.9 degrees, 81.3 degrees, and 96.5 degrees; and the amount of nitrogen content was found to be 4.6%, 5.0%, 5.6%, 7.2%, and 3.2%, respectively. All protein immobilized on OTS/silicone surfaces significantly reduced bacterial adhesion by around 75% compared to untreated silicone, while physically adsorbed BSA on silicone reduced by only 29.4%, as determined by colony-counting adhesion assay. However, there was no significant difference on bacterial adhesion among the different types of proteins immobilized on OTS/silicone. Minimizing bacterial adhesion and colonization can be attributed to the increased concentration of -NH2 group, and stability and more hydrophilic nature of the protein/OTS/silicone surfaces.

Animals↗

PubMedDate not supplied

Life-threatening infection with multiresistant Staphylococcus epidermidis in a patient with end-stage renal disease: cure with chloramphenicol and quinupristin/dalfopristin (RP 59500).

A 45-year-old man with end-stage renal disease underwent a cadaveric kidney transplantation. The allograft had to he removed 10 days after transplantation because of an acute vascular rejection. After explantation, the patient suffered from a life-threatening infection with Staphylococcus epidermidis involving lungs, eyes and liver for 11 months. Despite adequate therapy including vancomycin followed by teicoplanin, he developed spondylodiscitis requiring repeated surgical interventions. The definitive cure was achieved by a sequential therapy with chloramphenicol and quinupristin/dalfopristin.

Anti-Bacterial Agents↗

PubMed2005

A microbiological and confocal microscopy study documenting a slime-producing Staphylococcus epidermidis isolated from a nylon corneal suture of a patient with antibiotic-resistant endophthalmitis.

BACKGROUND: We describe a case of posttraumatic endophthalmitis unresponsive to systemic (amoxicillin+clavulanic acid and piperacillin/tazobactam), intra-ocular (vancomycin) and topical (ofloxacin, tetracycline and sulfametoxazole) antibiotic therapy. Microbiological and confocal microscopy studies of a nylon corneal suture revealed the presence of a slime-producing strain of Staphylococcus epidermidis. METHODS: We describe the history and clinical presentation of a 77-year-old man in whom a high-grade posttraumatic endophthalmitis resolved only after the removal of a single nylon corneal suture. Microbiological investigations of the aqueous, vitreous and suture were performed, and the propensity of the suture-associated isolate to form biofilm was assessed using confocal microscopy. RESULTS: A single stain of S. epidermidis was isolated from both aqueous and vitreous specimens and from the suture. The planktonic form of the isolate was susceptible in vitro to the antibiotics administered to the patient, but the strain was capable of forming biofilms and this phenotype showed resistance to high concentrations of the same antibiotics. CONCLUSIONS: The presence of a slime-producing strain of S. epidermidis should be considered in endophthalmitis that is unresponsive to specific antibiotic therapy, especially in cases in which an intra-ocular foreign body (e.g., a suture) is present.

Aged↗

PubMed1992

Amikacin, ceftazidime, and flucloxacillin against suspended and adherent Pseudomonas aeruginosa and Staphylococcus epidermidis in an in vitro model of infection.

Bacterial inocula were exposed as suspended cultures or as adherent biofilms on glass beads in a novel in vitro model of infection to oscillating drug concentrations mimicking human serum kinetics during clinical treatment. Amikacin was given once or thrice daily alone or in combination with ceftazidime or flucloxacillin against Pseudomonas aeruginosa or Staphylococcus epidermidis. Killing of adherent bacteria was significantly reduced during single-drug treatment compared with suspended bacteria (P less than .001), and beta-lactams were more active than amikacin against both suspended and adherent bacteria (P less than .01). Amikacin-beta-lactam combinations killed the inocula more rapidly and were consistently bactericidal against both suspended and adherent pathogens (P less than .05). Once-daily dosing of amikacin produced greater initial killing than thrice daily dosing (P less than .05), but both regimens were similarly effective after 48 h. The differences in antibiotic activity against suspended and adherent bacteria may relate to clinical failures in the treatment of foreign-body infections by bacteria sensitive to the administered antibiotics, as determined by standard susceptibility tests.

Amikacin↗

PubMed2005

In vitro influence of vancomycin on adhesion of a Staphylococcus epidermidis strain encoding intercellular adhesion locus ica to intraocular lenses.

PURPOSE: To assess anti-adhesion and/or bactericidal properties of vancomycin in vitro and to determine when these effects are detectable to estimate its relevance to perioperative antibiotic prophylaxis and analyze the efficacy of a newly designed vancomycin insert prototype for endophthalmitis prevention. SETTING: University research laboratory, Lyon, France. METHODS: Staphylococcus epidermidis clinical strain N890074 containing the intercellular adhesion locus ica was used as the infectious agent. Vancomycin was used at 20 microg/mL. A sterile biocompatible, biodegradable vancomycin insert, releasing 230 microg of antibiotics over 100 minutes, was designed especially for this study. To obtain bacterial killing curves, experiments were first performed in a 103 colony-forming units (CFU/mL) bacterial suspension containing no intraocular lenses (IOL). Then IOLs were incubated in the suspension, and bacterial adherence was determined using bacterial counting with and without antibiotic. RESULTS: Vancomycin (solution and insert) had an anti-adhesion effect after 1 hour and a relevant bactericidal effect after 6 hours of incubation. CONCLUSIONS: Vancomycin used with irrigating solutions does not remain in the anterior chamber long enough to develop bactericidal effect. Even if it initially reduces bacterial adhesion, used at a drug level dropping below the bacterial minimal inhibitory concentration, it could result in a secondary increase of the adhesion of slime-producing bacteria. A sufficiently high concentration was obtained in vitro by the new sustained-release system, thereby overcoming the theoretical drawback of a short half-life within the anterior chamber. Anti-adhesion and bactericidal action of vancomycin inserts remains to be confirmed in clinical studies.

Anti-Bacterial Agents↗

PubMed1999

Application of the quartz crystal microbalance to the monitoring of Staphylococcus epidermidis antigen-antibody agglutination.

The change in solution properties due to the agglutination of an antigen with its specific antibody has previously been used as a marker of infection. This method has been modified to allow the binding activity between species to be followed using the frequency response of a quartz crystal microbalance (QCM). The Bayston agglutination plate assay for Staphylococcus epidermidis has been modified to allow the electrode of a QCM to act as a direct sensor for the change in solution properties as agglutination occurs. Antibody and antigen were introduced to the crystal surface and the agglutination process was followed as a change in crystal resonant frequency. Serum, known to be infected with the organism, gave a titre of 3.9x10(-2)% v/v (-118 Hz, +/-12 SD, N = 9) matching that given by triplicate plate assay. Uninfected serum gave no frequency changes at this concentration, yielding a titre of 2.5x10(-2)% v/v again matching the plate titre (N = 3). Infected serum gave responses 40 times faster then those of the uninfected serum. The piezoelectric quartz crystal method gave a positive or negative diagnosis in <15 min compared with the 24 h required for the plate assay.

Agglutination Tests↗

PubMed1998

Role of monocytes and bacteria in Staphylococcus epidermidis endocarditis.

The endocardial vegetation which is formed in the course of bacterial endocarditis (BE) contains tissue factor (TF)-dependent procoagulant activity. Earlier studies showed that monocytes are the main source of TF in the vegetations. The TF activity (TFA) of vegetations isolated from Streptococcus sanguis-infected rabbits depended on the numbers of bacteria as well as monocytes in the vegetation. In this study, we investigated whether for Staphylococcus epidermidis, a frequent pathogen in BE, an effect similar to that found for S. sanguis could be shown. In vitro, S. epidermidis was found to stimulate TFA of fibrin adherent monocytes significantly. This stimulation was maximal at a bacterium-to-monocyte ratio of 7. In vivo, TFA was found to be significantly higher in S. epidermidis-infected than in sterile catheter-induced vegetations. Reduction of vegetational bacterial numbers by teicoplanin treatment lead to a small but significant decrease of TFA. Reduction of monocyte numbers by etoposide did not affect vegetational TFA. Comparison of data for S. epidermidis and S. sanguis revealed that at equivalent bacterial numbers, vegetational TFAs were approximately the same for both microorganisms. Combining the results of the present study with those of a previous study using S. sanguis, we conclude that the main factor determining monocyte-dependent vegetational TFA is the number of vegetation-associated bacteria. The lower TFA found for S. epidermidis-infected than for S. sanguis-infected vegetations can be explained by the significantly lower bacterial numbers in the infected vegetations and consequently a lower stimulation of vegetation-associated monocytes.

Animals↗

PubMedDate not supplied

Effects of plasma on adhesion of biofilm forming Pseudomonas aeruginosa and Staphylococcus epidermidis to fibrin substrate.

Bacterial adhesion has been identified as the critical initial step in the pathogenesis of foreign body related infection. Recent investigations have shown microbial binding to implanted polymeric materials using specific adhesion of bacteria to immobilized plasma proteins, such as fibrin. These proteins are though to function as bridging molecules to facilitate bacterial colonization of the surface. The authors' results indicated a significant reduction in adhesion of biofilm forming Pseudomonas aeruginosa and coagulase negative Staphylococcus epidermidis to immobilized fibrin strands in the presence of platelet poor plasma (PPP) as compared to studies performed with phosphate buffered saline and Hank's balanced salt solution. A 10-fold decrease in the number of adherent bacteria was noted for samples exposed to PPP as compared to control samples. The effective range of PPP concentrations capable of producing the marked decrease in binding to fibrin strands was determined to be 1-100% for P. aeruginosa and 4-100% for S. epidermidis.

Bacterial Adhesion↗

PubMed2007

Towards a detailed understanding of bacterial metabolism--spectroscopic characterization of Staphylococcus epidermidis.

Bacteria are a major cause of infection. To fight disease and growing resistance, research interest is focused on understanding bacterial metabolism. For a detailed evaluation of the involved mechanisms, a precise knowledge of the molecular composition of the bacteria is required. In this article, various vibrational spectroscopic techniques are applied to comprehensively characterize, on a molecular level, bacteria of the strain Staphylococcus epidermidis, an opportunistic pathogen which has evolved to become a major cause of nosocomial infections. IR absorption spectroscopy reflects the overall chemical composition of the cells, with major focus on the protein vibrations. Smaller sample volumes-down to a single cell-are sufficient to probe the overall chemical composition by means of micro-Raman spectroscopy. The nucleic-acid and aromatic amino-acid moieties are almost exclusively explored by UV resonance Raman spectroscopy. In combination with statistical evaluation methods [hierarchical cluster analysis (HCA), principal component analysis (PCA), linear discriminant analysis (LDA)], the protein and nucleic-acid components that change during the different bacterial growth phases can be identified from the in vivo vibrational spectra. Furthermore, tip-enhanced Raman spectroscopy (TERS) provides insight into the surface structures and follows the dynamics of the polysaccharide and peptide components on the bacterial cells with a spatial resolution below the diffraction limit. This might open new ways for the elucidation of host-bacteria and drug-bacteria interactions.

Bacterial Proteins↗

PubMed1988

Molecular epidemiology of multiresistant Staphylococcus epidermidis.

Molecular epidemiology has provided several clues about the antimicrobial resistance genes of nosocomial, multiresistant coagulase-negative staphylococci. First, it has shown that a huge reservoir of resistance genes is maintained in these organisms on the bodies of both patients and the hospital personnel who care for them. In turn, extensive use of antimicrobial agents within specific sectors of the hospital probably provides selection pressure for the evolution and amplification of these genes. Secondly, indirect evidence suggests that Staphylococcus epidermidis may itself serve as a reservoir for antimicrobial resistance genes that are transferred to S. aureus.

Conjugation, Genetic↗

PubMed1989

Clostridium perfringens and Staphylococcus epidermidis polymicrobial septic arthritis. A case report.

Septic arthritis caused by Clostridium perfringens is extremely rare. Previously there has been only one report of Clostridium perfringens in combination with an aerobe causing septic arthritis. This report presents a 23-year-old man with a mixed aerobic/anaerobic septic arthritis treated with intravenous antibiotics and repeated surgical drainage. It is the only report to date of a polymicrobial septic arthritis involving both Staphylococcus epidermidis and Clostridium perfringens. This report and a review of the literature demonstrate the existence of polymicrobial septic arthritis and illustrate its fulminant nature.

Adult↗

PubMed1983

Experimental Staphylococcus epidermidis endocarditis in rabbit model.

To study the natural course of catheter-induced endocarditis secondarily infected with Staphylococcus epidermidis, 29 rabbits had catheters introduced surgically through the carotid artery to the aortic valve. Forty-eight hours later the catheters were removed from five rabbits. The rabbits were inoculated intravenously with 10(8) colony-forming units of S epidermidis. Autopsies done at various intervals showed all rabbits with indwelling catheters had noticeable aortic valve vegetations with positive cultures for S epidermidis. In the group with catheters removed after 48 hours, less severe valvular lesions were noted. Metastatic seeding to kidneys, spleen, and liver were noted in both groups. Because of low cure rate in the treatment of S epidermidis endocarditis, this rabbit model could be used to study antibiotic regimens for valvular endocarditis.

Animals↗

PubMed1990

Phenotypic variation of Staphylococcus epidermidis in infection of transvenous endocardial pacemaker electrodes.

Coagulase-negative staphylococci isolated from a patient with a pacemaker electrode infection were extensively evaluated by phenotypic and genotypic characterization. Findings from this evaluation were striking because different colony morphologic subtypes were recovered from blood and resected pacemaker electrodes. Staphylococci from each colony subtype (LBL, LBV, LBP, LBS) were identified as slime-producing strains of Staphylococcus epidermidis sensu stricto. Direct plating of isolates from a restricted electrode revealed a mixture of colony phenotypes when examined on a high-salt, low-glucose medium, Memphis agar. Bacteriophage typing employing 17 different phages and plasmid profile analysis were largely unsuccessful in further characterizing bacterial cells of each of the four colony morphotypes. On the other hand, restriction endonuclease analysis by EcoRI digestion of the chromosomal DNA demonstrated the probable common clonal origin of the four colony phenotypes.

Aged↗

PubMed1989

Identification of Staphylococcus epidermidis vascular graft infections: a comparison of culture techniques.

Culture of prosthetic material is routinely used to exclude or implicate infection in the pathogenesis of late-appearing graft complications. In a canine model of aortic graft infection caused by a bacterial biofilm, the influence of culture media (blood agar and tryptic soy broth) and mechanical surface biofilm disruption (tissue grinding and ultrasonic oscillation) on microorganism recovery was determined. Dacron prostheses colonized in vitro with Staphylococcus epidermidis were implanted in the infrarenal aortas of 36 dogs. After 3 weeks an infection with anatomic characteristics of late graft infection in humans was present. Explantation (+/- surface biofilm disruption) of infected grafts showed broth culture was superior (p less than 0.001) to agar media in confirming infection. The recovery rate of S. epidermidis was 30% with agar media, was 72% with broth media alone, and was 83% with broth media plus biofilm disruption. In situ replacement of infected grafts plus parenteral antibiotics resulted in early (1 month) healing of 31 grafts without signs of infection. All replacement grafts were sterile when cultured in broth media alone, but the addition of biofilm disruption isolated the study strain from eight (22%) of 36 grafts (p less than 0.01). Biofilm disruption by tissue grinding or sonication increased bacteria recovery equally. When biofilm bacterial concentration was less than 100 colony-forming units/cm2 of graft, only culture in broth media reliably recovered microorganisms. In the absence of perigraft inflammation, microbiologic recovery techniques that identify bacterial biofilms are necessary to exclude infection in studies concerning the pathogenesis of late graft complications or the treatment of S. epidermidis prosthetic infections.

Animals↗

PubMed1987

Phenotypic variation of Staphylococcus epidermidis slime production in vitro and in vivo.

Clinical studies performed by us and others have found an association between slime production and strains of coagulase-negative staphylococci that infect indwelling medical devices. By serial low-speed centrifugation of broth cultures we have isolated a stable, weakly adherent strain (RP62A-NA) from a strongly adherent, slime-producing, pathogenic strain of Staphylococcus epidermidis sensu stricto (RP62A, ATCC 35984). We obtained a second strain from RP62A-NA (RP62A-NAR) by serial subculture of glass-adherent cells of RP62A-NA. All three strains had the same pattern of biochemical reactions, antimicrobial susceptibilities, and plasmid analysis. Transmission electron micrograph sections stained with the mucopolysaccharide-specific stain alcian blue demonstrated that the adherent strains RP62A and RP62A-NAR were covered with an extracellular coat of polysaccharide-rich material. In contrast, the nonadherent RP62A-NA strain lacked this external coat. All three strains were used in a mouse model of foreign body infection and a rat model of catheter-induced infective endocarditis. The adherence characteristics of isolates of RP62A and RP62A-NA recovered from experimental animals were relatively stable, although we noted a slight but a significant increase in the adherence of RP62A-NA isolates recovered from the foreign body model. The adherence characteristics of RP62A-NAR isolates recovered from infected animals were variable; in general these isolates were less adherent than the laboratory strain of RP62A-NAR. In both models the 50% infective dose (calculated by the Reed and Muench method) was three times greater for the RP62A-NA strain than for the RP62A strain. The phenotypic expression of slime production is subject to both in vitro and in vivo variation and could play a role in the pathogenesis of foreign body infection.

Animals↗

PubMed1989

Antibiotic activity against Staphylococcus epidermidis biofilms in dialysis fluids.

Infection associated with medical devices may be resistant to conventional antibiotic therapy. A potential mechanism explaining this variable therapeutic response is the presence of bacterial biofilms on the surface of the prosthetic material which may confer a biologically important protective function to the entrapped bacteria. To study these questions, we prepared standardized biofilms and conventional fluid phase cultures from a panel of ten Staphylococcus epidermidis strains. All ten strains showed in the fluid phase a variable pattern of sensitivity to seven antibiotics but were uniformly sensitive to rifampin and vancomycin. In the biofilm phase they demonstrated solid antibiotic resistance with the variable exception of rifampin. The nature of the milieu was a major variable. Fresh peritoneal dialysis solution enhanced the activity of rifampin but this effect was not present with spent or neutral dialysis fluids.

Bacterial Adhesion↗