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PubMed1988

Neonatal Staphylococcus epidermidis right-sided endocarditis: description of five catheterized infants.

Coagulase-negative staphylococci are important causes of bacteremia and focal infections in infants hospitalized in neonatal intensive care units. The medical records and echocardiograms of 58 newborns with persistent Staphylococcus epidermidis bacteremia who were hospitalized in the neonatal intensive care unit at The New York Hospital during the past 5 1/2 years were reviewed, and five infants were identified as having S epidermidis right-sided infective endocarditis. These episodes were associated with placement of umbilical venous catheters in the right atrium, slow resolution of bacteremia, and persistent thrombocytopenia. This experience suggests the role of endocardial trauma resulting from the placement of umbilical venous catheters in the pathogenesis of endocarditis. The increasing importance of coagulase-negative staphylococci as a cause of bacteremia in the newborn may explain the emergence of S epidermidis as an important cause of infective endocarditis in the neonatal intensive care unit. These cases underscore the potential severity of S epidermidis infection in the premature newborn.

Catheterization↗

PubMed2006

Biofilm-forming ability profiling of Staphylococcus aureus and Staphylococcus epidermidis mastitis isolates.

Biofilm-forming ability has been increasingly recognized as an important virulence factor in Staphylococci, facilitating their persistence in the host, evading its defences and allowing bacterial survival at high antimicrobial concentrations. Staphylococcus aureus remains a major pathogen of chronic mastitis, but in the last years Staphylococcus epidermidis has emerged as a relevant mastitis pathogen. The present work aimed at the evaluation of the biofilm-forming ability of Staphylococci field isolates from bovine subclinical mastitis and at the development of a fluorescent in situ hybridisation (FISH) protocol that would allow the direct observation of biofilm formation in milk samples. The analysis of phenotypic expression in Congo Red Agar (CRA) and by FISH, showed that 37.5% of the S. aureus isolates produced biofilm, while by optical density measurement only 18.75% isolates revealed this phenotype. The results showed a fair agreement according to the kappa coefficient test (kappa = 0.259). Regarding S. epidermidis mastitis isolates, 37.5% revealed the ability to produce biofilm, but only four isolates were positive by all methods. This agreement was moderate (kappa = 0.467). The application of FISH to artificially contaminated milk samples allowed the direct observation of biofilm production by 37.5% isolates, showing total agreement with the CRA results. This method better mimics the in vivo conditions, especially in terms of the presence of calcium and iron, which in high concentrations, respectively, are known to inhibit or induce biofilm production.

Animals↗

PubMed1997

Factors affecting development of rifampicin resistance in biofilm-producing Staphylococcus epidermidis.

Selection and regrowth of variants resistant to 0.016-32 mg/L of rifampicin, which were present at a frequency of 10(-7) in the initial inoculum, were seen when large inocula (> 10(5) cfu/mL) of Staphylococcus epidermidis ATCC 35984 were incubated with the drug. Conventional MIC determinations using approximately 10(5) cfu/mL did not detect the resistant variants. Larger inocula increased the MIC by > 8000-fold. Population analysis showed that rifampicin concentrations above the MIC (measured at an inoculum of approximately 10(5) cfu/mL) select highly resistant variants (MIC > 256 mg/L) when large inocula (> or = 10(5) cfu/mL) were incubated with rifampicin. The resistant variants were stable through ten passages. It was not possible to prevent regrowth of the resistant variants by increasing the rifampicin concentration further. At subinhibitory concentrations there was no development of rifampicin resistance.

Antibiotics, Antitubercular↗

PubMed1972

Serological typing of Staphylococcus epidermidis strains by the serum-soft agar technique.

Antisera to five different diffuse forms of Staphylococcus epidermidis were prepared in rabbits as a mean of serological differentiation of S. epidermidis strains. These antisera converted the growth types of the homologous strains from diffuse to compact form in serum-soft agar but did not convert the heterologous strains. The converting activities of the antisera were absorbed out with homologous organisms and not by heterologous strains, indicating the specific serological properties of these strains. Further, the converting activity was absorbable with cell surface substance extracted by sonic oscillation and was not absorbed with cells from which this surface substance had been removed. With these factor sera and the serum-soft agar technique, S. epidermidis strains were differentiated, and it was found that 102 of 116 strains or 87.9% were typable. Within the 102 typable strains, 49 and 53 typed as monovalent and polyvalent, respectively. No correlation between source and strain types of S. epidermidis was found.

Adsorption↗

PubMed1993

Effect of dialysis on the clearance of Staphylococcus epidermidis from the peritoneal cavity: an experimental evaluation.

Current information on the effect of peritoneal dialysis on host defenses in the peritoneal cavity is limited to in vitro studies. In the present study, clearance of Staphylococcus epidermidis from the abdominal cavity was assessed in an animal model undergoing peritoneal dialysis. In non-manipulated subjects, challenges of up to 10(8) viable microorganisms were cleared from the peritoneal cavity over a period of 24-48 hours. Cannula implantation, short- and long-term dialysis and the presence of excessive amounts of fluid in the peritoneal cavity did not affect the clearance rate. Presentation of the bacterial challenge, either as a bolus or via a slow delivery system, likewise had no effect on clearance rates. The results suggest that microbial trophism and the characteristics of the invading pathogen may be more critical determinants of the outcome of an infectious challenge to the peritoneal cavity than the status of the cellular and humoral defense systems.

Animals↗

PubMed1994

Transposon mutants of Staphylococcus epidermidis deficient in elaboration of capsular polysaccharide/adhesin and slime are avirulent in a rabbit model of endocarditis.

Virulence comparisons were made in a rabbit model of endocarditis between wild-type and transposon mutants of Staphylococcus epidermidis deficient in elaboration of the capsular polysaccharide/adhesin (PS/A) and slime. The parental phenotype grew from 36 (61%) of 59 cultures of blood. The PS/A-negative phenotype grew in 1 (1%) of 98 cultures of blood (P < .001). No animals infected with PS/A-negative strains developed endocarditis compared with 75% of rabbits infected with PS/A-positive strains. PS/A-producing strains survived better than did PS/A-deficient strains in intact, absorbed rabbit or human serum plus human leukocytes. There was also greater deposition of C3 onto the PS/A-deficient strains than with the PS/A-producing isogenic strains. PS/A functions as an antiphagocytic bacterial capsule preventing C3 deposition and phagocytosis; loss of this structure increases the strain's susceptibility to opsonic killing and decreases its virulence.

Analysis of Variance↗

PubMed1997

Molecular typing of Staphylococcus epidermidis and other CNS with repetitive element sequence-based PCR.

The chromosomal distribution of the repetitive DNA sequence found in Mycoplasma pneumoniae (REP-MP2) provides an ideal target for detecting DNA fragment patterns specific to individual Staphylococcus epidermidis and S. haemolyticus strains. A REP-MP2 sequence-based PCR (rep-PCR) was developed and applied to CNS isolates. We identified a 450 bp genomic DNA fragment which was common and specific to S. epidermidis isolates and not found in other CNS. In addition, S. epidermidis isolates showed several bands that could be grouped into 14 different fragment patterns. Similarly, S. haemolyticus isolates were classified into 10 groups. Significant correlations between the typing patterns of S. epidermidis and resistance to oxacillin (P< 0.05), gentamicin (P< 0.01), erythromycin (P< 0.02), and sulfamethoxazole-trimethoprim (P< 0.001) were found. The rep-PCR method is a rapid and reproducible discriminatory means for molecular typing of S. epidermidis and other CNS.

Anti-Bacterial Agents↗

PubMed2002

Efficacy of quinupristin-dalfopristin in preventing vascular graft infection due to Staphylococcus epidermidis with intermediate resistance to glycopeptides.

A rat model was used to investigate the efficacy of quinupristin-dalfopristin (Q-D) in the prevention of vascular prosthetic graft infection due to methicillin-resistant Staphylococcus epidermidis with intermediate resistance to glycopeptides. The in vitro activity of the compound was compared to that of vancomycin by MIC determination and time-kill study. Moreover, the efficacy of collagen-sealed Q-D-soaked Dacron was evaluated in a rat model of graft infection. Graft infections were established in the subcutaneous tissue of the backs of 120 adult male Wistar rats. The in vivo study included a control group, one contaminated group that did not receive any antibiotic prophylaxis, two contaminated groups that received grafts soaked with 10 and 100 micro g of Q-D per ml, respectively, and two contaminated groups that received grafts soaked with 10 and 100 micro g of vancomycin per ml, respectively. Rats that received Dacron grafts soaked with 100 micro g of Q-D per ml showed no evidence of infection (<10 CFU/ml). In contrast, for rats that received Dacron grafts soaked with 10 micro g of Q-D per ml and Dacron grafts soaked with 10 or 100 micro g of vancomycin per ml, the quantitative graft cultures demonstrated 2.2 x 10(2) +/- 1.3 x 10(2), 2.2 x 10(6) +/- 1.9 x 10(5), and 5.6 x 10(2) +/- 0.3 x 10(2) CFU/ml, respectively. Taken together the results of the study demonstrate that the use of Dacron grafts soaked with Q-D can result in significant bacterial growth inhibition and show that this compound is potentially valuable for prevention of vascular prosthetic graft infection.

Animals↗

PubMed2005

Role of silver ions in destabilization of intermolecular adhesion forces measured by atomic force microscopy in Staphylococcus epidermidis biofilms.

In this paper, we report on the potential use of atomic force microscopy (AFM) as a tool to measure the intermolecular forces in biofilm structures and to study the effect of silver ions on sessile Staphylococcus epidermidis cell viability and stability. We propose a strategy of destabilizing the biofilm matrix by reducing the intermolecular forces within the extracellular polymeric substances (EPSs) using a low concentration (50 ppb) of silver ions. Our AFM studies on the intermolecular forces within the EPSs of S. epidermidis RP62A and S.epidermidis 1457 biofilms suggest that the silver ions can destabilize the biofilm matrix by binding to electron donor groups of the biological molecules. This leads to reductions in the number of binding sites for hydrogen bonds and electrostatic and hydrophobic interactions and, hence, the destabilization of the biofilm structure.

Anti-Bacterial Agents↗

PubMed1986

Treatment of experimental methicillin-resistant Staphylococcus epidermidis endophthalmitis with intravitreal vancomycin.

Endophthalmitis remains a dreaded complication of intraocular surgery and penetrating eye trauma. Subconjunctival, topical, and systemic antibiotics have been largely ineffective in the treatment of endophthalmitis, whereas intravitreal antibiotics have proved efficacious. Methicillin-resistant Staphylococcus epidermidis has become an important pathogen in many infections, including endophthalmitis. Toxicity, clearance, and efficacy of intravitreal vancomycin were evaluated in the treatment of experimental methicillin-resistant S. epidermidis endophthalmitis. No evidence of retinal toxicity was found and therapeutic levels were demonstrated six days after injection. The treated rabbit eyes showed a marked beneficial effect when compared to the untreated eyes. If experience confirms the safety of intravitreal vancomycin in human eyes, vancomycin should be considered the drug of choice for methicillin-resistant S. epidermidis endophthalmitis.

Animals↗

PubMed2006

Detection of biofilm formation in Staphylococcus epidermidis from implant infections. Comparison of a PCR-method that recognizes the presence of ica genes with two classic phenotypic methods.

Biofilm-forming ability is increasingly being recognized as an important virulence factor in Staphylococcus epidermidis. This study compares three different techniques for the detection of biofilm-positive strains. The presence of icaA and icaD genes responsible for biofilm synthesis was investigated by a PCR method in a collection of 80 S. epidermidis strains isolated from orthopedic implant infections. The results from molecular analysis were compared with those obtained by two classic phenotypic methods, the Congo red agar (CRA) plate test and the microtiter plate test (MtP). Fifty-seven percent of all the examined strains were found icaA/icaD-positive, of which only three were not positive for CRA test. Differently, by the MtP method, 66% of the strains were found to be biofilm-producers but only a limited agreement with the PCR-method was noticeable because of the observation of (icaA/icaD+)/MtP- strains (8%) and of a surprising ambiguous result of (icaA/icaD-)/MtP+ strains (16%). The category of the weak biofilm-producers provided the highest contribution to these mismatching results (10%). The better agreement between the CRA plate test with the molecular detection of ica genes indicates the former as a reliable test for the phenotypic characterization of virulence of clinical isolates. However, MtP method remains a precious tool for the in vitro screening of different biomaterials for the adhesive properties using a reference strain.

Bacterial Adhesion↗

PubMed1993

Diffusion of rifampin and vancomycin through a Staphylococcus epidermidis biofilm.

Using an equilibrium dialysis chamber, we evaluated the penetration of vancomycin, rifampin, or both through a staphylococcal biofilm to simulate treatment of an infected biomedical implant. A biofilm of ATCC 35984 (slime-positive Staphylococcus epidermidis; vancomycin MIC and MBC, 1 and 2 micrograms/ml, respectively; rifampin MIC and MBC, 0.00003 and 0.00025 micrograms/ml, respectively) was established on the inner aspect of the dialysis membrane (molecular mass exclusion, 6,000 kDa). Serum containing vancomycin (40 micrograms/ml), rifampin (20 micrograms/ml), or a combination of both was introduced into the inner chamber of the dialysis unit (in direct contact with the biofilm), and serum alone was added to the outer chamber. Rifampin and vancomycin concentrations in both chambers were determined over a 72-h period. In the absence of rifampin, the concentration of vancomycin in the outer chamber exceeded the MBC for the organism after 24 h, and the MBC increased to nearly 8.0 micrograms/ml by 72 h, demonstrating that therapeutic levels of vancomycin can penetrate a staphylococcal biofilm. However, viable bacteria were recovered from the biofilm after 72 h of treatment with no apparent increase in the MIC or MBC of vancomycin. Similarly, concentrations of rifampin exceeding the MBC were detected in the outer chamber after 24 h of treatment, but viable organisms were recovered from the biofilm after 72 h of treatment. In this case, the rifampin MBCs for surviving organisms increased from 0.00025 to > 128 micrograms/ml. The combination of agents prevented the development of resistance to rifampin, improved the perfusion of vancomycin through the biofilm, and decreased the penetration of rifampin but did not sterilize the membrane. These observations provide evidence that bactericidal levels of vancomycin, rifampin, or both can be attained at the surface of an infected implant. Despite this, sterilization of the biofilm was not accomplished after 72 h of treatment.

Bacterial Adhesion↗

PubMed1995

[Septic lung caused by methicillin-resistant Staphylococcus epidermidis].

A 55-year-old man was admitted to our department one month after resection of rectal carcinoma, with complaints of fever and general malaise. Shock developed rapidly after admission. The chest X-ray film and computed tomography showed diffuse small nodular shadows and bilateral pleural effusion. Septic lung caused by Methicillin-resistant Staphylococcus epidermidis (MRSE) was diagnosed from the results of a bacteriological study. This bacteria is a Coagulase Negative Staphylococcus (CNS). Chemotherapy with Minocycline and Cefotiam was effective. Characteristic radiologic features of this case may be related to the early stage of adult respiratory distress syndrome (ARDS) and septic pulmonary microembolism.

Anti-Bacterial Agents↗

PubMed2004

Presence of fibrinogen-binding adhesin gene in Staphylococcus epidermidis isolates from central venous catheters-associated and orthopaedic implant-associated infections.

Attention has recently been paid to identify and elucidate those pathogenetic mechanisms, which play a significant role in sustaining the early phases of Staphylococcus epidermidis colonisation and infection development. Several analogies with the physiology of Staphylococcus aureus, a more thoroughly investigated pathogen, have lead to carefully consider all bacterial surface components that mediate cell adhesion. This study aimed at investigating the presence of the fbe gene encoding for a fibrinogen-binding protein in a collection of 107 S. epidermidis strains isolated from orthopaedic infections and 67 from central venous catheter-associated infections. The strains isolated from orthopaedic infections were in large part associated to four different classes of orthopaedic devices, respectively: internal fixation devices, external fixation devices, knee arthroprostheses and hip arthroprostheses. The molecular epidemiology analysis performed by PCR enlightened a statistically significant difference in the prevalence of this adhesion mechanism between orthopaedic infections and catheter-related infections, respectively, of 78% and 91%. The prevalence of fbe ranged from 67% to 91%, suggesting that, even though this adhesin is not strictly necessary for the development of infection, nevertheless it represents a rather common characteristic of strains causing clinical infections, this independently on the presence or the absence of implant materials.

Bacterial Proteins↗

PubMedDate not supplied

An assay to measure antibiotic efficacy against Staphylococcus epidermidis biofilms on implant surfaces.

Infection is a major limitation of implantable devices. Optimal antibiotic therapeutic regimes have not yet been defined. Implant-associated infections have a number of differentiating characteristics, which include the predominance of Staphylococcus epidermidis and other skin bacteria of normally low pathogenicity as the causative agents, together with a relative resistance to host defenses and to antibiotic therapy. These properties have been ascribed to the ability of the bacteria to exist on implant surfaces in the biofilm phase, which is protective. An assay of antibiotic activity using a standardized bacterial biofilm preparation of S. epidermidis is described. The assay is used to evaluate the relative efficacy of antibiotics to sterilize the biofilm, when they are used singly, or in double or triple combinations. The modulating effects of changing antibiotic concentrations and modifying the environment with CAPD variables (fresh and spent dialysis fluid, common PD solution additives) are also measured and the data summarized. It is hoped that, by using this and similar assays, individualized optimal therapeutic regimes of implant-associated infections may be logically planned.

Anti-Bacterial Agents↗

PubMed2004

Erratum to "Apotransferrin administration prevents growth of Staphylococcus epidermidis in serum of stem cell transplant patients by binding of free iron". [FEMS Immunol. Med Microbiol. 37 (2003) 45-51].

We investigated the effect of free, non-transferrin-bound iron occurring in haematological stem cell transplant patients on growth of Staphylococcus epidermidis in serum in vitro, and prevention of bacterial growth by exogenous apotransferrin. S. epidermidis did not grow in normal serum at inoculated bacterial densities up to 10(3) cfu ml(-1) but slow growth could be detected at higher initial inocula. Addition of free iron abolished the growth-inhibitory effect of serum, whereas addition of apotransferrin again restored it. Appearance of free iron and loss of growth inhibition coincided in patient serum samples taken daily during myeloablative therapy. Intravenously administered apotransferrin effectively bound free iron and restored the growth inhibition in patient sera. The results suggest that exogenous apotransferrin might protect stem cell transplant patients against infections by S. epidermidis and possibly other opportunistic pathogens.

Apoproteins↗

PubMed1993

Tissue plasminogen activator and Staphylococcus epidermidis endophthalmitis.

OBJECTIVE: To determine whether intraocular administration of tissue plasminogen activator (tPA) speeds clearance of inflammatory debris or prevents fibroproliferative complications in an animal model of endophthalmitis. METHODS: Aphakic rabbits were given an intraocular dose of Staphylococcus epidermidis organisms known to cause moderate inflammation and to self-sterilize. They were then randomized to receive either tPA or saline injections 2 and 3 days after inoculation. All eyes were graded by one masked clinician seven times, 1 to 28 days after infection. Vitreous samples from selected eyes were cultured. RESULTS: Treated and control eyes were found to have no significant difference in inflammatory scores. Although the eyes treated with tPA had more retinal detachments and more positive cultures than control eyes, these numbers were not statistically significant (P = .44 to .71). CONCLUSION: Fibrinolysis with intraocular tPA does not accelerate clearance of inflammation nor decrease fibroproliferative complications in this animal model of endophthalmitis.

Animals↗

PubMedDate not supplied

Staphylococcus epidermidis septic arthritis post arthroscopy.

A 61 year-old man developed painful swelling of his right knee shortly after arthroscopy of the joint. Synovial fluid analysis revealed a polymorphonuclear leukocytosis of 51,600 X 10(6) cells/litre and culture grew Staphylococcus epidermidis. He responded favorably to 4 weeks of intravenous therapy with cloxacillin. S. epidermidis, an important cause of prosthetic joint infection, must be considered a potential pathogen in other joint infections.

Arthritis, Infectious↗