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PubMed1999

Thrombosis of a mitral valve prosthesis resulting from Staphylococcus epidermidis endocarditis.

A 70-year-old man with a Duromedics mitral valve prosthesis had two episodes of infective endocarditis caused by enterococcus (1994 and 1996). Colonoscopy revealed five polyps. Surgical resection was performed and 2 days later the patient had dyspnea and fever. Because of a suspected valve thrombosis, intravenous heparin was given which resulted in hematic effusion in the Douglas' cul-de-sac. Intravenous heparin was withdrawn but the patient continued to have a worsening dyspnea, hyperthermia and hypotension. The patient was transferred to our Institution in cardiogenic shock. Acute thrombosis of the valve was diagnosed by echocardiography, and the patient died before transesophageal Doppler echocardiography was performed. Post mortem examination revealed mitral valve infective thrombosis. In patients with valvular prostheses, endocarditis is an added thromboembolic risk.

Acute Disease↗
PubMed1989

Strain differences in the opsonisation of Staphylococcus epidermidis.

Ten isolates of coagulase-negative staphylococci, collected from patients receiving treatment with continuous ambulatory peritoneal dialysis (CAPD), exhibited marked differences in the degree of opsonisation when incubated in 10% and 1% pooled human serum, 10% and 1% heat-treated serum, Hanks' Balanced Salt Solution, and timed peritoneal dialysis (PD) effluent. The addition of exogenous IgG to PD effluent results in a greater increase in opsonisation in those fluids with the weakest inherent opsonic activity, but is ineffective against the majority of isolates in the absence of heat-labile opsonic activity. The results of this in vitro study suggest that host resistance to CAPD peritonitis due to coagulase-negative staphylococci may be determined as much by the characteristics of the contaminating strain, as by the opsonising activity of PD effluent.

Humans↗
PubMed1989

Immunological detection of penicillin-binding protein 2' in clinical isolates of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

The additional penicillin-binding protein (PBP 2') that is important in determining intrinsic resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA) has been detected immunologically in strains from a variety of world-wide locations. This additional protein has also been definitively identified both immunologically and as a PBP in methicillin-resistant strains of S. epidermidis (MRSE). The assay described is rapid, specific and sensitive and has been used to detect PBP 2' in S. haemolyticus but not in beta-lactam resistant Streptococci.

Acyltransferases↗
PubMed1989

Application of an empirically derived growth curve model to characterize Staphylococcus epidermidis biofilm development on silicone elastomer.

An in vitro model permitting the development of a staphylococcal biofilm on silicone elastomer is described. Biofilm was determined over time by viable cell quantitation for S. epidermidis strains 8-14B, RP62 and SP2. The log10 viable count data were analysed empirically as a function of time using a negative exponential growth curve model. Although initial colonization and biofilm 72 h cell density of silicone was significantly higher for strain RP62 than SP2, biofilm growth rates did not differ. Strain 8-14B demonstrated a faster biofilm growth rate for the initial 24 h than did RP62 or SP2. The statistical model described was sensitive enough to detect strain differences in biofilm development on silicone elastomer and can be further employed to evaluate the ability of selected biomaterials to retard biofilm development, and the ability of various antimicrobial agents to influence biofilm microbe development.

Biocompatible Materials↗
PubMed1993

Detecting methicillin-resistant Staphylococcus epidermidis--disc diffusion, broth breakpoint or polymerase chain reaction?

Growth conditions are important for the expression of resistance to methicillin among staphylococci. Consequently a phenotypic susceptibility test has to be chosen carefully to avoid false susceptible results. In this study we wanted to devise rapid and simple phenotypic tests whose results completely correlate with the presence of the methicillin resistance gene, mecA. A simplified polymerase chain reaction (PCR) method not needing separate DNA extraction from the tested bacteria was used to amplify a 449 bp region of the mecA gene. One hundred and ten strains of S. epidermidis were tested. The results were in complete agreement with those from a broth tube breakpoint test, known to identify more strains as resistant than does the method recommended by NCCLS. In disc diffusion test it was possible to clearly distinguish resistant from susceptible strains by using discs containing oxacillin, cephalexin and cephradine. A 5 micrograms cephradine disc was further analysed by testing another 441 consecutive clinical isolates of staphylococci. All resistant coagulase-negative staphylococci grew out to the edge of this disc, whereas susceptible strains showed an inhibition zone at least 10 mm in diameter. The 5 micrograms cephradine disc is recommended for routine work. The PCR method and broth tube breakpoint test are both reliable reference methods.

Base Sequence↗
PubMed2001

[Correlation between methicillin-resistance and resistance to fluoroquinolones in Staphylococcus aureus and Staphylococcus epidermidis].

Fluoroquinolones resistance in Staphylococci is associated to point mutations in grlA (80,84 and 116) grlB, gyrA (84,88) and gyrB genes. Almost all MRSA strains are ciprofloxacin and levofloxacin resistant while, in a lesser degree, MRCoN staphylococci show to be resistant to levofloxacin. This observation made possible to predict a different correlation between methicillin-resistance and the resistance to FQs in this two different species. In this study, we compare genomic analysis of S. aureus and S. epidermidis with the resistance to FQs. Our results show that strains of MRSA are distributed in 4 different PFGE-types while 12 MRSE strains are distributed in 9. MRSA resistant to FQs showed a unique PFGE pattern; on the contrary of FQs susceptible MRSA and MSSA. Furthermore mecA and gyrA genes are located in the same SmaI fragment in MRSA and in different in MRSE. MSSE and MRSE show more ClaI/mecA polymorphisms than MRSA. All this data confirm the clonal origin of MRSA and show that FQs resistance is linked to the presence of mec locus and both clonally spread. On the contrary in MRSE FQs-resistance is independent from MR and arise with the normal frequence of antibiotic induction.

Anti-Infective Agents↗
PubMed2004

The effect of systemic antibiotics on the microbiological diagnosis of experimental foreign body infections caused by Staphylococcus epidermidis.

Qualitative broth culture and quantitative culture on agar were compared with quantitative polymerase chain reaction (PCR) for the diagnosis of foreign body infections (FBI) in a rat model with and without exposure to systemic antibiotics (teicoplanin and rifampin). The 3 methods had a similar and high yield without antibiotics. Antibiotics decreased the number of CFU/foreign body and increased the number of culture-negative foreign bodies and the variability of the results in quantitative culture. The yield of broth culture remained high under antibiotics although prolonged incubation (2-5 days) was required. The yield of the PCR was equivalent or even superior (for teicoplanin) to the yield of broth culture. Quantitative PCR had a higher yield and lower variability than quantitative culture and was not affected by antibiotics. The simultaneous isolation of RNA from all samples indicated viability of the bacteria. Quantitative PCR seems a promising method for the diagnosis of FBI.

Animals↗
PubMedDate not supplied

[An opsonin-independent strain of Staphylococcus epidermidis].

Human neutrophils, subjected to stimulation under different conditions (phorbol myristate acetate, opsonized zymosan, formylmethionyl-leucinephenylalanine, nonopsonized staphylococci), produced a factor (denoted as clumping factor, or CF) with a capacity for highly selective clumping and opsonization of staphylococci. Out of 68 strains of different species of staphylococci, only a single strains (S.epidermidis) was sensitive of CF. CF negative staphylococci were capable of inducing the release of CF by neutrophils, but were not bound by this factor. Extracts, obtained by the mechanical destruction of neutrophils (sonication, repeated freezing and thawing), had no clumping activity. CF had a mol. wt. exceeding 100 kD, was positively charged and disintegrated at 100 degrees C. The capacity of S.epidermidis 178 M for binding CF completely disappeared after the treatment of bacteria with pronase and partially disappeared after boiling and treatment with trypsin and periodate. Neuraminidase and heating at 80 degrees C produced no effect. These data are the first demonstration of highly selective (strain-specific) interaction between secretory products of neutrophils and bacteria.

Antibodies, Bacterial↗
PubMed1986

Colonization by gentamicin-resistant Staphylococcus epidermidis in a special care baby unit.

Babies entering a special care baby unit during a 3-month period were studied prospectively for colonization by gentamicin-sensitive and -resistant coagulase-negative staphylococci (CNS). Gentamicin-resistant isolates were characterized by biotyping, antibiotic sensitivity pattern and phage-typing. All the babies studied became colonized with gentamicin-resistant CNS and often with multiple strains. Gentamicin-sensitive CNS usually appeared first and predominated, but gentamicin-resistant staphylococci could be detected by enrichment culture at a median time of 1 day, and, by direct culture at a median time of 4 days. Similar strains were found in the environment and nasal carriage was detected in 60% of the staff of the unit by enrichment culture. The gentamicin-resistant strains were all resistant to benzylpenicillin and other antibiotics. No particular pathogenic strain could be identified, but clusters of colonizations by distinguishable strains were noted. Biotype SVI was frequently encountered, particularly among clinically significant isolates.

Anti-Bacterial Agents↗
PubMed1998

Changes in the biocide susceptibility of Staphylococcus epidermidis and Escherichia coli cells associated with rapid attachment to plastic surfaces.

Differences in opacity between wells of a microtitre plate containing different volumes of inoculated growth medium reflected planktonic growth without any contribution from cells attached at the well surface. Simple algebra and a knowledge of the dependence of optical density upon sample path length (volume) for suspensions of differing cell density enables the generation of growth curves for attached populations (biofilms). In this manner, minimum inhibitory concentrations (MICs) were determined at various stages of growth (0-20 h), both for cells growing attached to the bases of the plate wells and, simultaneously, for cells growing in suspension above them. Biocides included cetrimide, polyhexamethylene biguanide, peracetic acid, phenoxyethanol and chloroxylenol. Results, expressed as planktonic:biofilm MIC ratios, showed susceptibility to change, not only as a function of attachment and biofilm formation, but also with respect to the nature of the chemical agent. In some instances, changes in susceptibility greater than twofold occurred immediately on attachment and could occur in the presence of biocide concentrations which exceeded the MIC.

Anti-Infective Agents, Local↗
PubMed1988

Therapeutic considerations for infections caused by Staphylococcus epidermidis.

Most institutions are experiencing increased numbers of methicillin-resistant S. epidermidis infections. Currently, vancomycin is the only antibiotic that provides reliable bactericidal activity against this microorganism, including methicillin-resistant strains. Vancomycin is the treatment of choice for infections caused by methicillin-resistant staphylococci and for serious gram-positive infections in penicillin-allergic patients. With the emergence of more numerous and more serious gram-positive infections, this agent either alone or in combination with other antibiotics will clearly assume greater importance in the management of gram-positive infections, independent of host allergy or bacterial resistance. It is assuming a pivotal role in the treatment of gram-positive infections of central nervous system or dialysis shunts, endocarditis, meningitis, and septicemia. Except in patients with confirmed allergy to a beta-lactam antibiotic, vancomycin is not indicated for routine surgical prophylaxis. The current upsurge in methicillin-resistant staphylococcal infections as a complication of implant surgery may necessitate its use as a prophylactic agent, however.

Adult↗
PubMed1996

Staphylococcus epidermidis adhesion to films deposited from hydroxyethylmethacrylate plasma.

The adhesion of S. epidermidis ATCC 35984 strain on polystyrene (PS) disks coated by films deposited from hydroxyethylmethacrylate (HEMA) plasma was evaluated and compared to adhesion on untreated PS and oxygen-plasma-treated PS. Films were deposited keeping constant the monomer flow rate while the discharge power ranged from 40-100 W in order to obtain coating with different surface properties. Surface chemistry, energetics, and morphology were evaluated by Electron Spectroscopy for Chemical Analysis (ESCA), contact angle measurement, and Atomic Force Microscopy (AFM), respectively. Bacteria adhered more to the plasma-deposited or plasma-treated surfaces than to untreated PS, but no significant difference was recorded among the samples obtained using different deposition conditions. According to the surface energetic analysis, plasma-deposited and plasma-treated surfaces bear a strong Lewis-base character, so it is possible to hypothesize a marked contribution of electron donor-electron acceptor interactions to the mechanism(s) controlling adhesion between synthetic and bacterial surfaces.

Bacterial Adhesion↗
PubMed1985

Anticoagulant properties of extracellular slime substance produced by Staphylococcus epidermidis.

Slime produced by S. epidermidis strain KH 11 was extracted with phenol-saline. The saline phase was fractionated on a DEAE-Sepharose CL-6B column. The crude slime solution and its phenol-saline fraction were found to possess anticoagulant properties. They inhibited the coagulation of human plasma by thrombin, prolonged the activated partial thromboplastin time, but did not change the rate of plasma coagulation by reptilase. The anticoagulant effect of slime could be neutralized by rather high concentrations of protamine sulphate. In the presence of plasma, the staphylococcal slime also inhibited in a concentration dependent fashion the amidolytic activity of thrombin and factor Xa against synthetic chromogenic substrates. Both antithrombin III (AT III) and other plasma component(s), presumably heparin cofactor II, were required for the full expression of the slime effect. The anticoagulant action of slime was markedly less AT III dependent than that of heparin. The activity was resistant to heating (100 degrees C, 30 min). Slime and its fractions were stronger inhibitors of thrombin than of factor Xa. Fraction IV separated by DEAE-Sepharose chromatography and particularly rich in galactose and glucuronic acid had the highest inhibitory potency. It is conceivable that slime component(s) similar to glycosaminoglycans from other sources can carry the anticoagulant activity.

Anticoagulants↗
PubMed1984

Hospital-acquired bloodstream infections with Staphylococcus epidermidis. Review of 100 cases.

During a seven-year study period, 1976 to 1982, this prospective surveillance program detected 108 episodes of nosocomial bacteremia caused by coagulase-negative staphylococci (seven per 10,000 admissions). Chart reviews were subsequently performed in 100 patients primarily to define the patient population and determine outcome of infection. Seventy-two patients had at least two culture bottles that showed growth of coagulase-negative staphylococci plus one or more cultures that showed growth at another site or on a vascular catheter. Most of the patients were in the early or later stages of life: 20 were premature infants, 20 additional infants were under one year of age, and 35 patients were 50 years of age or older. Seventy-three patients were in intensive care areas at the time of the infection. The mortality for the 100 patients studied was 34 percent, with a rate of 9 percent per week after infection. Ninety-three patients had arterial or central lines in place prior to bacteremia and, in 36 reviewed, the mean duration of use of each type of catheter (5.1 days or more) was longer than recommended. In 56 percent of 46 catheters cultured semiquantitatively, there was growth of coagulase-negative staphylococci. The presence of coagulase-negative staphylococci in the blood is associated with significant mortality in hospitalized patients. No longer can their presence in the blood be disregarded as mere contaminants, especially in patients in critical care units.

Adolescent↗
PubMed2001

Quantification of expression of Staphylococcus epidermidis housekeeping genes with Taqman quantitative PCR during in vitro growth and under different conditions.

The aims of the present study were (i) to develop and test a sensitive and reproducible method for the study of gene expression in staphylococci and (ii) to study the expression of five housekeeping genes which are involved in nucleic acid metabolism (gmk, guanylate kinase; the dihydrofolate reductase [DHFR] gene), glucose metabolism (tpi, triosephosphate isomerase), and protein metabolism (the 16S rRNA gene; hsp-60, heat-shock protein 60) during in vitro exponential and stationary growth. A modified method for instant mRNA isolation was combined with gene quantification via Taqman real-time quantitative PCR. The detection limit of our method was 10 copies of RNA. The average intersample variability was 16%. A 10-fold increase in the expression of the hsp-60 gene was induced by exposure to a 10 degrees C heat shock (37 to 47 degrees C) for 10 min. During in vitro growth, the expression of all five housekeeping genes showed rapid up-regulation after inoculation of the bacteria in brain heart infusion medum and started to decline during the mid-exponential-growth phase. Maximal gene expression was 110- to 300-fold higher than gene expression during stationary phase. This indicates that housekeeping metabolism is a very dynamic process that is extremely capable of adapting to different growth conditions. Expression of the 16S rRNA gene decreases significantly earlier than that of other housekeeping genes. This confirms earlier findings for Escherichia coli that a decline in bacterial ribosomal content (measured by 16S rRNA gene expression) precedes the decline in protein synthesis (measured by mRNA expression).

Chaperonin 60↗
PubMed2002

Detection of slime production by means of an optimised Congo red agar plate test based on a colourimetric scale in Staphylococcus epidermidis clinical isolates genotyped for ica locus.

This investigation was conduced on a collection of 113 S. epidermidis strains isolated from biomaterial-associated infections. All strains were examined both for the presence of icaA and icaD genes responsible for slime synthesis by a PCR method and for the in vitro slime production ability by the Congo red agar (CRA) plate test. In the present study, the original CRA test was optimised adopting a six-colour reference scale for a fine classification of colonies colours. The six-colour tones of the scale were as follows: very black (vb), black (b), almost black (ab), which were considered as positive results, and bordeaux (brd), red (r), and very red (vr), interpreted as negative. 57.5% of all the strains were found to be icaA icaD-positive as well as slime-forming onto CRA, exhibiting the following colonies colours: vb (35.4%); b (15.9%); ab (6.2%). The percentage of icaA icaD-negative strains was 42.5% and all of them were negative onto CRA: brd (19.5%), r (14.2%), vr (8.8%). The comparison of colour classification with the information on ica genes confirmed the validity of the scale adopted, providing support to the criteria used for a correct interpretation of the colonies colour during the execution of the CRA test. Overall these results indicate a fine consistency between these two experimental methods and a good reliability of CRA plate test, especially when this is supported by a colourimetric scale.

Biological Assay↗
PubMedDate not supplied

Different pro-inflammatory and immunogenic potentials of Propionibacterium acnes and Staphylococcus epidermidis: implications for chronic inflammatory acne.

INTRODUCTION: Propionibacterium acnes (PA) and Staphyloccocus epidermidis (SE) are two major bacterial strains isolated from acne lesions. Nevertheless, only PA seems to be implicated in the pathogenesis of inflammatory acne vulgaris. Evidence for this, however, remains indirect and the precise role of PA in inflammatory acne is still a matter for conjecture. The aim of this study was to compare some pro-inflammatory and adjuvant properties of PA and SE. MATERIAL/METHODS: To determine some of the pathogenic, immunostimulatory, and pro-inflammatory proper of PA and SE, two experimental models of inflammation were used. In vivo; chronic inflammation was induced by intradermal injection of living bacteria into the ear. In vitro; peritoneal macrophages elicited by the bacteria were examined for their ability to generate reactive oxygen species (ROS), nitric oxide (NO), and cytokines. RESULTS: PA, but not SE, evoked mild local inflammation of infected ears. Macrophages elicited with PA produced more tumor necrosis factor alpha and interleukin IL-12 than those induced with SE, while SE was a stronger inducer of IL-10 production. Both bacteria equally induced the generation of NO and ROS. In contrast, only PA showed adjuvant proper-ties. CONCLUSIONS: The results of these studies indicate that SE, in contrast to PA, does not exert pro-inflammatory properties. Thus it is unlikely that SE may be implicated in the pathogenesis of inflammatory acne vulgaris.

Acne Vulgaris↗