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PubMed1976

Epidemiologic application of a typing method for Staphylococcus epidermidis strains by the serum-soft agar technic.

Using the serum-soft agar technic of Staphylococcus epidermidis typing, an epidemiologic study of pollution with S. epidermidis in the tuberculosis and pediatric wards of a hospital was conducted. Specimen samples were taken from 334 locations, including beds, bedspreads, pillows, doors and window knobs, chairs, tables, and incubators of premature infants. These were cultured on Staphylococcus 110 medium and the strains identified as S. epidermidis were obtained. Of the strains from both patients' rooms and the nurses' station in the tuberculosis ward a considerable number were of serotype 53, suggesting an interrelationship of this organism and these locations. In the rooms of newborns and premature infants in the pediatric ward, 55.5% of the strains of S. epidermidis isolated were of the serotype 53/408, indicating a high degree of pollution of these environments with these serotype strains.

Agar↗

PubMed1998

Mechanism of salicylate-mediated inhibition of biofilm in Staphylococcus epidermidis.

The inclusion of 5 mM salicylic acid (SAL) in medium inhibited both growth and biofilm production by Staphylococcus epidermidis by up to 55%. The inhibition was not due primarily to chelation of cations. Excess divalent cations restored growth and biofilm production in chelated medium and in medium containing EDTA but not in medium containing SAL. ELISA analyses demonstrated that SAL inhibited production of teichoic acid, slime-associated proteins, and type 1 antigen by as much as 95%. However, it inhibited polysaccharide/adhesin production by only 50%--a figure paralleling the reduction in growth. The equivalent inhibitory effects of SAL on a pair of isogenic strains, one of which was a polysaccharide/adhesin-deficient mutant, confirmed that the primary effect of SAL was a reduction in the production of biofilm components rather than a reduction in the retention of these components in the slime layer prior to assembly into a biofilm.

Adhesins, Bacterial↗

PubMed1987

Immunostimulating cell surface substance from Staphylococcus epidermidis strain ATCC-31432 prevents metastatic lung colonization in Balb/c-mice.

The antineoplastic activity of cell surface substance from Staphylococcus epidermidis ATCC-31432 (CSS-subfraction 2) in mice and its influence on the activation of human leucocytes was studied. After in vitro incubation with CSS-subfraction 2, human polymorphonuclear leucocytes were evidently stimulated. In vivo (Balb/c-mice) intraperitoneal application of subfraction 2 of CSS induced a considerable splenomegaly and greatly increased IgM levels indicating a strong immuno-stimulating activity. In order to evaluate antineoplastic effects of CSS-subfraction 2, we used sarcoma L-1 cells (Balb/c-mouse origin) which cause heavy tumor colonization of the lung. After single systemic injection of subfraction 2 of CSS, the number of lung tumor-cell colonies drastically decreased. The combination of this immunomodulating therapy with a temporary anticoagulation resulted in a further reduction of tumor colonies in the lungs of Balb/c-mice.

Adjuvants, Immunologic↗

PubMed2000

Molecular epidemiology of Staphylococcus epidermidis in a neonatal intensive care unit over a three-year period.

Coagulase-negative staphylococci, especially Staphylococcus epidermidis, are increasingly important nosocomial pathogens, particularly in critically ill neonates. A 3-year prospective surveillance of nosocomial infections in a neonatal intensive care unit (NICU) was performed by traditional epidemiologic methods as well as molecular typing of microorganisms. The aims of the study were (i) to quantify the impact of S. epidermidis on NICU-acquired infections, (ii) to establish if these infections are caused by endemic clones or by incidentally occurring bacterial strains of this ubiquitous species, (iii) to evaluate the use of different methods for the epidemiologic typing of the isolates, and (iv) to characterize the occurrence and the spread of staphylococci with decreased glycopeptide susceptibility. Results confirmed that S. epidermidis is one of the leading causes of NICU-acquired infections and that the reduced glycopeptide susceptibility, if investigated by appropriate detection methods such as population analysis, is more common than is currently realized. Typing of isolates, which can be performed effectively through molecular techniques such as pulsed-field gel electrophoresis but not through antibiograms, showed that many of these infections are due to clonal dissemination and, thus, are potentially preventable by strict adherence to recommended infection control practices and the implementation of programs aimed toward the reduction of the unnecessary use of antibiotics. These strategies are also likely to have a significant impact on the frequency of the reduced susceptibility of staphylococci to glycopeptides, since this phenomenon appears to be determined either by more resistant clones transmitted from patient to patient or, to a lesser extent, by strains that become more resistant as a result of antibiotic pressure.

Birth Weight↗

PubMed1995

Revised interpretation of oxacillin MICs for Staphylococcus epidermidis based on mecA detection.

In 1992 and 1993, at The Ohio State University Medical Center, a larger proportion of Staphylococcus epidermidis strains required oxacillin MICs of 1 to 2 micrograms/ml than did Staphylococcus aureus strains. mecA genotype was correlated with antimicrobial susceptibility for selected clinical S. epidermidis strains. All 14 strains that required oxacillin MICs of < or = 0.25 microgram/ml and 2 of 5 strains that required oxacillin MICs of 0.5 microgram/ml were susceptible by 1-microgram oxacillin disk test and were mecA negative. Three of 5 strains that required oxacillin MICs of 0.5 microgram/ml and all 18 strains that required oxacillin MICs of > or = 1.0 microgram/ml were resistant by oxacillin disk test and were mecA positive. Current National Committee for Clinical Laboratory Standards MIC interpretive criteria may underestimate methicillin resistance among S. epidermidis strains.

Bacterial Proteins↗

PubMedDate not supplied

Intravitreal trovafloxacin against experimental Staphylococcus epidermidis endophthalmitis.

This study was designed to test the effects of intravitreal trovafloxacin on an experimental rabbit model of Staphylococcus epidermidis endophthalmitis. Out of 26 rabbits, 22 were given intravitreal S. epidermidis (100,000 CFU). At 24 h, group 1 (8 rabbits) and, at 48 h, group 2 (8 rabbits) received 100 microg intravitreal trovafloxacin. Group 3 (6 rabbits) was used as inoculated but untreated controls. Four rabbits (group 4) were used as uninfected controls. Clinical scores were calculated at 24, 48 and 72 h. Microbiological and histopathological scorings were made. Microbiological analysis showed that trovafloxacin administered at 24 or 48 h significantly reduced the number of bacteria compared to the untreated group. We conclude that trovafloxacin applied at 24 or 48 h is effective against S. epidermidis endophthalmitis in this experimental rabbit model.

Animals↗

PubMed1994

Early adhesion of bacteremic strains of Staphylococcus epidermidis to polystyrene: influence of hydrophobicity, slime production, plasma, albumin, fibrinogen, and fibronectin.

Twenty bacteremic strains of Staphylococcus epidermidis were characterized according to their hydrophobicity, their ability to produce slime, and their in vitro adhesion to polystyrene microtiter plates precoated or not with plasma proteins. Four strains of Staphylococcus aureus were also tested for adhesion. Slime production in S. epidermidis was not correlated with initial adhesion, whether measured qualitatively or by a quantitative method. Hydrophobicity (xylene:water partition) was well correlated with adhesion. Slime production, adhesion, and hydrophobicity were highly strain dependent among S. epidermidis organisms. For S. epidermidis, early adhesion was inhibited (10% to 98%) by albumin and fibronectin in all strains, by plasma (19 strains), and by fibrinogen (18 strains). Stimulation occurred for one strain with plasma and two strains with fibrinogen. In contrast, adhesion was inhibited by albumin and markedly stimulated (twofold to 14-fold) by plasma, fibrinogen, and fibronectin for the four strains of S. aureus. Early adhesion of S. epidermidis to polymer surface appears to depend mainly on hydrophobicity and is usually impaired by plasma proteins, albumin, fibrinogen and fibronectin; with a heterogeneous behavior among the different strains tested. Slime production would interpose secondarily, after the first attachment.

Bacterial Adhesion↗

PubMed1994

Staphylococcus epidermidis as a cause of urinary tract infections in children.

We describe two otherwise healthy children with pyelonephritis caused by Staphylococcus epidermidis. We conclude that S. epidermidis can be a urinary tract pathogen in children without indwelling catheters or other obvious medical problems. Physicians should not automatically assume that S. epidermidis is a contaminant in urine cultures.

Acute Disease↗

PubMed1994

Iron chelator, exopolysaccharide and protease production in Staphylococcus epidermidis: a comparative study of the effects of specific growth rate in biofilm and planktonic culture.

The growth rate of Staphylococcus epidermidis was controlled for populations growing as a biofilm and perfused with supplemented, simple-salts medium. Production of iron chelators, extracellular protease and exopolysaccharide (EPS) by these populations was assessed as a function of specific growth rate and compared to that by planktonic populations grown in the same medium within a chemostat. Perfused biofilms increased their iron chelator and protease production with increasing growth rate. Chemostat populations decreased their production of iron chelators with increasing growth rate, whilst showing much enhanced production of proteases at intermediate growth rates (mu 0.15-0.25 h-1). Production of iron chelator and protease was generally 2-50 times higher by biofilms than by planktonic populations. EPS production was low and relatively unaffected by growth rate for the chemostat cultures (about 0.2 micrograms per unit cell mass) but high for the attached biofilms, particularly at slow growth rates (about 4 micrograms per unit cell mass). EPS production within the biofilms decreased markedly with increasing growth rate. At growth rates of 0.35 h-1 and above, the levels of EPS for biofilms and planktonic populations were equivalent. The results of this study clearly indicate that growth as a biofilm markedly influences extracellular virulence factor production by S. epidermidis.

Animals↗

PubMed1984

Staphylococcus epidermidis bacteremia associated with vascular catheters: an important cause of febrile morbidity in hospitalized patients.

Seventeen episodes of persistent Staphylococcus epidermidis bacteremia (one to nine days) occurred in 16 patients with vascular catheters during a 26-month period. Cases were statistically more likely to have a longer hospitalization (54 v 7.6 days, p less than .0005), longer duration of antibiotic therapy (22 v 2.5 days, p = .002), presence of a central venous pressure (CVP) catheter (14 v 2, p less than 3 X 10(-8), and presence of an arterial catheter (4 v 1, p = 0.037) than randomly selected hospitalized patients matched for age, sex, and date of admission. However, when cases were compared with similarly matched non-bacteremic patients having CVP catheters, these characteristics were not significantly different in the two groups. Furthermore, exposure to total parenteral nutrition (TPN) and duration of TPN were not significantly different between cases and controls. Hence, the presence of a CVP catheter appeared to be the major risk factor for S. epidermidis bacteremia. In 16 episodes, patients had temperature greater than 38.6 degrees C without another identifiable cause, and the average white cell count for the case group was 19,400/mm.3 Seven patients also had diaphoresis, confusion, hypotension, or oliguria. Temperatures returned to normal in 13 within 24 hours after catheter removal, and all patients were afebrile and symptom-free within 72 hours. Thus, vascular catheter-associated S. epidermidis bacteremia was an important case of febrile morbidity in these patients.

Adolescent↗

PubMed1995

Persistence of a multiresistant clone of Staphylococcus epidermidis in a neonatal intensive-care unit for a four-year period.

A cluster of cases of Staphylococcus epidermidis bacteremia in a neonatal intensive-care unit (NICU) during 1991 raised the question of whether these infections were caused by a single strain. Sixty-seven isolates of S. epidermidis from blood cultures of 56 neonates treated in the NICU between 1986 and 1992 and 54 control strains from other patients with bacteremia were characterized by three typing methods: antibiogram, plasmid profile, and ribotype. Plasmid profiles and ribotype patterns indicated that 11 (16%) of the 67 episodes of S. epidermidis bacteremia in the NICU were caused by a single strain. Although this epidemic strain did not account entirely for the increase in the incidence of bacteremia in the NICU, it did persist for 4 years during the study period. Other clones responsible for smaller outbreaks were also found. These results suggest that S. epidermidis cross-infections are very common in the NICU setting.

Bacteremia↗

PubMed2001

Comparative evaluation of hydrophobicity measures for virulence determination of Staphylococcus epidermidis from hospitalized patients & healthy individuals.

BACKGROUND & OBJECTIVES: Hydrophobicity is one of the recognized markers for identifying pathogenic strains of Staphylococcus epidermidis. A number of tests are available for measuring the hydrophobic character but three tests viz., salt aggregation test (SAT), n-hexadecane adherence assay (HAA) and xylene adherence assay (XAA) are in common practice with different degrees of sensitivity. However, in the Indian context, no systematic study has been reported on the hydrophobicity of S. epidermidis. Hence, the present study was undertaken to compare the three methods for hydrophobicity measurement for identifying the pathogenic isolates of S. epidermidis. METHODS: Of the 597 samples obtained from milker's and butcher's (hand and nose), hospitalized pre-operative patients (hand, nose, ear), and post-operative patients (blood) examined, 212 isolates of S. epidermidis were recovered using established laboratory procedures. The isolates were screened by the three tests viz., SAT, HAA and XAA. The identified hydrophobic isolates were further tested by mouse inoculation method. RESULTS: Of the 212 S. epidermidis isolates studied, 24 (11.32%), 23 (10.84%) and 4 (1.88%) were found to be hydrophobic as detected by HAA, XAA and SAT, respectively. No isolates from apparently healthy individuals were found to be hydrophobic by SAT while 13 (8.76%) and 10 (8.24%) strains from apparently healthy individuals were detected to be hydrophobic by HAA and XAA, respectively. Seven (33.38%) isolates each were hydrophobic by HAA and XAA and 4 (22.22%) by SAT among the isolates from hospitalized post-operative patients. INTERPRETATION & CONCLUSION: The results suggested that there was no difference in the number of strains detected as hydrophobic by HAA and XAA, and any of the two tests may be used for screening the hydrophobic strains of S. epidermidis from healthy individuals and patients.

Bacteriological Techniques↗

PubMed1995

Synergy between protamine and vancomycin in the treatment of Staphylococcus epidermidis biofilms.

OBJECTIVES: To test for synergy between protamine and vancomycin by analyzing their bactericidal activities against slime-producing Staphylococcus epidermidis ATCC 35983 under planktonic and biofilm conditions. METHODS: We evaluated the activity of vancomycin and protamine separately against planktonic S epidermidis in broth by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each agent according to the standard macrobroth dilution method. To assess the possibility of synergy between these two agents, planktonic S epidermidis was exposed to vancomycin and protamine together in varying concentrations. Biofilms containing S epidermidis were then prepared and subjected to incubation with vancomycin and protamine separately as well as combined in varying concentrations. The bacterial viability of S epidermidis in the planktonic and biofilm phases after exposure to these two agents was assessed by qualitative culture and determination of viable colony blots. RESULTS: Standard antibacterial susceptibility tests revealed that the MICs of protamine and vancomycin were 1 and 2 micrograms/mL, respectively, and their MBCs were 4 micrograms/mL. The MICs were unchanged when protamine and vancomycin were combined in varying concentrations. Neither agent exhibited significant bactericidal activity against S epidermidis in the biofilm phase at concentrations < or = 32 micrograms/mL. However, a combination of both agents, each at 32 micrograms/mL, resulted in a 7-log decrease in viable bacterial counts. CONCLUSIONS: Protamine alone exhibited significant antibacterial activity against planktonic S epidermidis. No synergy was noted between protamine and vancomycin against S epidermidis in the planktonic phase. However, synergy was demonstrated when a combination of protamine and vancomycin was used on S epidermidis in the biofilm phase. Thus, protamine shows promise as an adjunctive agent to vancomycin in the treatment of S epidermidis in biofilms.

Biofilms↗

PubMed1996

In vitro activities of oxazolidinone compounds U100592 and U100766 against Staphylococcus aureus and Staphylococcus epidermidis.

The new oxazolidinone antimicrobial agents U100592 and U100766 demonstrated good in vitro inhibitory activity against clinical strains of Staphylococcus aureus and Staphylococcus epidermidis regardless of methicillin susceptibility. Both agents appeared bacteriostatic by time-kill analysis. Stable resistance to low multiples of the MIC of either drug could be produced only in methicillin-resistant S. aureus.

Acetamides↗

PubMed2006

Peri-implant tissue is an important niche for Staphylococcus epidermidis in experimental biomaterial-associated infection in mice.

Biomaterial-associated infections (BAI), which are predominantly caused by Staphylococcus epidermidis, are a significant problem in modern medicine. Biofilm formation is considered the pivotal element in the pathogenesis, but in previous mouse studies we retrieved S. epidermidis from peri-implant tissue. To assess the kinetics and generality of tissue colonization, we investigated BAI using two S. epidermidis strains, two biomaterials, and two mouse strains. With small inocula all implants were culture negative, whereas surrounding tissues were positive. When higher doses were used, tissues were culture positive more often than implants, with higher numbers of CFU. This was true for the different biomaterials tested, for both S. epidermidis strains, at different times, and for both mouse strains. S. epidermidis colocalized with host cells at a distance that was >10 cell layers from the biomaterial-tissue interface. We concluded that in mouse experimental BAI S. epidermidis peri-implant tissue colonization is more important than biofilm formation.

Animals↗

PubMed1986

Staphylococcus epidermidis in diabetic urological patient.

We present 6 patients in whom prosthetic failure occurred because of sepsis owing to Staphylococcus epidermidis. Such failure occurs in grafts in other areas and is caused by the high resistance of the organism to conventional antibacterial measures. Therapy with appropriate antibiotics, that is aminoglycosides, vancomycin and rifampin, and the need for an early operation are stressed.

Adult↗

PubMed1992

Role of the Staphylococcus epidermidis slime layer in experimental tunnel tract infections.

An experimental animal model was used to assess the slime layer of Staphylococcus epidermidis as a pathogenic factor in tunnel tract infections. Mice were inoculated with high-slime-producing or non-slime-producing strains of S. epidermidis, either along the length of a subcutaneous catheter or in the area where a catheter had been placed and immediately removed (controls). Among the catheter-bearing mice, the phenotypically distinct staphylococci produced similar, high frequencies of abscess formation (72% [44 of 61] versus 81% [31 of 38]; P = 0.29). In controls, the non-slime-producing organisms were significantly more pathogenic (87% [40 of 46] versus 57% [25 of 44] abscess formation; P = 0.001). No consistent difference was detected between blood isolates obtained from patients with central venous catheter bacteremia and those from neonates with bacteremia in the absence of a prosthetic medical device. Quantitative culture of removed catheters showed greater adherence by the slime-producing isolates (P = 0.014). In this mouse model, slime production by S. epidermidis did not increase the risk of catheter tunnel tract infection, despite the greater catheter adherence of the slime-producing organisms. These findings suggest that traumatized tissue may be a sufficient condition for the development of S. epidermidis catheter-associated infections.

Abscess↗

PubMed2003

Bacterial adherence of Staphylococcus epidermidis to intraocular lenses: a bioluminescence and scanning electron microscopy study.

PURPOSE: To analyze and compare the adherence of Staphylococcus epidermidis to intraocular lenses (IOLs) made of five different biomaterials (native or heparinized polymethylmethacrylate, silicone, hydrophilic acrylic, or hydrogel) and to detail the different steps and mechanisms of bacterial adhesion to a polymer. METHODS: A clinical strain carrying the intercellular adhesion (ica) locus was used. In a previous study, the extent of bacterial binding was measured by counting. In this study, two different techniques, bioluminescence and scanning electron microscopy (SEM), were used to analyze the accuracy of each one, to obtain a comparison between the various IOLs, and to complete previous observations. The results were compared using both the Kruskal-Wallis and the Mann-Whitney nonparametric tests. RESULTS: Bacterial adhesion was statistically weakest on hydrogel and then on hydrophilic acrylic polymer. Adhesion depended on the hydrophobicity or hydrophilicity of the biomaterials. Slight differences were found between the two methods, and these differences are explained. Furthermore, SEM observations highlighted two different patterns of bacterial adhesion (isolated bacteria and clusters of bacteria), assuming that hydrophobic IOLs (silicone and PMMA) probably facilitate bacterial colonization and biofilm production. CONCLUSIONS: Attachment mechanisms may be different in each case, depending on the polymer material and the infecting organism, because there are various types of behavior among S. epidermidis strains. Hydrophilic polymer surfaces (hydrogel and probably hydrophilic acrylic) seem to be useful in avoiding the development of bacterial colonies and hence in preventing endophthalmitis. Fewer bacteria were attached, demonstrating inhibition or delay in bacterial colonization.

Acrylic Resins↗