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PubMed1989

Effect of amoxycillin and clavulanic acid, alone and in combination, on human polymorphonuclear leukocyte function against Staphylococcus aureus.

The effect of amoxycillin and clavulanic acid on the interaction in vitro of human polymorphonuclear leukocytes with Staphylococcus aureus was examined. The exposure of a non-penicillinase producing Staphylococcus aureus strain to one-fourth the MIC of amoxycillin or clavulanic acid alone significantly increased the uptake of both unopsonized and opsonized bacteria by human polymorphonuclear leukocytes. This effect was also observed when bacteria were exposed to one-fourth the MIC of different proportions of the combination of amoxycillin and clavulanic acid (4/1, 1/1, 1/8 and 1/32). When a penicillinase-producing Staphylococcus aureus strain was used, only clavulanic acid significantly increased the uptake of unopsonized bacteria. The production of superoxide radicals by human polymorphonuclear leukocytes was impaired only by the presence of high concentrations (100 mg/l) of both clavulanic acid or the combination amoxycillin/clavulanic acid (4/1). At this high concentration, however, amoxycillin/clavulanic acid (4/1) significantly increased the intracellular killing of Staphylococcus aureus.

Amoxicillin↗

PubMed1997

Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients.

From January to December 1994, 752 consecutive patients admitted to intensive care units (ICU) for more than two days were studied prospectively for Staphylococcus aureus colonization and infection. Nasal swabs were obtained at admission and weekly during the ICU stay. At ICU admission 166 patients (22.1%) were Staphylococcus aureus nasal carriers, while 586 were free of nasal colonization. Of the 166 nasal carriers, 163 harbored methicillin-sensitive Staphylococcus aureus (MSSA) and three methicillin-resistant Staphylococcus aureus (MRSA). During the ICU stay 24 of the 586 noncolonized patients became nasal carriers (11 MSSA and 13 MRSA), and one nasal carrier initially colonized by MSSA was reconlonized by MRSA. Staphylococcal infections were documented in 51 (6.8%) of the total 752 patients. After 14 days of ICU stay, the probability of developing staphylococcal infections was significantly higher for those patients who were nasal carriers at ICU admission than for those found to be initially negative (relative risk 59.6, 95% CI 20.37-184.32; p < 0.0001). In patients with ICU-acquired nasal colonization, most infections were documented prior to or at the time of the detection of the nasal colonization; thus, in this group of patients nasal carriage showed a lower predictive value for subsequent Staphylococcus aureus infections that that described classically. Paired isolates of nasal colonizing and clinical strains were studied by pulsed-field gel electrophoresis (PFGE) and mecA polymorphism analysis in 30 patients; identity was demonstrated in all but two patients. The results suggest that, outside the setting of an outbreak of MRSA, the detection of Staphylococcus aureus nasal carriers on admission may be particularly useful in identifying those patients who are at high risk for developing staphylococcal infections during their ICU stay.

Biomarkers↗

PubMed1985

[Staphylococcus aureus in the hemodialysis unit].

In haemodialysis patients Staphylococcus aureus is the most frequent pathogen in infections of vascular access. At the same time, a very high share of these patients (up to 55%) are Staphylococcus aureus carriers. Hygienic measures during puncture of the shunt are highly important for prevention of shunt infection which is most likely endogenous.

Ambulatory Care Facilities↗

PubMed2005

Insights on evolution of virulence and resistance from the complete genome analysis of an early methicillin-resistant Staphylococcus aureus strain and a biofilm-producing methicillin-resistant Staphylococcus epidermidis strain.

Staphylococcus aureus is an opportunistic pathogen and the major causative agent of numerous hospital- and community-acquired infections. Staphylococcus epidermidis has emerged as a causative agent of infections often associated with implanted medical devices. We have sequenced the approximately 2.8-Mb genome of S. aureus COL, an early methicillin-resistant isolate, and the approximately 2.6-Mb genome of S. epidermidis RP62a, a methicillin-resistant biofilm isolate. Comparative analysis of these and other staphylococcal genomes was used to explore the evolution of virulence and resistance between these two species. The S. aureus and S. epidermidis genomes are syntenic throughout their lengths and share a core set of 1,681 open reading frames. Genome islands in nonsyntenic regions are the primary source of variations in pathogenicity and resistance. Gene transfer between staphylococci and low-GC-content gram-positive bacteria appears to have shaped their virulence and resistance profiles. Integrated plasmids in S. epidermidis carry genes encoding resistance to cadmium and species-specific LPXTG surface proteins. A novel genome island encodes multiple phenol-soluble modulins, a potential S. epidermidis virulence factor. S. epidermidis contains the cap operon, encoding the polyglutamate capsule, a major virulence factor in Bacillus anthracis. Additional phenotypic differences are likely the result of single nucleotide polymorphisms, which are most numerous in cell envelope proteins. Overall differences in pathogenicity can be attributed to genome islands in S. aureus which encode enterotoxins, exotoxins, leukocidins, and leukotoxins not found in S. epidermidis.

Biofilms↗

PubMed2001

Long-term infectious complications and their relation to treatment duration in catheter-related Staphylococcus aureus bacteremia.

The optimal duration of treatment for catheter-related Staphylococcus aureus bacteremia is not known. Short courses (< or = 2 weeks) of therapy should be viewed with caution because essential data on late complications, such as osteomyelitis and metastatic abscesses, are lacking. This study represents a retrospective analysis of the data from 49 adult patients hospitalised in the period 1994-1996 (mean age, 57 years; range, 20-90 years; 47% male) and from whom Staphylococcus aureus was cultured concomitantly from peripheral blood and catheter segments. Forty-six venous catheters, two arterial catheters, and one unknown type of catheter were used. Forty-four patients were treated with effective anti-Staphylococcus aureus antibiotics. Twenty patients had a favourable outcome, defined as no complication and no death during 1 year of follow-up, 24 patients had complications, 14 patients died due to attributable mortality, and 5 other patients died of an underlying disease without showing signs or symptoms of a complication. Patients were categorised according to the duration of treatment. There were small differences between a shorter (1-14 days) and a longer (>14 days) course of antibiotics with regard to favourable outcome (41% vs. 33%), complications (48% vs. 53%), attributable death (31% vs. 20%), and death due to underlying disease (41% vs. 33%), respectively. The rates of complications and death were high, but a definite conclusion cannot be drawn because the study was underpowered. More randomised trials are needed, but, until the results of such trials are available, the duration of therapy should not be shortened to less than 14 days.

Adult↗

PubMed2005

Evaluation of six commercial identification kits for the identification of Staphylococcus aureus isolated from bovine mastitis.

AIMS: Comparison of six commercially available in human medicine well-established slide agglutination systems for the identification of Staphylococcus aureus. METHODS AND RESULTS: Slide agglutination tests were compared with the conventional tube coagulase test, biochemical identification and with the molecular identification by polymerase chain reaction (PCR) amplification of species-specific parts of the gene encoding the 23S RNA. Systems evaluated included Masta-Staph (Mast Diagnostics), Staphylase-Test (Oxoid), Staphytect-Plus (Oxoid), Staphyloslide Latex (Becton Dickinson), Slidex Staph Plus (bioMerieux) and Dry Spot Staphytect Plus (Oxoid). A total of 141 staphylococcal strains isolated from cases of bovine mastitis including 90 S. aureus, 14 Staphylococcus epidermidis, 10 Staphylococcus warneri, 13 Staphylococcus xylosus, 11 Staphylococcus haemolyticus and three other coagulase-negative staphylococci were tested with each method. Staphylococcus aureus strains were selected by macrorestriction analysis with pulsed field gel electrophoresis (PFGE). Only genetically unrelated strains were included in the study. The sensitivities and specificities of the test were as follows: Masta-Staph 86.7 and 90.1%, Staphylase-Test 78.4 and 85.1%, Staphytect-Plus 81.1 and 86.5%, Staphyloslide Latex 77.8 and 84.4%, Slidex Staph Plus 77.8 and 84.4%, Dry Spot Staphytect Plus 75.6 and 83.0%. CONCLUSIONS: The results of this evaluation suggest that the six slide agglutination methods tested can provide rapid identification of S. aureus also from bovine mastitis. The sensitivity and specificity seems to be less than those reported from human S. aureus isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: This is one of the first comparative reported investigations about the applicability of different commercially available slide agglutination tests for the detection of S. aureus from bovine mastitis using PFGE selected clinical isolates.

Animals↗

PubMed2005

Comparison of genotypes of methicillin-resistant and methicillin-sensitive Staphylococcus aureus in Finland.

The frequency of horizontal transfer of the staphylococcal cassette chromosome mec to methicillin-susceptible Staphylococcus aureus is unknown. In order to gain more information regarding this frequency in Finland, the genotypes of 299 clinical methicillin-sensitive Staphylococcus aureus isolates were compared to representatives of 24 epidemic methicillin-resistant Staphylococcus aureus genotypes. Sixty-eight percent of the methicillin-sensitive isolates had a genotype similar to eight of the epidemic methicillin-resistant strains. The remaining isolates (32%) showed 22 different genotypes. The results indicate that, in Finland, several methicillin-sensitive Staphylococcus aureus genotypes may have acquired the staphylococcal cassette chromosome mec.

Finland↗

PubMed1999

Staphylococcus aureus adherence to nasal epithelial cells in a physiological in vitro model.

Nasal carriage of Staphylococcus aureus represents a risk factor for subsequent invasive infections and interpatient transmission of strains. No physiological in vitro model of nasal epithelial cells is available to study both patient- and bacteria-related characteristics and their interaction, leading to adherence and colonization. Starting with tissues from human nasal polyps, a confluent, squamous, nonkeratinized epithelium in collagen-coated 96-well microtiter plates was obtained after 14 d. This in vitro cell-layer was characterized histologically, ultrastructurally, and immunohistochemically and showed features that were indistinguishable from those observed in the squamous nonkeratinized epithelium found in the posterior part of the vestibulum nasi. Adherence experiments were performed with four different 3H-thymidine-labeled Staphylococcus aureus strains. The effect of bacterial inoculum size, temperature of incubation, and incubation medium were studied. The adherence results were found to be reproducible, reliable and sensitive, allowing detection of small quantitative differences in adherence between the Staphylococcus aureus strains. There was no significant difference in adherence at 23 degrees C and 37 degrees C, nor between the incubation medium M199 and phosphate-buffered saline. Plastic adherence could be reduced and standardized with use of siliconized tips and a constant bacterial inoculum volume of 100 microl/well. This physiological and reliable in vitro cell-culture model offers a unique opportunity to study Staphylococcus aureus adherence to squamous, nonkeratinized nasal epithelial cells and both patient and bacterial characteristics involved in this interaction.

Bacterial Adhesion↗

PubMed2002

Risk factors for nasal carriage of Staphylococcus aureus in infectious disease patients, including patients infected with HIV, and molecular typing of colonizing strains.

Nasal carriage is an important risk factor for Staphylococcus aureus infection, particularly in HIV-infected individuals. In this analytical cross-sectional study, a variety of probable risk factors associated with nasal carriage of Staphylococcus aureus were investigated. HIV-infected patients were examined within a larger cohort of infectious diseases patients. Staphylococcus aureus strains from HIV-infected and non-HIV-infected carriers were identified by molecular biological analysis. One hundred seventy infectious disease patients, 47 of them infected with HIV, were included. All patients were admitted to the University Hospital of Vienna, Austria, between January and July 1999. Independent significant effects on Staphylococcus aureus nasal carriage were found to be HIV status (OR 2.5, 95% CI 1.1-5.6; P=0.0303), history of operation or severe wound within 3 months prior to admission (OR 4.0, 95% CI 1.3-13.0; P=0.0208), presence of an intravenous device within 2 weeks prior to admission (OR 10.8, 95% CI 2.0-59.4; P=0.0065), and intake of antibiotics within 2 weeks prior to hospitalisation (OR 0.2, 95% CI 0.09-0.6; P=0.0016). Molecular analysis of the Staphylococcus aureus strains revealed that the strains in both groups resembled those of healthy nonhospitalized carriers in the community.

AIDS-Related Opportunistic Infections↗

PubMed1998

Limited effectiveness of chlorhexidine based hand disinfectants against methicillin-resistant Staphylococcus aureus (MRSA).

Hand disinfectants containing chlorhexidine are thought to be less bactericidal against methicillin-resistant Staphylococcus aureus (MRSA) than methicillin-susceptible Staphylococcus aureus (MSSA). We report an in vitro comparison between three distinct MRSA strains and three MSSA strains. The bactericidal efficacy of chlorhexidine digluconate, 'Hibiscrub' and 'Hibisol' against Staphylococcus aureus was determined in a quantitative suspension test. Logarithmic reduction factors (RF) were calculated for each of six parallel experiments. Chlorhexidine digluconate and 'Hibisol' showed RF > 5 at most concentrations and reaction times but 'Hibiscrub' did not. MRSA was found to be significantly less susceptible than MSSA to chlorhexidine digluconate, 'Hibiscrub' and 'Hibisol' (P < 0.05; two-tailed t-test for independent samples). 'Hibisol' was significantly more effective against MRSA than 'Hibiscrub' (P < 0.05). Hand disinfectants containing both alcohol and chlorhexidine (e.g., 'Hibisol') are more effective against MRSA than scrubs based only on chlorhexidine ('Hibiscrub') and should be used in clinical practice.

Chlorhexidine↗

PubMed2003

[Use of nasal mupirocin for Staphylococcus aureus: effect on nasal carriers and nosocomial infections].

Staphylococcus aureus is the agent of community-acquired and nosocomial infections. Twenty to 35% of the population permanently carries it in the nose and oropharynx, and additional 50%, carries it intermittently. Topical calcium mupirocin is an antibacterial agent against Staphylococcus aureus recommended to eradicate nasal and hand colonization in patients and health care workers. The prevalence of nasal S. aureus was determined in patients undergoing cardiovascular surgery. In addition, the effect of mupirocine on the number of carriers and rate of nosocomial infections was evaluated. An experimental prospective study was undertaken with two groups of patients: one treated with mupirocin (n = 96), and the other without treatment (n = 95). Tests for presence of nasal S. aureus and nosocomial infections were conducted in all patients. A 34% prevalence of S. aureus carriers was found. A decrease of the prevalence was found in both treated (87%) and untreated patients (33%), but in significantly different proportions (p = 0.0002, RR = 0.22, 95%CI = 0.09-0.054). This result demonstrated the effectiveness of a mupirocin treatment program to decrease numbers of nasal carriers. With regard to nosocomial infection, S. aureus prevalence was 3.6%, occurring mostly in control patients (6 of 7). Total nosocomial infection prevalence was 17.3%, evenly distributed in treated and untreated patients. This suggested that mupirocin use did not decrease the number of nosocomial infections.

Administration, Intranasal↗

PubMed2001

Effect of iron limitation on slime production by Staphylococcus aureus.

The aim of this study was to examine the effect of growth conditions on slime production by Staphylococcus aureus clinical isolates. The addition of glucose to the medium enhanced slime production in the majority of Staphylococcus aureus isolates cultured from infections associated with orthopaedic prostheses. Iron limitation also stimulated this ability even in the absence of the additional carbohydrate source. Staphylococcus aureus isolates were classified as Group 1 [strains producing slime only in trypticase soy broth supplemented with 1% glucose (TSBG) or in iron-limited trypticase soy broth (TSB/Fe-)]; Group 2 (slime + only in TSB/Fe-); or Group 3 (slime+ only in TSBG). Seven repeatedly slime-negative strains were stimulated to produce slime by subpassaging in iron-limited medium. Low iron levels, usually found in vivo, could stimulate slime production by Staphylococcus aureus and support chronic infections associated with orthopaedic prostheses.

Bacterial Proteins↗

PubMedDate not supplied

Persistent wound infection after herniotomy associated with small-colony variants of Staphylococcus aureus.

A small-colony variant (SCV) of Staphylococcus aureus was cultured from a patient with a persistent wound infection (abscess and fistula) 13 months after herniotomy. The strain was nonhemolytic, nonpigmented and grew only anaerobically on Schaedler agar. As it was coagulase-negative, it was initially misidentified as a coagulase-negative Staphylococcus. In further analysis, however, the microorganism was shown to be an auxotroph that reverted to normal growth and morphology in the presence of menadione and hemin (Schaedler agar) and could be identified as a SCV of Staphylococcus aureus. Surgery and antibiotic treatment of the patient with flucloxacillin and rifampicin for 4 weeks resulted in healing of the chronic wound infection.

Abdominal Abscess↗

PubMed1980

Radioimmunoassay of thyrotropin and thyroxine in dried blood by use of Staphylococcus aureus containing "protein A.".

We report the use of Staphylococcus aureus rich in protein A as an immunoadsorbent in the radioimmunoassay of thyrotropin and thyroxine in blood collected from newborn infants and dried on filter paper. The procedures for thyrotropin and thyroxine, which differ mainly with respect to concentration and volume of the Staphylococcus aureus suspension, are reliable, rapid, and technically simple. The ease of this method, coupled with its dependability, offers certain advantages over some of the commonly used techniques of separation, and therefore it provides a unique approach to measurement of these analytes in laboratory screening programs for neonatal hypothyroidism.

Blood Specimen Collection↗

PubMed2003

Staphylococcus aureus carriage in selected communities and their antibiotic susceptibility patterns.

The carriage and antibiotic susceptibility patterns of Staphylococcus aureus in the community were determined. Nasal, throat and axillary swabs were taken from 100 healthy adults and 90 disabled nursing home inmates. Antibiotic disc susceptibility testing was conducted following the NCCLS method. Staphylococcus aureus carriage was noted in 29% of healthy adults and 47.7% of nursing home inmates. Out of 79 strains, resistance to antibiotics were as follows; penicillin (92.4%), genetamicin (2.5%), tetracycline (6.3%), fusidic acid (11.3%), erythromycin (3.8%), pefloxacin (5.1%), mupirocin (3.8%), amikacin (3.8%), ciprofloxacin (2.5%) and chloramphenicol (2.5%). Methicillin-resistant Staphylococcus aureus was not isolated. Multiple colonizations and multi-antibiotic resistant Staphylococcus aureus were shown to occur in healthy individuals without risk factors and not previously hospitalized.

Adult↗

PubMed1992

Activity of cefpirome combined with beta-lactamase inhibitors and affinity for the penicillin-binding proteins of methicillin-resistant Staphylococcus aureus.

The susceptibility of 47 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) to cefpirome, ceftazidime and methicillin was determined with Isosensitest media, with/without 5% NaCl and incubation at 30 degrees, 37 degrees and 44 degrees C for 24 and 48 h. At 24 h the MIC50 of cefpirome was 8 mg/l compared to 64 mg/l ceftazidime; at 48 h this increased to 32 mg/l cefpirome. The addition of 10 mg/l clavulanic acid or sulbactam lowered the MIC of cefpirome (at 48 h) by greater than four-fold in 23% and 11% of the strains, respectively. Cefpirome had primary affinity for penicillin-binding protein (PBP) 1 and 2 in five MRSA and one methicillin-susceptible Staphylococcus aureus. PBP 2a was present in all MRSA and was not saturated by 64 mg/l cefpirome. Clavulanic acid at a concentration of 10 mg/l bound to PBP 2 by greater than 50% in all strains, and when combined with cefpirome, the density of PBP 2a was also reduced but not completely abolished. The data from this study suggests that the mechanism of synergy of a beta-lactamase inhibitor plus a cephalosporin for MRSA may be due to an additive effect against PBPs and not just inhibition of a beta-lactamase. No cefpirome-resistant mutants could be selected from a methicillin-susceptible Staphylococcus aureus, but mutants were selected from an MRSA (expressing homogeneous methicillin resistance) for which MICs of cefpirome were 8 to 32 mg/l.

Bacterial Proteins↗

PubMed2004

Emergence of methicillin resistant Staphylococcus aureus (MRSA) bacteraemia among children in England and Wales, 1990-2001.

Methicillin resistant Staphylococcus aureus (MRSA) is now a major cause of adult bacteraemia. All reports of Staphylococcus aureus bacteraemia to the Health Protection Agency were analysed from 1990 to 2001. There were 376 cases of MRSA bacteraemia in children <15 years over this time. The proportion of Staphylococcus aureus bacteraemia due to MRSA increased steadily from 0.9% in 1990 to 13% in 2000. The proportion was higher in infants. MRSA bacteraemia is now a serious problem in children in England and Wales. More data on the risk factors for acquisition and spread of MRSA in children are required.

Adolescent↗

PubMed1980

Virulence of three strains of Staphylococcus aureus isolated from clinically infected bovine mammary glands.

Factors in the ability of three strains of Staphylococcus aureus to cause bovine mastitis were studied. Each strain was evaluated fro growth rate, clump size, and resistance to phagocytosis and intracellular kill by polymorphonuclear leukocytes isolated from milk of nine cows. Variation among cows in the ability of polymorphonuclear leukocytes to phagocytose and of skim milk to support phagocytosis was assessed. Virulent strains of Staphylococcus aureus had a smaller clump size (1.5 colony forming units [CFU]/clump) than the less virulent strain (2.6 CFU/clump) after 180 min of growth in skim milk samples. When the skim milk samples were sonicated to disperse the staphylococci, population density of strains of Staphylococcus aureus did not differ. Phagocytosis and total number of staphylococci killed by polymorphonuclear leukocytes were depressed for virulent strains. Ability of polymorphonuclear leukocytes isolated from individual cows to phagocytose each strain of Staphylococcus aureus varied. The correlation with treated cases of clinical mastitis per lactation was -.54. The ability of skim milk to support phagocytosis by polymorphonuclear leukocytes also differed among cows. The correlation with treated cases of clinical mastitis per lactation was -.51.

Animals↗