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PubMed2000

Staphylococcus aureus bacteremia and endocarditis.

Staphylococcus aureus bacteremia is a serious and common disease often associated with infective endocarditis. It occurs in both healthy, immunologically competent people in the community and compromised patients in the hospitals. For S. aureus bacteremia, questions on clinical issues such as antimicrobial treatment are raised. Is nafcillin/oxacillin superior to vancomycin? Does the addition of rifampin improve outcome? Does addition of aminoglycoside improve the outcome? Does increasing duration of therapy (> 4 weeks versus < 2 weeks) improve outcome? How many cases of community-acquired S. aureus bacteremia have endocarditis on admission? What are the risk factors that would separate bacteremia from endocarditis? What is the role of echocardiography? What are the indications for routine echocardiography? Are methicillin-resistant S. aureus (MRSA) more virulent than methicillin-susceptible S. aureus (MSSA)? What factors predict mortality in S. aureus bacteremia? Herein, the above important issues on S. aureus bacteremia and endocarditis are critically reviewed.

Animals↗

PubMed1991

[Efficacy evaluation of cloxacillin and cloxacillin-gentamicin in an experimental model of methicillin-sensitive Staphylococcus aureus].

23 rabbits with Staphylococcus aureus methicillin-sensitive, SAMS, experimentally induced endocarditis (EIE) were studied to compare the efficacy of cloxacillin vs the association cloxacillin-gentamicin. Twelve animals made the control group and 11 the treated ones, 5 with cloxacillin-gentamicin and 6 with cloxacillin. The animals were treated 3 days, then, mortality, blood cultures at 48 and 72 hours and the title of the unit-forming colonies per gram of vegetation (UFC/g) were evaluated. The control group had a mortality of 100% in the first 72 hours, its blood cultures were positive at 48 and 72 hours and the UFC/g was 10,48 o 0.20. There was statistical significance between the control group and both treatment, in mortality, blood culture's positivity and the UFC/g of vegetation. This results confirm the similar efficacy of cloxacillin either alone or in combination in the treatment of SAMSIE and the effectiveness of the experimental model to evaluate antimicrobial treatments.

Animals↗

PubMed1985

Electron microscopic study of leucocytic infiltration of the mammary teat duct during infection with Staphylococcus aureus.

Leucocytic response to Staphylococcus aureus infection was observed in the bovine mammary teat duct using transmission electron microscopy. Leucocytes migrating across the stratified squamous epithelium were observed in close association with areas colonised by cocci. Leucocytes gained access across the epithelium to the teat duct lumen by: passage as luminal cells desquamated; migration through degenerate cell cytoplasm; and penetration of cell junctions. The results provide evidence of marked leucocytic infiltration into ductal tissue which may participate in the cellular response to mastitis.

Animals↗

PubMed1982

Phase I trial of Staphylococcus aureus Cowan I immunoperfusion.

Staphylococcus aureus Cowan I has shown antitumor activity in in vitro and in animal tumor models. It is hypothesized that this antineoplastic effect results from the interaction of protein A on the cell surface of Cowan I strain S. aureus and immunosuppressive circulating immune complexes. Therefore, we treated five patients with ex vivo plasma immuno-perfusion over killed and fixed S. aureus Cowan I. Toxic effects were marked in all patients and appeared to be related to the plasma volume infused and rate of infusion. Toxic reactions occurred in the cardiovascular, respiratory, and hematopoietic systems. No responses even minimal or transient, were observed in this phase I trial. This toxicity may be reduced if the rate of plasma infusion decreases.

Adult↗

PubMed2006

Staphylococcus aureus and endoscopic sinus surgery.

PURPOSE OF REVIEW: The current recommendation for the choice of empiric antibiotic therapy of chronic rhinosinusitis is based on the bacteriology of acute rhinosinusitis. Staphylococcus aureus has been found consistently in cultures from patients with chronic rhinosinusitis. New studies have examined the role of Staphylococcus aureus in the pathogenesis and clinical course of chronic rhinosinusitis, both before and after surgical therapy. The consequence of antibiotic resistance, on the course of chronic rhinosinusitis and its treatment, has also been examined. RECENT FINDINGS: Several recent studies have confirmed past literature demonstrating a high incidence of sinus cultures positive for Staphylococcus aureus growth in patients with chronic rhinosinusitis. Moreover, one study reported that Staphylococcus aureus is common in patients with persistent chronic rhinosinusitis after endoscopic sinus surgery. These studies, however, have not shown that this bacterium is a significant factor in the development of chronic rhinosinusitis or a predictor of the severity of symptoms. Other studies did not support the notion of increased antibiotic resistance in chronic rhinosinusitis, although there is some evidence that antibiotic resistance may lead to refractory cases of the disease. The standard treatment, of multiple courses of empiric antibiotics followed by surgery, was not shown to increase the prevalence of methicillin-resistant Staphylococcus aureus. SUMMARY: A review of recent literature shows a high incidence of positive cultures for Staphylococcus aureus from the sinuses of patients with chronic rhinosinusitis, both before and after surgery, but has not produced convincing evidence that Staphylococcus aureus has a significant role in the pathogenesis or clinical course of the disease.

Chronic Disease↗

PubMed2006

Methicillin resistant Staphylococcus aureus: is it a problem for nasal surgery?

Methicillin resistant Staphylococcus aureus (MRSA) is becoming ever more prevalent in the UK, and the proportion of MRSA to methicillin sensitive Staphylococcus aureus (MSSA) seems to be increasing. New strains of MRSA are ever developing resistance to antibiotic treatment, increasing morbidity and mortality of infection. Staphylococcus aureus is part of the normal flora of the nose, and MRSA colonizes the nose in infection. However, nasal surgery is rarely complicated by staphylococcal infections, and MRSA infection following nasal surgery is rare. The authors present a literature review of MRSA infection, its relation to the nasal cavity, and infection following nasal surgery.

Carrier State↗

PubMed2001

Involvement of mitogen-activated protein kinase pathways in Staphylococcus aureus invasion of normal osteoblasts.

Staphylococcus aureus invades osteoblasts and can persist in the intracellular environment. The present study examined the role of osteoblast mitogen-activated protein kinase (MAPK) pathways in bacterial invasion. S. aureus infection of normal human and mouse osteoblasts resulted in an increase in the phosphorylation of the extracellular signal-regulated protein kinases (ERK 1 and 2). This stimulation of ERK 1 and 2 correlated with the time course of S. aureus invasion, and bacterial adherence induced the MAPK pathway. ERK 1 and 2 phosphorylation was time and dose dependent and required active S. aureus gene expression for maximal induction. The nonpathogenic Staphylococcus carnosus was also able to induce ERK 1 and 2 phosphorylation, albeit at lower levels than S. aureus. Phosphorylation of the stress-activated protein kinases was increased in both infected human and mouse osteoblasts; however, the p38 MAPK pathway was not activated in response to S. aureus. Finally, the transcription factor c-Jun, but not Elk-1 or ATF-2, was phosphorylated in response to S. aureus infection.

Animals↗

PubMed1994

Comparison of four genotyping assays for epidemiological study of methicillin-resistant Staphylococcus aureus.

Twenty-six methicillin-resistant Staphylococcus aureus strains were genetically differentiated by interrepeat PCR and the results compared with those of ribotyping, pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis obtained in a previous study for the same strains. The comparison showed that the PCR-mediated assays were as discriminatory as PFGE, whereas ribotyping was the least powerful genotyping method. Due to the ease of performance, PCR fingerprinting may become the method of choice for establishing clonal relationship among Staphylococcus aureus isolates.

Genetic Techniques↗

PubMed1997

Isolation and characterization of autolysin-defective mutants of Staphylococcus aureus that form cell packets.

Staphylococcus aureus produces multiple bacteriolytic enzymes (autolysins) and grows usually as a mixture of single cells, pairs, short chains, and irregular clusters. Autolysin-defective mutants that form cubic cell packets (Pa4A and PaH13) or grape-like clusters (Cu9S and CuD10) were isolated from S. aureus FDA 209P after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. The Pa4A mutant grown in nutrient broth formed cell packets consisting of 8-64 cells that appeared regularly arranged in three dimensions. Thin-section electron micrographs revealed that the packet cells were encased in an orderly manner within a thick peripheral wall and that their septa failed to split. Zymographic analysis of enzyme extracts from mutant Pa4A showed that it lacked the 33-kDa autolytic enzyme band present in the parent strain. Another mutant, Cu9S, formed grape-like clusters and showed a single autolytic enzyme band (33-kDa). The possibility that the 33-kDa autolytic enzyme is involved in splitting of the septum prior to cell separation inS. aureus is discussed.

Methylnitronitrosoguanidine↗

PubMed2001

[Methicillin-resistant Staphylococcus aureus--the pathogen].

Methicillin resistant Staphylococcus aureus (MRSA) are resistant to all beta-lactams, and in more than 90% to ciprofloxacin and in 50-60% also to other groups of antibiotics, glycopeptides, quinupristin and linezolid excluded. A special problem is posed by glycopeptide intermediate susceptible S. aureus (GISA) which are until now rate in Germany, By molecular typing epidemic MRSSA can be identified which have a pronounced capacity for intra- and interhospital spread. MRSA are not more but also not less virulent than sensitive S. aureus.

Cross Infection↗

PubMed1979

Augmentation and inhibition of delayed hypersensitivity by Staphylococcus aureus protein A.

The injection of Staphylococcus-aureus protein A into mice, previously exposed to an antigen (sheep red blood cells), is capable of augmenting or inhibiting a primary delayed hypersensitivity (DH) response. SPA enhances DH response to SRBC when given with a greater than optimal sensitizing dose of the antigen. At antigen doses optimal for eliciting DH to SRBC, SPA inhibited DH. A proposed mechanism for the action of Staphylococcus-aureus protein A is based upon the ability of the protein to function as a Fc cellular receptor, thus neutralizing the effect of antigen-antibody immune complexes on DH. The binding of protein A to the Fc portion of antigen-antibody immune complexes effectively prevents subsequent binding of these complexes to Fc cellular receptors, thus eliminating their participation as co-factors in inter-cellular immunological communication. The ability of protein A to both augment and inhibit DH suggests a role for relative concentrations of serum factors and/or cellular receptors in the regulation of a primary DH response.

Animals↗

PubMed2005

Enterotoxigenic Staphylococcus aureus in bulk milk in Norway.

AIMS: To investigate the presence of enterotoxigenic Staphylococcus aureus in bulk milk and in a selection of raw milk products. METHODS AND RESULTS: Samples of bovine (n = 220) and caprine (n = 213) bulk milk, and raw milk products (n = 82) were analysed for S. aureus. Isolates were tested for staphylococcal enterotoxin (SE) production (SEA-SED) by reversed passive latex agglutination and for SE genes (sea-see, seg-sej) by multiplex PCR. Staphylococcus aureus was detected in 165 (75%) bovine and 205 (96.2%) caprine bulk milk samples and in 31 (37.8%) raw milk product samples. Enterotoxin production was observed in 22.1% and 57.3% of S. aureus isolates from bovine and caprine bulk milk, respectively, while SE genes were detected in 52.5% of the bovine and 55.8% of the caprine bulk milk isolates. SEC and sec were most commonly detected. A greater diversity of SE genes were observed in bovine vs caprine isolates. CONCLUSIONS: Staphylococcus aureus seems highly prevalent in Norwegian bulk milk and isolates frequently produce SEs and contain SE genes. Enterotoxigenic S. aureus were also found in raw milk products. SIGNIFICANCE AND IMPACT OF THE STUDY: Staphylococcus aureus in Norwegian bovine and caprine bulk milk may constitute a risk with respect to staphylococcal food poisoning from raw milk products.

Animals↗

PubMed1991

[The use of semi-starvation nutrient media for phage typing of Staphylococcus aureus].

A total of 161 Staphylococcus aureus strains grown in Hottinger's broth and semi-starvation medium (1% peptone water with 1% glycerol) were phage-typed. 107 (66.4 +/- 3.1%) of the 161 cultures grown in the semi-starvation medium could be typed and only 77 (48.1 +/- 3.63%) of the 161 grown in Hottinger's broth, which fact speaks in favor of semi-starvation nutrient media employment for phage-typing of S. aureus.

Bacteriophage Typing↗

PubMed1996

A high molecular weight protein from Staphylococcus intermedius cross-reacts with Staphylococcus aureus enterotoxin antibodies.

Enterotoxin production by Staphylococcus species other than Staphylococcus aureus has been reported. Staphylococcus strains (104 in toto) representing twelve species and subspecies were examined for enterotoxins using a commercial staphylococcal enterotoxin ELISA immunoassay (TECRA, International Bioproducts). Staphylococcus intermedius (24 strains) and S. aureus (7 strains) were positive with this test. Western blots of S. aureus exoproteins demonstrated proteins of approximately 30 kD, consistent with known staphylococcal enterotoxins. The major antigen in all S. intermedius strains, a 75 kD protein, was not analogous to previously described staphylococcal enterotoxins. This protein was unique to S. intermedius. Gel filtration data indicate that the protein is a subunit of a larger protein in vivo. The 75 kD protein cross-reacts with several enterotoxin antibodies. It is unclear whether the protein is a toxin, but its homology with S. aureus enterotoxins may indicate a shared toxic region, or this protein may create false positive results in screening for enterotoxin.

Antibodies, Bacterial↗

PubMed1984

Subinhibitory concentrations of imipenem induce increased resistance to methicillin and imipenem in vitro in methicillin-resistant Staphylococcus aureus.

Methicillin-resistant (MR) Staphylococcus aureus that was susceptible to less than 0.75 micrograms of imipenem per ml demonstrated inducible resistance. MR S. aureus preincubated with 0.05 microgram of imipenem per ml grew in medium with an imipenem concentration of 32 micrograms/ml, and methicillin MICs increased 20-fold. Non-MR S. aureus exhibited no induction. Preincubation with methicillin produced no effect. Induction appeared to be a unique interaction of imipenem with MR S. aureus.

Enzyme Induction↗

PubMed1991

Comparative evaluation of five agglutination techniques and a new miniaturized system for rapid identification of methicillin-resistant strains of Staphylococcus aureus.

The speciation of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant diagnostic problem when rapid identification methods such as slide agglutination tests, are used, because of the high proportion of false-negative reactions. 150 perfectly identified MRSA strains were tested on 5 commonly used agglutination reagents ("Bacto staph latex test", "Monostaph", "Pastorex staph", "Staphaurex", and "Staphyslide test") in comparison with a new micromethod ("RAPIDEC staph") which detects a type of staphylocoagulase within 2 hours by a fluorescence test. The "RAPIDEC staph" reagent enabled identification of all the MRSA while the agglutination tests gave poorer results: "Monostaph" correctly identified 64.6% of strains, "Staphyslide", 59.3%, "Bacto staph latex test", 44.6%, "Pastorex staph", 38.6% and "Staphaurex", 28.6%. These results show that agglutination slide tests are not reliable enough for the identification of MRSA which are more and more encountered in hospital wards. The authors recommend not to use slide agglutination methods. They suggest the tube test for coagulase which is the reference technique, although it is time-consuming and not well standardized. The results of this evaluation encourage the use of the "RAPIDEC staph" reagent since it is an easy-to-use, reliable technique for the rapid identification of Staphylococcus aureus.

Agglutination Tests↗

PubMed1988

Evaluation of the Rapid Mastitis Test for identification of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands.

A latex agglutination test system (Rapid Mastitis Test [RMT]; Immucell, Portland, Maine) containing reagents for the identification of Staphylococcus aureus and Streptococcus agalactiae from bovine intramammary infections was evaluated with 527 staphylococcal and 267 streptococcal isolates. The RMT Staphylococcus aureus reagent detected 94.2% of 242 Staphylococcus aureus isolates, 80% of 25 Staphylococcus intermedius isolates, and 42.8% of 21 tube coagulase-positive Staphylococcus hyicus isolates. All Streptococcus agalactiae isolates were correctly identified by the RMT Streptococcus agalactiae reagent. Cross-reactions were observed with one Streptococcus dysgalactiae and three Streptococcus uberis strains. The RMT was found to be an acceptable method for the detection of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands. The occurrence of coagulase-positive staphylococci other than Staphylococcus aureus requires biochemical testing for species level identification.

Animals↗

PubMed1991

Southern hybridization analysis of the mecA deletion from methicillin-resistant Staphylococcus aureus.

Genomic organization of methicillin-resistant Staphylococcus aureus strains and their methicillin-susceptible subclones were analyzed by pulsed-field gel electrophoresis and Southern hybridization with DNA fragments of methicillin-resistance gene mecA and an insertion element IS431 as probes. The entire mecA gene was deleted in all the seven methicillin-susceptible subclones studied, and the size of the deletion varied from 20 to 100 kilobases depending on each subclone. In six of the seven subclones, however, the downstream deletion end points were confined within a 2.0 kilobase HindIII-HindIII fragment containing a part of IS431 which was located 2.6 kilobase downstream of mecA gene. The results indicated that the intramolecular transposition of IS431 is responsible for the mecA deletion in methicillin-resistant Staphylococcus aureus.

Blotting, Southern↗