SEARCH · PubMed Health

Results for “Staphylococcus aureus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources

PubMed1974

Plasmid-mediated production of staphylococcin in bacteriophage type 71 Staphylococcus aureus.

Staphylococcin production by Staphylococcus aureus strain C55 was eliminated when producing strains were exposed to various curing treatments. Acridine orange, ethidium bromide, and sodium dodecyl sulfate each effected less than 15% cure rates in treated cells. Rifampin eliminated the staphylococcin in 83% of treated isolates, and growth at 42 C resulted in a 97% cure rate. Curing of staphylococcin production and elimination of penicillinase plasmid were independent of one another. Several characteristics of the cured strains were examined and compared with the bacteriocin-producing strains. Whereas bacteriocin-producing cells were resistant to the bactericidal action of the staphylococcin and failed to adsorb it, cured cells adsorbed the staphylococcin and were susceptible to its lethal effect.

Bacteriocins↗

PubMed2006

Colony spreading in Staphylococcus aureus.

Wild-type Staphylococcus aureus rapidly expands on the surface of soft agar plates. The rates of expansion and the shapes of the resultant giant colonies were distinct for different strains of laboratory stocks and clinical isolates. The colony spreading abilities did not correlate with the biofilm-forming abilities in these strains. Insertional disruption of the dltABCD operon, which functions at the step of D-alanine addition to teichoic acids, and of the tagO gene, which is responsible for the synthesis of wall teichoic acids, decreased the colony spreading ability. The results indicate that wall teichoic acids and D-alanylation of teichoic acids are required for colony spreading.

Agar↗

PubMed2004

The von Willebrand factor-binding protein (vWbp) of Staphylococcus aureus is a coagulase.

Staphylococcus aureus encodes a secreted von Willebrand factor-binding protein (vWbp) of 482 amino acids. The N-terminal part of this protein is homologous to staphylocoagulase and therefore we investigated whether vWbp has coagulating activity. Recombinant vWbp was shown to coagulate human and porcine plasma efficiently, but was less active against plasma from other species. The coagulation efficiency was concentration dependent, and could be inhibited by specific antibodies against vWbp. Furthermore, the species-specific coagulation by vWbp depended on the interaction with prothrombin. This interaction also resulted in specific cleavage of vWbp, releasing the C-terminal part from the coagulating domain.

Animals↗

PubMed2005

DNA sequence-based tandem repeat analysis of the clfB gene is less discriminatory than spa typing for methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) are a major challenge for hospital hygiene. Typing by DNA sequence analysis of the repeat region of the protein A gene (spa) significantly improved typing of MRSA in the hospital setting. However, microevolution of spa repeats in epidemic clones appears to occur at a fairly slow clock rate. Therefore, DNA sequence-based methods providing additional resolution are desirable in some situations. We evaluated the use of the clfB repeat region proposed recently by others as a possible complementation to spa typing. Using epidemic MRSA isolates from two German university hospitals, we show that the clfB repeat region does not offer any additional discriminatory power.

Adhesins, Bacterial↗

PubMed1994

Clonal study of enterotoxin-B producing strains of Staphylococcus aureus.

Sixty-nine Staphylococcus aureus strains, 39 of which produced staphylococcal enterotoxin B (SEB+) and 14 of which were associated with toxic shock (TS+), were studied using the following markers: serotyping, phage typing, antibiotyping, ribotyping, zymotyping and pulsed-field electrophoresis typing. Analysis of the results showed that the enterotoxin B producing strains were derived from at least three clones: the first two consisted of methicillin-susceptible strains, while the third included the methicillin-resistant (MRSA) strains. TS+ strains of nongenital origin appeared to be distributed between the three clones, with no specific characters.

Bacteriophage Typing↗

PubMed1993

Microbicidal effects of ozone solution on methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus has become an important problem in chemotherapy in the past decade because of its resistance to commonly used disinfectants. The usefulness of ozone solutions to disinfect against strains of this bacterium has been evaluated. Ozone strongly oxidizes the cell walls and cytoplasmic membranes of bacteria. The microbicidal effect of ozone solutions took place within the first five seconds of treatment. An ozone concentration 1.5 times that needed to kill the one methicillin-sensitive strain tested was sufficient to kill the resistant clinical isolates. Such an ozone solution could be used to disinfect medical instruments and similar equipment. Ozone solutions should be useful in reducing the number of bacterial infections caused by inadequate disinfection against new resistant strains.

Disinfectants↗

PubMed1998

Acquisition of methicillin resistance and progression of multiantibiotic resistance in methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) produces specific penicillin-binding protein, PBP2', which shows remarkably low affinities to most beta-lactam antibiotics except those such as penicillin G and ampicillin. The region surrounding mecA has been called additional DNA or mec and is thought to be of extraspecies origin. From the study of mec, we found that mec is a novel mobile genetic element and designated as staphylococcal cassette chromosome mec (SCCmec). There are three types of SCCmec. In the past decades, MRSA has become resistant to many antibiotics, such as carbapenems, new quinolones, and minocycline etc. It seems to be a characteristic of MRSA to acquire multi-resistance by accumulating multiple resistance genes around the mecA gene inside SCCmec.

Drug Resistance, Microbial↗

PubMed2006

High-intensity pulsed electric field variables affecting Staphylococcus aureus inoculated in milk.

Staphylococcus aureus is an important milk-related pathogen that is inactivated by high-intensity pulsed electric fields (HIPEF). In this study, inactivation of Staph. aureus suspended in milk by HIPEF was studied using a response surface methodology, in which electric field intensity, pulse number, pulse width, pulse polarity, and the fat content of milk were the controlled variables. It was found that the fat content of milk did not significantly affect the microbial inactivation of Staph. aureus. A maximum value of 4.5 log reductions was obtained by applying 150 bipolar pulses of 8 mus each at 35 kV/cm. Bipolar pulses were more effective than those applied in the monopolar mode. An increase in electric field intensity, pulse number, or pulse width resulted in a drop in the survival fraction of Staph. aureus. Pulse widths close to 6.7 micros lead to greater microbial death with a minimum number of applied pulses. At a constant treatment time, a greater number of shorter pulses achieved better inactivation than those treatments performed at a lower number of longer pulses. The combined action of pulse number and electric field intensity followed a similar pattern, indicating that the same fraction of microbial death can be reached with different combinations of the variables. The behavior and relationship among the electrical variables suggest that the energy input of HIPEF processing might be optimized without decreasing the microbial death.

Animals↗

PubMed2005

Effects of tannins and related polyphenols on methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) often acquires multi-drug resistance and is involved in many cases of disease in hospitals. We investigated natural substances directly effective against MRSA or that influence antibiotic resistance. Aloe-emodin, an anthraquinone, and several licorice flavonoids showed potent antibacterial effects against MRSA. Like some hydrolysable tannins (corilagin and tellimagrandin I) and a tea polyphenol [(-)-epicatechin gallate], the licorice flavonoid licoricidin also restored the effects of oxacillin, a beta-lactam antibiotic against MRSA. Further study revealed that theasinensin A, a polyphenol formed from (-)-epigallocatechin gallate, proanthocyanidins obtained from fruits of Zizyphus jujuba var. inermis, and polymeric proanthocyanidins from fruit peels of Zanthoxylum piperitum also suppressed the antibiotic resistance of MRSA.

Flavonoids↗

PubMed1984

Low-affinity penicillin-binding protein associated with beta-lactam resistance in Staphylococcus aureus.

Methicillin resistance in Staphylococcus aureus has been associated with alterations in the penicillin-binding proteins (PBPs). An intriguing property of all methicillin-resistant staphylococci is the dependence of resistance on the pH value of the growth medium. Growth of such bacteria at pH 5.2 completely suppressed the expression of methicillin resistance. We have examined the PBP patterns of methicillin-resistant staphylococci grown at pH 7.0. We detected a high-molecular-weight PBP (PBP-2a; approximate size, 78,000 daltons) that was only present in the resistant bacteria but not in the isogenic sensitive strain. In cultures grown at pH 5.2, the extra PBP was not detectable.

Bacterial Proteins↗

PubMed2001

Regulation of virulence determinants in Staphylococcus aureus.

The pathogenicity of Staphylococcus aureus depends on the combined action of more than 40 different extracellular toxins, enzymes and cell surface proteins. A global regulator agr controls the production of many of these virulence factors by a regulating RNA molecule, RNAIII. Most of the virulence genes regulated by RNAIII are also regulated by SarA and a family of homologous proteins. The Sar proteins appear to repress transcription of individual virulence genes or sets of genes. As some Sar proteins also repress one or more sar homologous genes an increased production of a single Sar protein can result in decreased expression of some virulence genes, and an increased expression of others. Results are presented suggesting that RNAIII might function as an antirepressor, binding one or more of the Sar proteins.

Base Sequence↗

PubMed1979

Properties of an unusual genetic element in Staphylococcus aureus.

A strain of Staphylococcus aureus (M7) contains a transmissible element determining production of penicillinase, and resistance to cadmium ions, neomycin, streptomycin and kanamycin (CPNS). This element was transferred either in toto or in fragments at low frequency from strain M7. The fragment (NS) possesses features typical of chromosomal genes and the fragment (CP), like (CPNS) itself, exhibits plasmid features. The element (CPNS) is transferred in mixed culture at high frequency, up to 10(-3), between other strains of staphylococci. Lysogenisation of the recipient increases the frequency of transfer. The frequency of transduction of (CPNS), (CP) and (NS) from cell-free lysates corresponds well with the transfer frequency of each of these elements in mixed culture. A possible mechanism for the evolution of (CPNS) is discussed.

Anti-Bacterial Agents↗

PubMed1978

[Detection of penicillinase and bacteriocinogenicity plasmids in Staphylococcus aureus strain No. 580].

Staphylococcus aureus No. 580 strain contains simultaneously two plasmids: bacteriocinogenicity plasmid and penicillinase plasmid. Both plasmids are lost spontaneously with a high frequency, and also under the effect of acridine orange at temperatures of 37 degrees C and 44 degrees C, and in cultivation at a temperature of 44 degrees C for 5 days. Loss of one of the plasmids failed to lead to stabilization of another plasmid, and it was eliminated spontaneously with the same frequency as in the population of the initial strain. Plasmid loss did not lead to the changes in biochemical and pathogenic properties and also of the phagovar and bacteriogenovar. At the same time in elimination of one or both plasmids lag-phase diminished from 220 to 120 min.

Acridine Orange↗

PubMed2004

[The efficacy of function water (electrolyzed strong acid solution) on open heart surgery; postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus].

Methicillin-resistant Staphylococcus aureus (MRSA) infection after cardiac surgery has recently increased. We compared the anti-inflammatory effect of an electrolyzed strong acid solution and a warm saline solution in patients with open heart surgery. These solutions were used for mediastinal irrigation before closing the sternum. Group A patients were irrigated by a warm saline solution, and group B patients were irrigated by an electrolyzed strong acid solution, administration of this water is safe, feasible, and easy for the prevention of MRSA infection. Postoperative infection was significantly decreased in the group B as compared in the group A. An electrolyzed strong acid solution may be effective on postoperative infection, particularly MRSA infection following open heart surgery.

Aged↗

PubMed2005

Structural insight into binding of Staphylococcus aureus to human fibronectin.

Staphylococcus aureus possesses cell-wall attached proteins that bind the human protein fibronectin (Fn). An intermodule interface between the 4F1 and 5F1 modules in the N-terminal domain of Fn is maintained on bacterial peptide binding but there is a small change in the intermodule orientation and alignment of beta-strands that are predicted to bind the peptide. The module pair is elongated, as in the unbound state. Combined with evidence that residues in both 4F1 and 5F1 are directly involved in peptide binding, this observation supports the hypothesis that, when bound to intact Fn, the bacterial protein adopts an unusual, highly extended conformation.

Adhesins, Bacterial↗

PubMed2005

The clinical significance of methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for the largest outbreak of hospital-acquired infection (HAI) that the world has ever seen. It is not replacing methicillin-susceptible S. aureus (MSSA), but seems largely to be an additional burden of HAI with double the mortality of MSSA infections, at least in the bacteraemic form. It is often highly transmissible and carriage seems to lead to clinical infection much more frequently than with MSSA carriage. Additional screening for MRSA needs to be performed, not only to establish the size of the problem and to allow initiation of decolonization measures to prevent the onset of clinical disease, but also to allow implementation of infection control precautions that will be necessary to control the epidemic. MRSA is a huge clinical burden that is causing great public and political concern. Current treatments are suboptimal. Control measures are likely to be effective and cost saving if they have a broad enough base, and should be implemented without further delay.

Cross Infection↗

PubMed1996

Bacterial doubling time modulates the effects of opsonisation and available iron upon interactions between Staphylococcus aureus and human neutrophils.

Staphylococcus aureus was grown exponentially at two doubling times (DT), one related to in vivo (DT 60 min) and one typical of laboratory conditions (DT 24 min), and under iron-poor and iron-rich conditions. Relative to the fast-grown phenotypes, both slow-grown phenotypes exhibited low surface hydrophobicity and low protein A expression, induced poorly in non-opsonised and opsonised chemiluminescence, and survived well in whole blood killing. In particular, slow-grown, iron-poor cocci demonstrated enhanced survival in whole blood killing which correlated with significant reduction in their association with polymorphonuclear leukocytes, compared to the three other phenotypes; iron sufficiency increased the ability to stimulate polymorphonuclear leukocytes irrespective of opsonisation status. Staphylococcal DT may, by influencing surface hydrophobicity, modify interactions with immune system components.

Blood Bactericidal Activity↗

PubMed2005

Relationships between toxin gene content and genetic background in nasal carried isolates of Staphylococcus aureus from Asturias, Spain.

Staphylococcus aureus recovered from nasal carriers, producers and non-producers (43 isolates each) of classical pyrogenic toxin superantigens (PTSAgs), were screened for 17 additional PTSAg-genes by PCR. Percentages of 88.4 and 65.1 were positive for some new enterotoxin-gene, and 76.7 and 55.8 for enterotoxin-gene-clusters (egc-like), respectively. The 86 isolates belonged to 17 toxin-genotypes (all eta-, etb-, etd-, see- and sep-negative), and generated 40 SmaI-genomic profiles that in a dendrogram of similarity (S0.7) clustered into nine lineages and 11 non-clustered branches. Correlations between classical PTSAgs and SmaI-lineages were established and egc-like groupings appeared dispersed in six lineages.

Bacterial Toxins↗