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PubMed1982

In vitro cartilage degradation by Escherichia coli and Staphylococcus aureus.

Effects of Escherichia coli and Staphylococcus aureus on cartilage and chondrocytes in culture are reported. Under these conditions, bacterial effects on cartilage degradation and cell viability are measured in the absence of inflammation. E coli causes a 28% loss and S aureus an 83% loss of cartilage glycosaminoglycan within 48 hours. Collagen content is unchanged. Both bacterial species induce chondrocyte death in explants and in monolayers within 48 hours. Bacterial effects on glycosaminoglycans and cell viability do not result from depletion of nutrients from the culture medium. Serum in the culture media inhibits the bacterial effects on cartilage degradation but does not prevent cell death.

Animals↗
PubMed2005

Detection of galangin-induced cytoplasmic membrane damage in Staphylococcus aureus by measuring potassium loss.

Galangin is one of the active antimicrobial principles of propolis or 'bee glue' and Helichrysum aureonitens, a perennial herb used by South African indigenes to treat infection. The effect of this compound and antibacterial agents with known mechanisms of action upon the cytoplasmic membrane integrity of Staphylococcus aureus was investigated by comparing potassium loss profiles from bacterial cell suspensions. Using an agar dilution assay, the minimum inhibitory concentrations (MICs) of the flavonol galangin, the bacteriostatic antibiotic novobiocin and the bactericidal antibiotic penicillin G against Staphylococcus aureus NCTC 6571 were determined as being 50 microg/mL, 62.5 ng/mL and 31.3 ng/mL, respectively. When 5x10(7)cfu/mL Staphylococcus aureus were suspended in 'potassium-free' media containing 50 microg/mL galangin, a 60-fold decrease in viability was observed after 12 h. Populations of 1x10(9) cfu/mL Staphylococcus aureus incubated for 12 h in 50 microg/mL galangin lost 21% more potassium than untreated control populations. Novobiocin had no effect on potassium loss, but populations incubated in 31.3 ng/mL penicillin G exhibited a 6% increase in potassium loss. This data clearly demonstrates that galangin causes a significant increase in potassium loss from Staphylococcus aureus cells, which may be attributed to either direct damage to the cytoplasmic membrane or indirect damage effected through autolysis/weakening of the cell wall and consequent osmotic lysis.

Anti-Bacterial Agents↗
PubMed1984

Plasmids of phage-Group-II Staphylococcus aureus.

Most phage-Group-II Staphylococcus aureus have been shown to carry at least one plasmid. The proportion of strains that are resistant to tetracycline appears to have increased during the last 17 years. Restriction maps of several of the small plasmids isolated from Group-II strains are presented and compared with those known for staphylococcal plasmids. These small plasmids are similar to previously characterised plasmids from staphylococci of other phage groups.

Bacteriophage Typing↗
PubMed2005

Characterization of a multicopper oxidase gene from Staphylococcus aureus.

A multicopper oxidase gene from Staphylococcus aureus was cloned and overexpressed. Purified recombinant multicopper oxidase oxidized the substrate 3,3'-dimethoxybenzidine in the presence of copper. Disruption of mco showed copper sensitivity and H(2)O(2) resistance, suggesting roles for mco in copper homeostasis and oxidative stress response. Northern blot analysis showed copper-induced mco transcription.

Cloning, Molecular↗
PubMed1988

Positive reaction in mouse ligated intestinal loop assay with nonenterotoxigenic and nonhemolytic strains of Staphylococcus aureus.

Nonenterotoxigenic and nonhemolytic strains of Staphylococcus aureus exhibited a positive reaction in the mouse intestinal loop assay except for a strain negative for the egg yolk reaction. Edema and swelling in all positive loops, increased bacterial cell numbers within intestinal loops, and extremely close adhesion to or inclusion of numerous bacterial cells in HeLa cells after inoculation of the strains were observed. These results suggest a possible invasive ability of the strains.

Animals↗
PubMed1979

Catalase activity during the recovery of heat-stressed Staphylococcus aureus MF-31.

Sublethal heating of Staphylococcus aureus produced little loss of catalase activity, but incubation of the injured cells in tryptic soy broth, with or without 10% NaCl added, produced an 85% decrease in catalase activity. Cells recovered in tryptic soy broth demonstrated increases in catalase levels after approximately 5 h, whereas in tryptic soy broth with 10% NaCl the levels remained low for at least 12 h. Thus, the loss of catalase activity during the recovery period was greater than during the heat treatment.

Catalase↗
PubMed1975

Staphylococcal polysaccharide products inhibitory to Staphylococcus aureus bacteriophage.

Four products derived from Staphylococcus aureus cultures were partially purified and tested for inhibitory activity against staphylococcal phage. Phage inhibition, a specific stable phenomenon, was concentration dependent. All inhibitory products contained carbohydrate and amino acids, the most active (phage 73 lysate product) having a high carbohydrate content. Galactose, glucosamine, five or six amino acids, and possibly 3-O-methylglucose and a uronic acid were found as components in all active preparations. However, the exact nature of the active material remains undetermined.

Cell Wall↗
PubMed2000

Cell wall-associated protein A as a tool for immunolocalization of Staphylococcus aureus in infected human airway epithelium.

Staphylococcus aureus is a common human pathogen involved in non-bronchial diseases and in genetic and acquired bronchial diseases. In this study, we applied an immunolabeling approach for in vivo and in vitro detection of S. aureus, based on the affinity of staphylococcal protein A (SpA) for the Fc region of immunoglobulins, especially IgG. Most strains of S. aureus, including clinical strains, can be detected with this labeling technique. The approach can be used for detection and localization with transmission electron microscopy or light-fluorescence microscopy of S. aureus in infected tissues such as human bronchial tissue from cystic fibrosis (CF) patients. The methodology can also be applied to cell culture models with the aim of characterizing bacterial adherence to epithelial cells in backscattered electron imaging with scanning electron microscopy. Application to the study of S. aureus adherence to airway epithelium showed that the bacteria did not adhere in vivo to intact airway epithelium. In contrast, bacteria adhered to the basolateral plasma membrane of columnar cells, to basal cells, to the basement membrane and were identified beneath the lamina propria when the epithelium was injured and remodeled, or in vitro when the epithelial cells were dedifferentiated.

Adult↗
PubMed1993

Cloning, expression, and mutagenesis of phosphatidylinositol-specific phospholipase C from Staphylococcus aureus: a potential staphylococcal virulence factor.

Staphylococcus aureus secretes a phosphatidylinositol (PI)-specific phospholipase C (PI-PLC) which is able to hydrolyze the membrane lipid PI and membrane protein anchors containing glycosyl-PI. The gene for PI-PLC (plc) was cloned from S. aureus into Escherichia coli. Oligonucleotide probes based on partial protein sequence and polyclonal antibodies raised against the purified protein were used to identify positive clones. E. coli transformed with a plasmid containing the plc gene expressed PI-PLC enzyme activity which was abolished by mutagenesis with a tetracycline resistance gene. The plc gene was present in all 15 S. aureus strains examined but not in any of 6 coagulase-negative staphylococcal species. The plc gene contained 984 bp and coded for a mature protein with a calculated molecular mass of 34,107 Da. Amino acid sequence comparisons indicated that the staphylococcal plc gene was similar (51 to 56%) to the PI-PLCs from Bacillus cereus, Bacillus thuringiensis, and Listeria monocytogenes. The recombinant PI-PLC expressed in E. coli was purified and exhibited biochemical properties identical to those of the native PI-PLC from S. aureus. PI-PLC production was decreased in agr mutant strains of S. aureus. However, PI-PLC production by both agr+ and agr mutant strains exhibited a similar dependence on the type of medium used. These data suggested that PI-PLC production was regulated by both agr-dependent and agr-independent mechanisms.

Amino Acid Sequence↗
PubMed2002

Novel locus required for expression of high-level macrolide-lincosamide-streptogramin B resistance in Staphylococcus aureus.

The yycF1(Ts) mutation in Staphylococcus aureus conferred hypersensitivity to macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics on strains either containing or lacking ermB. The overexpression of the S. aureus Ssa protein restored the yycF1 mutant to wild-type levels of susceptibility. Inactivation of ssa in an unmutagenized strain dramatically reduced ermB-based resistance. Conditional loss of function or expression of ssa in the yycF1 mutant is proposed to result in the observed hypersensitivity to MLS(B) antibiotics.

Amino Acid Sequence↗
PubMed1979

Composition and evaluation of the efficacy of Staphylococcus aureus vaccine.

An alum-precipitated Staphylococcus aureus vaccine, composed of a formalin-inactivated whole culture of a strain which produces Smith surface antigen and combined with the whole culture of a highly toxigenic strain, was found to afford a good immunity to staphylococcal skin infection in rabbits. Three injections of the vaccine provided immunity which lasted for at least 6 months against a primarily pyogenic strain of S. aureus and for at least 3 months against a toxigenic strain. From experiments using vaccines prepared from cells or toxoid only, it was deduced that, although there is a measure of strain specific immunity, a good heterologous immunity can be established with a combined product provided that it contains adequate quantities of toxoid. The use of such a vaccine as a potential aid in the control of bovine staphylococcal mastitis is discussed.

Adjuvants, Immunologic↗
PubMed2005

Accumulation of mutations in both gyrB and parE genes is associated with high-level resistance to novobiocin in Staphylococcus aureus.

Coumarin-resistant mutants of Staphylococcus aureus were isolated by three-step selection with novobiocin at different concentrations. Sequencing analysis of the gyrB and parE genes of the first-, second-, and third-step mutants revealed that successive point mutations first occurred specifically in the gyrB gene, followed by a point mutation in the parE gene and then an additional point mutation in the gyrB gene. These findings demonstrate that DNA gyrase is the primary target and that topoisomerase IV is the secondary target for novobiocin and that the accumulation of point mutations in both the gyrB and the parE genes is associated with high-level resistance to novobiocin in S. aureus. Moreover, our results show that the amino acid substitutions (Asp-89 to Gly and Ser-128 to Leu) found in GyrB are associated with resistance to novobiocin but not to coumermycin A1, suggesting that the interactions of novobiocin and coumermycin A1 with GyrB differ at the molecular level.

Amino Acid Sequence↗
PubMed2006

Combining site-specific mutagenesis and seeding as a strategy to crystallize 'difficult' proteins: the case of Staphylococcus aureus thioredoxin.

The P31T mutant of Staphylococcus aureus thioredoxin crystallizes spontaneously in space group P2(1)2(1)2(1), with unit-cell parameters a = 41.7, b = 49.5, c = 55.6 A. The crystals diffract to 2.2 A resolution. Isomorphous crystals of wild-type thioredoxin as well as of other point mutants only grow when seeded with the P31T mutant. These results suggest seeding as a valuable tool complementing surface engineering for proteins that are hard to crystallize.

Crystallization↗
PubMed1999

Suppressive effect of ultraviolet (UVB and PUVA) radiation on superantigen production by Staphylococcus aureus.

It is well known that Staphylococcus aureus (S. aureus) proliferates on the moist skin lesion of atopic dermatitis. Reduction of bacteria colonization from skin lesions by antibiotics has been reported to be effective for the treatment of atopic dermatitis. S. aureus produces superantigens which can activate T cells and possibly enhance the inflammatory reaction. Photo(chemo)therapy has been successfully used for the treatment of severe cases of atopic dermatitis. We have previously reported that photo(chemo)therapy had bacteriostatic effect on S. aureus. Now we examined the effect of UVB and psoralen plus UVA (PUVA) on superantigen production from S. aureus. We isolated S. aureus from six atopic dermatitis patients. S. aureus was irradiated in vitro with UVB (0, 5, 10 mJ/cm2) or PUVA (0.001% psoralen plus 0, 5, 10 mJ/cm2 UVA) and incubated 4 h with 100 strokes per min. After incubation, the amounts of superantigens in the supernatant were measured using ELISA kit. The production of superantigens decreased in an ultraviolet dose-dependent manner. The suppressive effects of UV radiation on superantigen production may be involved in the therapeutic efficacy of photo(chemo)therapy for atopic dermatitis.

Dermatitis, Atopic↗
PubMed1999

Effect of fluoroquinolone concentration on selection of resistant mutants of Mycobacterium bovis BCG and Staphylococcus aureus.

When Mycobacterium bovis BCG and Staphylococcus aureus were plated on agar containing increasing concentrations of fluoroquinolone, colony numbers exhibited a sharp drop, followed by a plateau and a second sharp drop. The plateau region correlated with the presence of first-step resistant mutants. Mutants were not recovered at concentrations above those required for the second sharp drop, thereby defining a mutant prevention concentration (MPC). A C-8-methoxy group lowered the MPC for an N-1-cyclopropyl fluoroquinolone.

Anti-Infective Agents↗
PubMed1990

Role of pre-incubation in non-selective medium in recovery of Staphylococcus aureus from swimming pools and beaches.

Staphylococcus aureus was isolated from eleven open swimming pools and eleven swimming beaches in certain areas of Saudi Arabia. Pre-incubation of the water samples in a non-selective medium prior to their growth in the selective medium increased the rate of recovery over that of direct plating on the selective medium. The average increase was from 20.68% to 46.1% for pools and from 32.7% to 37.3% for beaches. Pre-incubation, therefore, is very important for the pool water which appears to contain more stressed bacteria.

Bacteriological Techniques↗
PubMed2006

Staphylococcus aureus endocarditis complicated by bilateral pneumothorax.

Staphylococcus aureus is the most common cause of endocarditis in intravenous drug users. The organism gains access by intravenous injection or from the direct invasion of skin at injection sites. Known for its aggressiveness, the right sided endocarditis that ensues can lead to complications such as pulmonary abscesses and even death. We report the unusual case of an intravenous drug abuser, who following the occurrence of extensive pulmonary abscesses, developed bilateral pneumothoraces within a few days.

Adult↗