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PubMed1973

Plasmid-specific transformation in Staphylococcus aureus.

Transformation of Staphylococcus aureus cells with circular duplex deoxyribonucleic acid prepared from plasmid-carrying strains by alkali denaturation and selective renaturation or by dye-buoyant density centrifugation is reported. In all of the transformants tested, the transformed markers became established as autonomous plasmids that were biologically and physically indistinguishable from those carried by the donor strains. Transformation with bulk deoxyribonucleic acid from a strain carrying the penicillinase plasmid, PI(258), gave rise to transformants in which the erythromycin locus, the only plasmid marker transformed, was shown to be integrated into the host chromosome.

Cadmium↗
PubMed1973

Characterization of a bacteriocin from Staphylococcus aureus strain 462.

Staphylococcus aureus 462 is one of three bacteriocin-producing strains selected for study from 200 isolates of staphylococci of animal origin. These bacteriocins are specific in their activity, inhibiting the growth of certain strains of S. aureus and other gram-positive species, but not gram-negative organisms. Staphylococcin 462 was not found in significant concentrations in the supernatant fluid of broth cultures, nor was it released into the suspending liquid when the cells were mechanically disrupted. However, extraction of the cells with 7 M urea resulted in the liberation of much of the activity. The material was purified by gel permeation chromatography by using Sephadex G-200 and by preparative electrophoresis on polyacrylamide gels in the presence of sodium dodecyl sulfate. Chemical analysis showed that the material consisted of roughly 90% protein and 3% lipid. The molecular weight of sodium dodecyl sulfate-dissociated staphylococcin 462 was calculated to be about 9,000.

Bacteriocins↗
PubMed1967

Elution of loosely bound acid phosphatase from Staphylococcus aureus.

Strains of Staphylococcus aureus from the International-Blair and the Seto-Wilson series of phage propagating strains were examined for acid phosphatase activity. This enzyme was found to occur in varying amounts in three different fractions: free (6 to 60%), loosely bound (25 to 82%), and firmly bound (0 to 46%). Propagating strain 3A, because of its high activity, was chosen for further study. The rate of enzyme production paralleled cell growth in Trypticase Soy Broth, but followed a biphasic pattern in a semisynthetic casein acid-hydrolysate medium with glyceryl phosphate. Maximal elution of acid phosphatase in the loosely bound fraction, presumably from the surface of cells, occurred in the alkaline pH range. From log-phase cells, elution was maximally effected with buffered 1.0 M KCl (pH 7.5), but stationary-phase cells required twice the concentration of KCl.

Acid Phosphatase↗
PubMed1974

Mercury and cadmium resistances mediated by the penicillinase plasmid in Staphylococcus aureus.

Resistance of Staphylococcus aureus mediated by the penicillinase (Pc-ase) plasmid to divalent metal ions of Hg and Cd was found to be controlled by different mechanisms. The Hg resistance of the Pc-ase plasmid-carrying organisms is based upon a process of changing the ion incorporated in the cell into a somewhat innocuous form. This process is independent of temperature and seems to be controlled by an inducible enzyme. The killing effect of Hg salts was not influenced by the coexistence of other di- or monovalent ions such as MgCl(2), CaCl(2), MnCl(2), and NaCl. No vaporization of Hg, which explains the resistance mechanism such as that proposed by Komura et al. for R factor-mediated Hg resistance in enterobacilli, was found in the case of Hg resistance in staphylococci. On the other hand, the resistance to Cd ion is mediated by some protective mechanism to retain the ion outside the cell. Pc-sensitive organisms not carrying the Pc-ase plasmid incorporate Cd ions into the cells, whereas the Pc-ase plasmid-carrying organisms do not. The incorporation of this ion is temperature dependent and does not take place at 4 C. When incubated with this ion at 4 C, Pc-sensitive organisms as well as Pc-resistant organisms are also able to show a resistance. The addition of CaCl(2) could eliminate the killing effect of CdCl(2) with a dose-effective response.

Cadmium↗
PubMed1999

Echocardiography for the Diagnosis of Staphylococcus aureus Infective Endocarditis.

Staphylococcus aureus bacteremia (SAB) is a serious and growing problem. A longstanding controversy in infectious diseases has centered around the duration of therapy for patients with SAB. Fortunately, the refinement of echocardiography and the creation of new diagnostic criteria have aided in the diagnosis of infective endocarditis in patients with SAB. These advancements have resulted in the development of an algorithm that combines clinical, microbiologic, and echocardiographic findings to stratify patients with SAB into different treatment regimens.

Journal Article↗
PubMed1982

Limited digestion of guinea pig myelin basic protein and its carboxy-terminal fragment (residues 89-169) with Staphylococcus aureus V8 protease.

Staphylococcus aureus V8 protease has been reported to have a strict specificity for cleavage of the Glu-X bond in ammonium bicarbonate (pH 7.9). With myelin basic protein and one of its major peptic fragments (residues 89-169) as substrates, selective cleavage of Asp(32)-Thr(33), Asp(37)-Ser(38), and Glu(118-Gly(119) bonds was observed, as well as the unusual cleavage of the Gly(127)-Gly(128) bond. The Asp-Glu and Glu-Asn bonds in the sequence of Gln-Asp-Glu-Asn-Pro(81-84) were resistant to V8 protease attack. The following peptides were identified as products of limited cleavage of basic protein by V8 protease: (1-32), (1-37), (33-169), (38-169), (33-118), (38-118), (33-127), (38-127), (119-169), and (128-169). Cleavage of the peptic peptide (89-169) yielded fragments (89-118), (89-127), (119-169), and (128-169). All peptides were identified by amino acid analysis, as well as NH2- and COOH-terminal analyses. Time course studies with basic protein showed that V8 protease initially attacked the bonds between Asp(32) and Thr(33) and Asp(37) and Ser(38). With peptide (89-169) the initial cleavage was between Glu(118) and Gly(119). Peptides (89-118) and (89-127) were encephalitogenic in the Lewis rat. The activity of these peptides in the rat confirms the presence of a minor encephalitogenic site in guinea pig basic protein. Peptide (89-127) was encephalitogenic in the guinea pig, as expected, because it contains the intact encephalitogenic site. V8 protease digestion of basic protein yields some interesting new fragments, not previously available for biologic studies.

Amino Acid Sequence↗
PubMed2005

A partial budget model to estimate economic benefits of lactational treatment of subclinical Staphylococcus aureus mastitis.

Subclinical Staphylococcus aureus mastitis is rarely treated during lactation because it is widely believed to be uneconomical, although there are no economic studies that support this view. Partial budgeting was used to develop a deterministic simulation model to estimate the net cost or benefit of antibiotic treatment of subclinical S. aureus mastitis during lactation. Direct and indirect effects of treatment were taken into account, including prevention of clinical flare-ups and contagious transmission. Input variables were based on literature and on 2003-2004 prices in the Netherlands. When contagious transmission of S. aureus was likely (reproductive ratio R = 5.3), 3- and 8-d treatments resulted in an average net profit of 95.62 euros and 142.42 euros, respectively, compared with no treatment. When the probability of S. aureus transmission was low (R = 0.32), the average economic benefit of 3- or 8-d treatment was -21.12 euros and -57.70 euros, respectively. On low-transmission farms, 3-d treatment was profitable when the appropriate cows were selected for treatment using known risk factors for cure. Sensitivity analysis showed that the 6 most influential input variables in the model were chance of bacteriological cure, R, probability of culling, retention pay-off, and cost of antibiotics and bacterial culture. Although the economic outcome of lactational treatment of subclinical S. aureus mastitis is highly herd-, cow-, and strain-dependent, treatment is economically justified in many situations.

Animals↗
PubMed1995

Identifying the patient risk for Staphylococcus aureus bloodstream infections.

Staphylococcus aureus is one of the leading causes of bloodstream infection, and these infections still have a high mortality. In certain clinical situations and for the planning of future prophylactic precautions, it is important to identify patients at risk of S. aureus bloodstream infection. Nearly all patients with S. aureus bloodstream infection have underlying conditions such as cardiovascular disease, renal disease, previous surgery, intravenous drug abuse, or malignancy. The great proportion of patients are over 60 years old and the infection is most often acquired in the hospital. The most common focus is intravascular catheters followed by wounds, skin, lungs, bone and joints, and heart valves. The potential risk factors are nasal carriage, previous hospitalisation, surgery, trauma, haemodialysis, presence of high risk focus, acquisition in an orthopaedic ward, and intravenous drug abuse.

Bacteremia↗
PubMed2006

[Resistance of Staphylococcus aureus isolated from burn wounds to antibiotics].

OBJECTIVE: To determine the colonization rate of Staphylococcus aureus in burn wounds and to assess the variation in the resistance of Staphylococcus aureus strains to antibiotics. MATERIAL AND METHODS: A retrospective study of 72 patients with burn wounds was carried out during 1997 and 2003. Specimens taken from burn wounds at first, fifth, and later every seventh day of hospitalization were placed in transport medium. Isolates were grown on mannitol salt agar. Cultures of Staphylococcus aureus were determined using plasmacoagulase and DNA-ase tests. The resistance of Staphylococcus aureus strains to penicillin, oxacillin, ceftazidime, vancomycin, gentamicin, kanamycin, tobramycin, doxycycline, ciprofloxacin, cefepime, fusidic acid, and clindamycin was determined. The isolated strains of Staphylococcus aureus were tested for resistance to methicillin by performing a disc diffusion method using commercial discs (Oxoid) (5 microg methicillin per disk and 1 microg oxacillin per disk). RESULTS: During 1997-2003, a total of 221 Staphylococcus aureus cultures were isolated from burn wounds. More than one-fourth of all isolated Staphylococcus aureus strains (25.3%) were resistant to methicillin; 64% of methicillin-sensitive Staphylococcus aureus strains were resistant to clindamycin and 28-30% - to gentamicin and kanamycin. The resistance rate of methicillin-resistant Staphylococcus aureus strains to doxycycline, clindamycin, oxacillin, tobramycin, gentamicin, and kanamycin was 78.5-98%. Majority of Staphylococcus aureus strains were non-susceptible to ceftazidime (91-100%); the rate of resistance to clindamycin decreased from 99% to 36%, (p<0.05) and to ciprofloxacin - increased from 55-65% to 81% (p<0.05). CONCLUSIONS: Staphylococcus aureus was the most prevalent pathogen isolated from burn wounds. On the first day of hospitalization Staphylococcus aureus isolates were obtained from 25.3% of patients; 12.5% of patients with burn wounds had methicillin-resistant Staphylococcus aureus at the end of the first week of hospitalization and 66% of patients--after two weeks and later. The resistance of methicillin-susceptible Staphylococcus aureus to gentamicin, tobramycin, and clindamycin decreased. The resistance of methicillin-resistant Staphylococcus aureus to clindamycin decreased and to ciprofloxacin--increased.

Anti-Bacterial Agents↗
PubMed2001

Predisposing factors and outcome of Staphylococcus aureus bacteremia in neutropenic patients with cancer.

Staphylococcus aureus caused 30 of 438 (7%) cases of bacteremia in neutropenic patients with cancer during a 10-year study period. Acute leukemia as an underlying disease and severe oral mucositis were more frequent among patients with Staphylococcus aureus bacteremia (57% vs. 33%, P = 0.01, and 32% vs. 12%, P = 0.006, respectively) than among the 151 patients who had gram-negative bacteremia during the same study period. The most frequent source of Staphylococcus aureus bacteremia was the venous catheter (35% vs. 1%; P = 0.00001). Septic metastases were more frequent in patients with Staphylococcus aureus bacteremia (14% vs. 4%, P = 0.03). Attributable mortality was 10% and overall mortality 23%. Staphylococcus aureus bacteremia remains a significant cause of morbidity and mortality in neutropenic patients with cancer.

Adolescent↗
PubMed2005

A novel method to control the balance of skin microflora. Part 1. Attack on biofilm of Staphylococcus aureus without antibiotics.

BACKGROUND: Staphylococcus aureus (SA) is usually present in atopic dry skin, and not only in regions seriously affected by atopic dermatitis. SA discharges various toxins and enzymes that injure the skin, and forms a biofilm from fibrin fiber and glycocalyx; the biofilm is important for adhesion of SA to the skin and for resistance to anti-microbial agents. Even highly effective moisturizers do not work perfectly on atopic dry skin. Staphylococcus epidermidis (SE) is a major constituent of skin microflora on healthy human skin, and provides protection against the growth of pathogenic bacteria. OBJECTIVES: Since treatment with anti-microbials may lead to re-growth of SA, which grows faster than other Staphylococci and often shows antibiotic resistance, we searched for novel approaches to control the skin-microfloral balance without using conventional anti-microbials. METHOD: Biofilm formation by SA in vitro was observed in detail using scanning electron microscopy. Approximately 500 substances were screened for a selective effect on SA growth and SA biofilm. RESULTS: We found that xylitol inhibited the formation of glycocalyx, and farnesol dissolved fibrin fibers. Farnesol suppressed the growth of only SA, and did not affect that of SE. Xylitol and farnesol synergistically inhibited biofilm formation by SA. CONCLUSION: Xylitol and farnesol have potential for controlling the skin-microfloral balance because of their selective effects and inhibition of biofilm formation. They might provide a useful and safe method to care for skin colonized by SA, without using antibiotics.

Administration, Cutaneous↗
PubMed1992

In vitro adherence of Staphylococcus saprophyticus, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus aureus to human ureter.

Staphylococcus saprophyticus adhered to human ureteral epithelium in vitro. The levels of adherence, which were determined quantitatively with the scanning electron microscope, correlated well with bacterial hemagglutinating activities with sheep erythrocytes (r = 0.9459, P < 0.01). Transmission electron microscopy revealed that the adhering bacteria and the hemagglutinating bacteria possessed similar pili-like structures on their cell surfaces. Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus aureus did not adhere to the epithelium. Only S. aureus adhered markedly to the connective tissue of the ureter, and adhesion of this organism was direct via its cell wall. This adherence test system clearly showed up differences in the abilities of these staphylococcal species to adhere to the urinary tract.

Bacterial Adhesion↗
PubMed2004

Evaluation of polymerase chain reaction, conventional and MRSA screen latex agglutination methods for detection of methicillin-resistant, -borderline and -susceptible Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA), is difficult and expensive to treat, therefore early screening is essential. Several phenotypic and genotypic methods are used to detect MRSA; however, the method of choice remains problematic. We have evaluated four phenotypic methods, broth microdilution (MIC), oxacillin disk agar diffusion (ODD), oxacillin screening salt agar (OSS), and a new rapid phenotypic (MRSA screen latex agglutination, MSLA) with the genotypic gold standard of PCR mecA detection to determine the most appropriate method for routine laboratory use. We randomly collected 203 S. aureus isolates from patients and carriers at two hospitals in Thailand. Using MIC method, three sub-groups were differentiated from among these isolates, namely MRSA (106 isolates), borderline-resistant S. aureus (BRSA) (65 isolates), and methicillin-susceptible S. aureus (MSSA)(32 isolates). A total of 10 methicillin-resistant S. epidermidis (MRSE) isolates were also included. The sensitivity and specificity of MIC, ODD, OSS, and MSLA were 99 and 96, 100 and 97, 100 and 97, and 100 and 100%, respectively. Our study indicated that ODD is still appropriate for routine laboratory. MSLA had the highest sensitivity and specificity and is rapid but expensive, so is the most appropriate method for emergency cases. MIC method was better for BRSA detection and OSS method was more appropriate for screening clinical specimens and carriers.

Humans↗
PubMed2005

[Are we being threatened by multiresistant strains of Staphylococcus aureus?].

Multiresistant strains of Staphylococcus aureus (MRSA) are characterized by their virulence and clinical resistance to all known beta-lactam antibiotics. Furthermore, the representatives of most other classes of antibiotics are also proving to be no longer effective. While infections with the usual S. aureus strains can mostly be readily managed with penicillinase-resistant penicillins, the rescue antibiotic vancomycin, as also teicoplanin, in combination with, for example fosfomycin, are required in the treatment of MRSA and S. epidermidis infections. Since infections with S. aureus/MRSA are usually of endogenous origin, decolonization with mupirocin-containing nasal ointment applied as a prophylactic measure in patients with high colonization rates and/or immunosuppression, is of major importance. The best protection against further spread of highly resistant germs, such as MRSA is, in particular, profession hygiene management.

Aged↗
PubMed2004

Antibody-directed photodynamic therapy of methicillin resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a world-wide public health problem, causing nosocomial and community-acquired infections. Furthermore, MRSA is increasingly resistant to many conventional antimicrobials, so there is a real need to develop alternative approaches for MRSA decolonization and treatment. Previously, we have demonstrated that MRSA can be killed with an immunoglobulin G (IgG)-SnCe6 conjugate and red light, but effectiveness was dependent on the particular strain and the growth phase. In this investigation, we used an antibody raised against MRSA to make an Ab-SnCe6 conjugate capable of targeting many MRSA strains in all growth phases. To suspensions of important epidemic MRSA, each grown to stationary, lag, or exponential phase, the Ab-SnCe6 conjugate was added and samples exposed to red light. Survivors were then enumerated. This treatment was very effective at killing all the different MRSA strains tested, in all growth phases. The Ab-SnCe6 conjugate was able to kill EMRSA-16 selectively in a mixed suspension of EMRSA-16 and Escherichia coli, and was much better at killing EMRSA-16 than a coagulase-negative staphylococcus, S. epidermidis. These results demonstrate that photodynamic therapy of MRSA is very effective when the photosensitizer is targeted to the pathogen using a suitable antibody and may be a good candidate for a novel treatment of MRSA infections.

Humans↗
PubMed1993

Detection and characterization of mupirocin resistance in Staphylococcus aureus.

Fourteen mupirocin-resistant Staphylococcus aureus strains were isolated over 18 months; 12 exhibited low-level resistance, while two showed high-level resistance. Highly mupirocin-resistant strains contained a large plasmid which transferred mupirocin resistance to other S. aureus strains and to Staphylococcus epidermidis. This plasmid and pAM899-1, a self-transferable gentamicin resistance plasmid, have molecular and biologic similarities.

Conjugation, Genetic↗
PubMed1997

Clonal heterogeneity, distribution, and pathogenicity of methicillin-resistant Staphylococcus aureus.

Four thousand eighty-eight Staphylococcus aureus isolates obtained from patients hospitalised in a university clinic and four community hospitals over a period of one year were screened for methicillin resistance. A resistance rate of 5% was detected among initial isolates. Distribution of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus showed an increased prevalence of MRSA in clinically significant specimens such as blood, central venous catheter tips, bronchial secretions, and wound secretions. Typing of 110 MRSA strains (initial isolates) by macrorestriction analysis of chromosomal DNA revealed 26 different genotypes that could be divided into five epidemic and 21 sporadic strains. More than 50% of all isolates belonged to one type that was confirmed to be closely related to the "southern-German" epidemic strain. Production of virulence factors such as enterotoxin A-D and toxic shock syndrome-toxin 1 among MRSA strains (initial isolates) occurred in ten of 26 different MRSA types. A strong correlation between genotype and toxin production was demonstrated.

Clone Cells↗