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PubMed2002

Proteolytic activity of Staphylococcus aureus strains isolated from the colonized skin of patients with acute-phase atopic dermatitis.

Staphylococcus aureus strains isolated from the colonized skin lesions of 26 patients with acute-phase atopic dermatitis were reported to produce various extracellular proteolytic enzymes. Using the skim-milk-agar culture plating method, it was shown that 97% of the strains (65 of 67 examined) produced proteolytic activity, with 61% (42 strains) producing activity comparable to that of the proteolytically hyperactive reference strain Staphylococcus aureus V8. This observation was confirmed by azocasein degradation with culture supernatants, which indicated that 91% of the strains produced extracellular proteinases and 43% exceeded the 2% activity threshold of the reference strain. Control strains were isolated from the nose vestibules of 18 healthy carriers; the proteolytic activity of these strains never exceeded 2.5% of the activity of the reference strain. In 54% of the patients examined ( n=14), the activity of the strains was higher than that determined for the isolates from the control group. The combined use of assays incorporating azocasein and a synthetic chromogenic substrate, N-CBZ-Phe-Leu-Glu- pNA, showed that two staphylococcal enzymes, Staphylococcus aureus metalloproteinase (SAMP) and Staphylococcus aureus serine proteinase (SASP), contributed to the total proteolytic activity released by the strains examined. The contribution of each of the two enzymes varied greatly between different isolates. The undamaged skin of the patients was not colonized with Staphylococcus aureus. The presence of several strains with atypical proteinase characteristics was also reported, suggesting the possible involvement of enzymes other than serine- and metallo-proteinases in the proteolytic activity of Staphylococcus aureus. Taken together, the results of the study imply that staphylococcal proteinases may contribute to the pathogenicity of atopic dermatitis.

Acute Disease↗

PubMed2004

Comparison of the BBL CHROMagar Staph aureus agar medium to conventional media for detection of Staphylococcus aureus in respiratory samples.

Screening for Staphylococcus aureus has become routine in certain patient populations. This study is the first clinical evaluation of the BBL CHROMagar Staph aureus agar (CSA) medium (BD Diagnostics, Sparks, Md.) for detection of S. aureus in nasal surveillance cultures and in respiratory samples from cystic fibrosis (CF) patients. S. aureus colonies appear mauve on CSA. Other organisms are inhibited or produce a distinctly different colony color. S. aureus was identified from all media by slide coagulase, exogenous DNase, and mannitol fermentation assays. Susceptibility testing was performed using the agar dilution method. A total of 679 samples were evaluated. All samples were inoculated onto CSA. Nasal surveillance cultures were inoculated onto sheep blood agar (SBA) (BD Diagnostics), and samples from CF patients were inoculated onto mannitol salt agar (MSA) (BD Diagnostics). Of the 679 samples cultured, 200 organisms produced a mauve color on CSA (suspicious for S. aureus) and 180 were positive for S. aureus on SBA or MSA. Of 200 CSA-positive samples 191 were identified as S. aureus. Nine mauve colonies were slide coagulase negative and were subsequently identified as Staphylococcus lugdunensis (one), Staphylococcus epidermidis (three), Staphylococcus haemolyticus (one), and Corynebacterium species (four). CSA improved the ability to detect S. aureus by recovering 12 S. aureus isolates missed by conventional media. Of the 192 S. aureus isolates recovered, 122 were methicillin susceptible and 70 were methicillin resistant. Overall, the sensitivity and specificity of CSA in this study were 99.5 and 98%, respectively. There was no difference in the performance of the slide coagulase test or in susceptibility testing performed on S. aureus recovered from CSA compared to SBA or MSA. Our data support the use of CSA in place of standard culture media for detection of S. aureus in heavily contaminated respiratory samples.

Bacteriological Techniques↗

PubMed1986

In vitro [3H]-erythromycin binding to Staphylococcus aureus.

Characteristics of erythromycin binding to Staphylococcus aureus were determined by using kinetics and equilibrium binding experiments. Both methods yielded identical values of the dissociation constant, i.e. 0.1 muM. This value was in accord with that found with a bacterial extract of ribosomes which are the organelles where erythromycin exerts its action. This good agreement shows that the dissociation constant of erythromycin determined with intact bacteria is a good reflect of specific bacterial receptors of macrolides, i.e. ribosomes. In addition, mechanism of uptake of the antibiotic by Staphylococcus aureus was investigated. Passive diffusion process was shown to be mainly responsible for this phenomenon.

Erythromycin↗

PubMed1994

The current spectrum of Staphylococcus aureus infection in a tertiary care hospital.

Staphylococcus aureus remains a prominent cause of community- and hospital-acquired infection. This study reviewed 162 cases of S. aureus infection occurring in 120 adults who were hospitalized at a Veterans Affairs Medical Center and referred for consultation to the Infectious Disease Service. There were 37 cases of skin and soft tissue infection, 5 pyomyositis, 34 osteomyelitis, 13 septic arthritis, 19 pneumonia, 3 empyema, 5 pyelonephritis, 37 vascular infection, 3 epidural abscess, and 6 miscellaneous infections. Bacteremia was documented in 56 of 119 (47%) cases in which blood cultures were obtained, indicating the serious nature of the infections in many cases. Staphylococcus aureus is widely prevalent in healthy persons. Given its ubiquity and the capacity to cause a broad array of infections, an effective host response must play an important role in preventing infection. This host response is immunologically nonspecific, in that it depends upon the effectiveness of mechanical barriers to invasion and, once invasion takes place, the interaction of PMN, complement, and antibody that is probably present in serum of all immunologically competent adults rather than sensitization of B or T lymphocytes by any identifiable antigens specific to S. aureus. Analysis of the present cases calls attention to S. aureus as an opportunistic pathogen, 1 that only infrequently causes serious infection in otherwise healthy persons. Nearly every patient in this series had 1 or more medical condition thought to predispose to infection; 279 such conditions were identified, representing an average of 2.3 per person. A break in the natural barrier to infection was also present in the majority of cases, for example, trauma, wound, or pre-existing decubitus ulcer in skin and soft tissue infections; endotracheal tube in pneumonia; and a catheter bypassing urethra or skin in urinary and vascular infections, respectively. The tendency for patients to be infected with S. aureus repeatedly (mean number of infections, 1.4 per patient) reflects the chronicity of many predisposing factors and, perhaps, of colonization as well. Staphylococcus aureus has a special predilection to cause infections involving prosthetic devices, perhaps related to its affinity for fibronectin, laminin, and other serum proteins that can mediate attachment to foreign material; 46 of 162 (28%) infections were associated with the presence of a foreign body. Such infections are difficult to eradicate with antibiotic therapy alone, perhaps because of a change in the metabolic state of adherent bacteria, and removal of the foreign body is generally required for cure.(ABSTRACT TRUNCATED AT 400 WORDS)

Abscess↗

PubMed1982

Structural changes induced by subinhibitory concentrations of fosfomycin on Staphylococcus aureus and Bacillus cereus.

Exposure of Staphylococcus aureus ATCC 6538 and Bacillus cereus ATCC 11778 to 1/2 MIC fosfomycin for 3 and 6 h was studied by transmission and scanning electron microscopy. After 3 h, a loss of density and irregularity of shape in the septum was noted, while after 6 h a delayed separation of newly formed cells was observed in both species. In Staphylococcus aureus this resulted in the formation of chains of intact cells and cells in lysis. In Bacillus cereus, it produced filamentous forms with multiple septa. the differences between the effects observed at 3 h and 6 h may be due to time-related variations in cell permeability to fosfomycin, or to the existence of indirect mechanisms enabling fosfomycin to interfere with the enzymatic activity regulating the normal separation of cells, or to a combination of these factors.

Anti-Bacterial Agents↗

PubMed2026

First UK use of bacteriophage therapy with DAIR for chronic Staphylococcus aureus prosthetic joint infection.

BACKGROUND: Chronic Staphylococcus aureus prosthetic joint infection (PJI) remains difficult to manage when surgical revision and long-term antibiotics are not feasible. Bacteriophage therapy is emerging as a potential adjunct, though experience in orthopedic infections, particularly in the United Kingdom, is limited. CASE SUMMARY: We report the first UK case of intra-articular bacteriophage therapy administered alongside debridement, antibiotics, and implant retention (DAIR) for chronic methicillin-sensitive Staphylococcus aureus knee PJI. An 81-year-old man with multiple comorbidities developed persistent infection following revision knee arthroplasty, with recurrent sinus formation despite multiple surgical washouts and prolonged suppressive antibiotics. Major revision surgery and amputation were not viable options. Following a multidisciplinary review through the UK Clinical Phage Network, targeted phage therapy was pursued as salvage treatment. Phage susceptibility testing identified an active lytic phage (ISP). The patient underwent open DAIR with intra-articular phage administration, adjunctive local antibiotics, short-course intravenous antimicrobials, and subsequent oral suppressive therapy. Two further intra-articular phage doses were administered postoperatively. Initial sinus closure occurred, but recurrence developed within 4 weeks. At 18 months, symptoms were partially improved with better mobility and reduced inflammation, though one sinus tract persisted. No significant adverse effects were observed. Whole-genome sequencing of pretreatment isolates demonstrated a predominantly ST5 S. aureus genotype with conserved biofilm-associated virulence genes and limited antimicrobial resistance in addition to clonal diversification consistent with chronic biofilm infection. CONCLUSION: This case demonstrates the feasibility and safety of intra-articular phage therapy during DAIR in a UK setting but highlights biological, logistical, and pharmacological factors that may limit efficacy in advanced chronic PJI.

Staphylococcus aureus↗

PubMed1984

Complications associated with Staphylococcus aureus bacteremia.

Thirty-nine consecutive Staphylococcus aureus bacteremias were reviewed with particular attention to complications. Thirty-four (87%) of the bacteremias were nosocomial, with intravascular catheters (20 episodes) and dialysis-access sites (six episodes) the most common sources. Complications developed in 36% (14/39) of all bacteremias and in 30% (6/20) of those that were catheter-associated. Acute complications (shock, adult respiratory distress syndrome, disseminated intravascular coagulation) occurred in six patients and were fatal in four. In nine patients metastatic suppurative complications developed, six at sites of preexisting abnormalities. There were no episodes of endocarditis. Most patients received prolonged antibiotic therapy, and the majority of all suppurative complications required surgical intervention. Staphylococcus aureus bacteremia, even when not associated with endocarditis, is a cause of considerable morbidity and mortality in hospitalized patients.

Adult↗

PubMed1992

Restriction endonuclease analysis of Staphylococcus aureus plasmid DNA from three continents.

Staphylococcus aureus isolates (n = 1201) from 20 centers in Europe, the USA and Brazil were evaluated for the presence of epidemiologic markers. Plasmid typing and restriction endonuclease analysis of plasmid DNA confirmed the presence of an apparently identical plasmid in 13% of clinical isolates. The plasmid was recovered from all 20 hospitals studied, with an overall frequency of greater than 10% on each of the three continents. Since relatively few staphylococcal plasmids may be shared by epidemiologically unrelated strains, there are inherent limitations to this otherwise useful technique. Additionally, these data demonstrate the importance of including unrelated strains of Staphylococcus aureus from the local region as controls when molecular typing methods are performed.

Brazil↗

PubMed2004

[Study on the resistance of methicillin-resistant staphylococcus aureus to iodophor and chlorhexidine].

OBJECTIVE: To study the resistance of methicillin-resistant staphylococcus aureus (MRSA), an indicator used in hospitals. METHODS: We used minimal inhibitory concentrations (MIC) of iodoph and chlorhexidine to MRSA, methicillin-sensitive staphylococcus aureus (MSSA) and staphylococcus aureus ATCC6538. RESULTS: Obvious difference between MRSA and MSSA the MIC of Iodophor was noticed. Among MICs, 5.3% MRSA strains were 2-folds and 28.9% MRSA strains were 1.5 fold more than staph. aureus ATCC6538, while the MIC of 11.1% MSSA strains raised 1.5 fold than ATCC6538. The MIC of 83.3% MSSA strains were the same to staph. aureus ATCC6538. The MIC of chlorhexidine to MRSA, MSSA and staphylococcus aureus ATTC6538 were similar to each other. CONCLUSION: Results showed that some MRSA were more resistant to Iodophor than staph. aureus ATCC6538, but remained the same resistance to Chlorhexidine. Thus the concentration of Iodophor should be raised when the resistant strains were isolated.

Anti-Infective Agents↗

PubMed2005

In vitro activity of sodium-benzoate against isolates of methicillin-resistant Staphylococcus aureus.

BACKGROUND: Worldwide, methicillin-resistant Staphylococcus aureus (MRSA) rates have increased dramatically during the last decades. Sodium benzoate (SB) is a chemical substance that is used for preparing food and drinks and in the treatment of some metabolic (urea cycle disorders and hepatic coma) diseases. No studies were found which focussed on the effects of SB in MRSA infections. The aim was to determine in vitro activity of sodium benzoate against MRSA clinical isolates. METHODS: In this study, MIC for SB in 36 MRSA and 29 methicillin-sensitive Staphylococcus aureus (MSSA) isolates were determined by a broth microdilution method recommended by the National Committee for Clinical Laboratory Standards. RESULTS: The MIC at which all of the MRSA and MSSA strains were inhibited was at 32 microg/ml and higher concentrations. CONCLUSION: Sodium benzoate showed good in vitro activity against clinically relevant MRSA and MSSA isolates. It is suggested in this study that this cheap substance, which has been used for systemic and local treatment of infection in humans, may be used alternatively for the treatment of MRSA infections. However, it is clear that more comprehensive and in vivo studies are needed to further elucidate the activity of SB against MRSA infections.

Dose-Response Relationship, Drug↗

PubMedDate not supplied

Emergence of mupirocin-resistant Staphylococcus aureus in chronic peritoneal dialysis patients using mupirocin prophylaxis to prevent exit-site infection.

OBJECTIVE: To determine the prevalence of the carriage of Staphylococcus aureus (SA), methicillin-resistant Staphylococcus aureus (MRSA), and mupirocin-resistant Staphylococcus aureus (MuRSA) in chronic peritoneal dialysis (CPD) patients after 4 years of prophylactic mupirocin application to the exit site, in a peritoneal dialysis unit. METHODS: Three swabs were collected from the nares, axillae/groin, and exit site, respectively, from 149 patients on CPD between May and July 2001. All swabs were cultured on solid selective agar (mannitol salt agar) and in mannitol salt broth. Staphylococcus aureus isolates were tested for methicillin resistance using oxacillin screening plates, and mupirocin resistance using E-test strips. Low-level MuRSA was defined as minimum inhibitory concentration (MIC) of 4 mg/mL or more, and high-level MuRSA as MIC of 256 mg/mL or more. RESULTS: Staphylococcus aureus was isolated from 26 (17%) patients (25 from nares/axilla/groin, and 1 from the exit site). High-level MuRSA was isolated from 4 patients (3% of the total study population; 15% of total SA isolates). No MRSA was detected. One patient with high-level MuRSA had peritonitis due to SA, resulting in treatment failure and catheter loss, soon after the swabs were collected for the study. CONCLUSION: We report the emergence of high-level MuRSA in CPD patients after a 4-year practice of continuous use of mupirocin in a small number of patients in our unit. Our results may have significant implications for the future practice of prophylactic use of mupirocin by CPD patients to prevent exit-site infection.

Adult↗

PubMedDate not supplied

[The carriage of Staphylococcus aureus among different population groups].

The level of carriage of Staphylococcus aureus in three biotopes (nose, fauces, hand skin) and categories of carriers among students and teachers of the Medical Institute, medical personnel of surgical department and maternity hospital as well as the workers of combine building plant have been studied. The higher percentage of Staphylococcus aureus carriers was established in the nasal cavity of the maternity hospital personnel (p < 0.001) and on the hand skin of the personnel of surgical stationary (p < 0.05) as compared to the students and teachers. Carriage frequency of Staphylococcus aureus among the workers several times exceeded its level in the control group. The strains of the third phage group predominated among the personnel of surgical department, those of the second and fourth phage, groups, among the maternity hospital workers. Representatives of the second phage group were isolated in the plant workers. High level of carriage among the workers creates preconditions for the development of purulent diseases of the hand and fingers after microtraumas at the plant. All this dictates a necessity to eliminate Staphylococcus aureus in the carriers of all three biotopes.

Adolescent↗

PubMed2000

[Study on uptake of fluoroquinolones by Staphylococcus aureus].

This study aimed to investigate the mechanism of Staphylococcus aureus' resistance to fluoroquinolones. The uptake of lomefloxacin, ofloxacin by Staphylococcus aureus and the effect of CCCP on the uptake were studied by the fluorescence method. The uptake of lomefloxacin, ofloxacin by sensitive organisms is higher than that by resistant organisms; CCCP had different influences on different organisms, but no significant difference between the effects of CCCP on sensitive strains and on resistant strains was noted. The uptake of lomefloxacin, ofloxacin by SA2-16 was much lower than that by SA2-16's parent, and after the addition of CCCP, the uptake of both quinolones by SA2-16 increased rapidly, but the concentration did not reach its parent's concentration in stable condition. These results indicate that the decreasing of the uptake of fluoroquinolones is one of the mechanisms responsible for Staphylococcus aureus to resistance fluoroquinolones, and as a mechanism of resistance to drugs, it plays different roles in different strains.

Anti-Infective Agents↗

PubMed2006

Isolates with low-level vancomycin resistance associated with persistent methicillin-resistant Staphylococcus aureus bacteremia.

Low-level vancomycin-resistant Staphylococcus aureus (vancomycin-intermediate S. aureus [VISA] and heterogenous VISA [hVISA]) is increasingly reported and leads to glycopeptide treatment failure. Various phenotypic features have been reported for these isolates, but the genetic changes leading to hVISA and VISA have yet to be clearly determined. We assessed phenotypic, antibiotic resistance, and genomic changes by using genomic DNA microarray comparison and sequencing of selected loci in five pairs of clinical hVISA/VISA strains and the initial methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained prior to vancomycin therapy. The isolates were from adult patients in Australia and New Zealand who had persistent MRSA bacteremia (>7 days) while receiving vancomycin therapy. In all cases, the initial isolates were found to be fully vancomycin-susceptible Staphylococcus aureus (VSSA). The hVISA/VISA phenotype was associated with increased cell wall thickness, reduced autolytic activity in four of five hVISA/VISA strains, and a striking reduction in biofilm formation compared to the parent strains in all pairs. All five pairs appeared to be isogenic, and genomic DNA microarray comparison suggested that major genetic changes are not required for the development of the resistant phenotype in these strains. No sequence differences were found in the agr locus or the tcaRA genes for any pair, but a marked reduction in RNAIII expression was found in four pairs. In summary, hVISA/VISA arises from fully VSSA during persistent infection that fails to respond to glycopeptide therapy and is associated with significant phenotypic changes, including a marked reduction in biofilm-forming ability. These clinically derived pairs of isolates will be a useful resource to elucidate the genetic mechanism of resistance in hVISA/VISA strains.

Bacteremia↗

PubMed1971

Electron microscopy during release and purification of mesosomal vesicles and protoplast membranes from Staphylococcus aureus.

The mesosomes of log-phase Staphylococcus aureus ATCC 6538P and Staphylococcus aureus phage-type 80/81, as seen in situ in ultrathin sections, were of the vesicular type. The constituent vesicles ranged from 35 to 50 nm in diameter when the glutaraldehyde-osmium-uranium-lead sequence of fixation and staining was used. During protoplasting in hypertonic buffer containing a muralytic enzyme, vesicles of the same size were extruded and required magnesium ion to maintain structural integrity. The vesicles, purified from the protoplasting supernatant medium by density gradient centrifugation, maintained size and configuration in a homogeneous preparation. Cytoplasmic membranes, produced by osmotic shock and nuclease treatment of protoplasts, were similarly concentrated in gradients. However, they were not free of membrane-associated ribosomes nor of mesosomal vesicles except when prepared in the absence of magnesium.

Acetates↗

PubMed1994

Rhabdomyolysis associated with bacteremic pneumonia due to Staphylococcus aureus.

A case of rhabdomyolysis associated with bacteremic pneumonia due to Staphylococcus aureus is reported. A 58-year-old man was admitted because of severe left lobar pneumonia, and presented myoglobinuria on admission. The serum creatine phosphokinase level was transiently elevated and myoglobinuria were disclosed. Sputum and venous blood cultures grew Staphylococcus aureus. Rhabdomyolysis has rarely been reported in cases of bacterial infection, especially those due to Staphylococcus aureus. This case might be an extremely rare case of rhabdomyolysis complicating Staphylococcus aureus bacteremia following severe left upper lobar pneumonia.

Bacteremia↗

PubMed1991

Nucleotide sequence and phylogeny of a chloramphenicol acetyltransferase encoded by the plasmid pSCS7 from Staphylococcus aureus.

The nucleotide sequence of the chloramphenicol acetyltransferase gene (cat) and its regulatory region, encoded by the plasmid pSCS7 from Staphylococcus aureus, was determined. The structural cat gene encoded a protein of 209 amino acids, which represented one monomer of the enzyme chloramphenicol acetyltransferase (CAT). Comparisons between the amino acid sequences of the pSCS7-encoded CAT from S. aureus and the previously sequenced CAT variants from S. aureus, Staphylococcus intermedius, Staphylococcus haemolyticus, Bacillus pumilis, Clostridium difficile, Clostridium perfringens, Escherichia coli, Shigella flexneri, and Proteus mirabilis were performed. An alignment of CAT amino acid sequences demonstrated the presence of 34 conserved amino acids among all CAT variants. These conserved residues were considered for their possible roles in the structure and function of CAT. On the basis of the alignment, a phylogenetic tree was constructed. It demonstrated relatively large evolutionary distances between the CAT variants of enteric bacteria, Clostridium, Bacillus, and Staphylococcus species.

Amino Acid Sequence↗

PubMed2005

[Epidemiology of methicillin-resistant Staphylococcus aureus at the Kenézy Hospital between 1999 and 2004].

INTRODUCTION: The prevention of the spread of multiresistant microorganisms, especially methicillin-resistant Staphylococcus aureus is the main problem of epidemiology in our era. Kenézy Hospital was among the firsts to deal with the laboratory diagnosis of methicillin-resistant Staphylococcus aureus infection in Hungary, looking for the possibilities to isolate, and detect methicillin-resistant Staphylococcus aureus in patients (colonised and infected), and to provide for them proper treatment and complex management. AIMS: The authors aimed to help the work of infection control professionals by sharing their experience and through the analysis of their data. METHODS: The authors analysed the data on the incidence of infection of methicillin-resistant Staphylococcus aureus positive patients from 1999 at the Kenézy Hospital and investigated the effect of infection control policies on the incidence of infection. RESULTS: On the hospital level the lowest frequency of methicillin-resistant Staphylococcus aureus positive patients was found in 2003. The authors identified the Rehabilitation, the Traumatology and the Intensive Care Department as high risk units. The higher incidence was caused by the endemic occurrence of the disease at the specific wards. The methicillin-resistant Staphylococcus aureus infections became more severe every year, demonstrated by the increasing positivity rate of the blood cultures. Based on the identification of the most frequent phage types in each year, an epidemic strain, unlike in England, could not be found at the Kenézy Hospital. CONCLUSIONS: The number of methicillin-resistant Staphylococcus aureus positive patients at an institute depends on the institute's efforts to effectively apply microbiological screening. At a department where methicillin-resistant Staphylococcus aureus is endemic, elimination of the agent and that of the endemia are difficult tasks for the infection control team.

Cross Infection↗