Staphylococcus infection complicating the application of a supracondylar nail to a fracture proximal to a total knee arthroplasty.
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Bone Nails↗
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Results for “STAPHYLOCOCCUS INFECTIONS”
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Specific roles of alpha-toxin and beta-toxin during Staphylococcus aureus corneal infection.
Staphylococcus aureus corneal infection results in extensive inflammation and tissue damage. Our previous studies of bacterial mutants have demonstrated a role for alpha-toxin in corneal virulence. This study analyzes, by genetic rescue experiments, the virulence of mutants affecting alpha-toxin and beta-toxin activity and demonstrates the ocular toxicity of these purified staphylococcal proteins. Three types of isogenic mutants were analyzed: (i) mutants specifically deficient in alpha-toxin (Hla) or beta-toxin (Hlb), (ii) a mutant deficient in both Hla and Hlb, and (iii) a regulatory mutant, deficient in the accessory gene regulator (agr), that produces reduced quantities of multiple exoproteins, including alpha- and beta-toxins. Plasmids coding for Hla and Hlb (pDU1212 and pCU1hlb, respectively) were used to restore toxin activity to mutants specifically deficient in each of these toxins. Either corneas were injected intrastromally with logarithmic-phase S. aureus or purified alpha- or beta-toxins were administered to normal eyes. Ocular pathology was evaluated by slit lamp examination and myeloperoxidase activity of infiltrating polymorphonuclear leukocytes. Corneal homogenates were cultured to determine the CFU per cornea. Eyes infected with the wild-type strain developed significantly greater corneal damage than eyes infected with Agr-, Hlb-, or Hla- strains. Epithelial erosions produced by parent strains were not produced by Agr- or Hla- strains. Hlb+ strains, unlike Hlb- strains, caused scleral edema. Plasmid pDU1212 restored corneal virulence to strain DU1090 (Hla-), and plasmid pCU1hlb restored corneal virulence to strain DU5719 (Hlb-). Application of purified alpha-toxin produced corneal epithelial erosions and iritis, while application of beta-toxin caused scleral inflammation. These studies confirm the role of alpha-toxin as a major virulence factor during S. aureus keratitis and implicate beta-toxin, a mediator of edema, as a lesser contributor to ocular damage.
Animals↗
The clinical spectrum of Staphylococcus aureus pulmonary infection.
Staphylococcus aureus causes serious pulmonary infections in adults. Prior descriptions of this entity have depended on diagnosis of expectorated sputum cultures that are often contaminated. To better characterize this infection, we retrospectively reviewed the medical records of 31 adults with S aureus pulmonary infection diagnosed by culture specimens uncontaminated by the upper respiratory flora. Our results support the concept that S aureus pulmonary infections usually occur in older adults (sixth decade or older) with concomitant illnesses that are typically nosocomial. However, in contrast to previous reports, the chest roentgenograms in these patients typically showed multilobar infiltrates (60 percent), predominantly in the lower lobes (64 percent), and often bilateral (48 percent). Pleural involvement (48 percent) was more common than previously reported, and abscess formation (16 percent) occurred infrequently. Sputum cultures were found to be sensitive but nonspecific diagnostic tools. Despite antibiotic therapy, reinfection occurred in 10 percent of patients and the mortality rate was 32 percent.
Adult↗
[Antioxidants and immunomodulating action of antibiotics and antibiotic-treated erythrocytes in staphylococcal infections].
Staphylococcus infection inhibited the T-dependent immune response, increased the serum levels of the lipid peroxidation products (LPP) i.e. fatty acid diene conjugates and malonic aldehyde and lowered the activity of the antioxidant system enzymes (ASE) i.e. superoxide dismutase and glutathione reductase in erythrocytes. After administration of amikacin or cephalexin the immunosuppressive effect induced by the staphylococci increased while the LPP content and the ASE activity in the infected host did not change. After injection of erythrocytes extracorporeally treated with the antibiotics the immune response increased, the LPP content decreased and the ASE activity increased. The free antibiotics increased the excretion of suppressing cytokines by glass adherent spleen cells. The antibiotic-treated erythrocytes induced the excretion of low molecular weight helper cytokines and high molecular weight antioxidant factors by the adherent spleen cells.
Adjuvants, Immunologic↗
Community-acquired methicillin resistant Staphylococcus aureus skin infection.
Staphylococcus aureus is one of the most common pathogens in skin and soft tissue infections, as well as in potentially serious nosocomial infections in patients who acquire it when hospitalized. Penicillin was introduced in the 1940's as an effective treatment against S. aureus. However, shortly after penicillin's introduction, penicillin resistance to S. aureus emerged due to a plasmid-mediated beta-lactamase enzyme. In 1959, a semisynthetic penicillin, methicillin was introduced to overcome the resistance problem. However, within a year, bacteria resistant to methicillin and other penicillinase stable beta-lactams, were present. Worldwide emergence of methicillin-resistant S aureus (MRSA) was established by the 1980's. Since that time, MRSA has become widespread in hospitals and long-term care facilities around the world, accounting for numerous nosocomial infections. Recently, there has been an alarming increase in the incidence of community-acquired MRSA (CA-MRSA). Patients with CA-MRSA began to be reported in the early 1990's and its prevalence has continued to increase. This paper summarizes the current information known about CA-MRSA as it relates to skin infections including populations at risk, clinical presentation, and treatment options.
Community-Acquired Infections↗
Kinin receptor expression during Staphylococcus aureus infection.
An inappropriate host response to invading bacteria is a critical parameter that often aggravates the outcome of an infection. Staphylococcus aureus is a major human Gram-positive pathogen that causes a wide array of community- and hospital-acquired diseases ranging from superficial skin infections to severe conditions such as staphylococcal toxic shock. Here we find that S aureus induces inflammatory reactions by modulating the expression and response of the B1 and B2 receptors, respectively. This process is initiated by a chain of events, involving staphylococcal-induced cytokine release from monocytes, bacteria-triggered contact activation, and conversion of bradykinin to its metabolite desArg(9)bradykinin. The data of the present study implicate an important and previously unknown role for kinin receptor regulation in S aureus infections.
Antigens, Bacterial↗
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↗
[Current treatment of Staphylococcus aureus infections].
The Staphylococcus aureus infections seen in general practice still respond relatively well to the usual treatments, including penicillin M, first generation cephalosporins or synergistins. Those seen in hospitals are highly resistant to oxacillin (14 to 43 h depending on individual hospital units) and should be treated from the start with major antistaphylococcal drugs, such as vancomycin, fosfomycin in combination therapy or pefloxacine.
Anti-Bacterial Agents↗
Can the association of athymic mice (Han:NMRI-nu) with Staphylococcus sciuri prevent infection with Staphylococcus aureus? Experiences from a field study.
An attempt was made to prevent the introduction of Staphylococcus aureus into a newly established colony of Han:NMRI-nu mice by means of preassociation with the rodent-specific Staphylococcus sciuri. Despite the successful colonization of the mice with S. sciuri the establishment of S. aureus into the colony was not impeded, and abscesses were observed with an increasing frequency until the end of the study. Random samples revealed the phage pattern 3A/3C/55/71 or very similar ones. A caretaker was identified as a possible vector of transmission, since he was found to be colonized with this S. aureus phage type previous to the outbreak. Finally, the later occurrence of Citrobacter freundii and Pseudomonas aeruginosa serovar P10 in the colony led to the decision to give it up after 21 months of existence.
Animals↗
Pathogenesis and management of Staphylococcus epidermidis 'plastic' foreign body infections.
Staphylococcus epidermidis infections on foreign bodies made of plastic are caused by special and complex mechanisms. The staphylococcal cells are able to adhere to and grow on polymer surfaces in vivo and in vitro. In the course of colonization they produce an extracellular substance ('slime') which eventually covers them. It is thought that the staphylococcal slime has several biological functions, including promoting adhesion and protection against both antibiotics and host defence mechanisms. In patients, the removal of a colonized device should be accompanied by the parenteral administration of highly effective antistaphylococcal drugs, such as vancomycin.
Adhesiveness↗
Evaluation of three techniques for documenting Staphylococcus epidermidis vascular prosthetic graft infections.
Staphylococcus epidermidis (S. epidermidis) vascular prosthetic graft infections are notoriously hard to detect. Three different techniques of determining whether vascular prosthetic grafts were infected using a dog model were evaluated. Aortic angiograms were compared with nuclear magnetic resonance (NMR) imaging and systemic norepinephrine (NE) kinetics to determine if either newer technique would be more reliable than standard angiograms. Twelve dogs were randomized to control (n = 6) or infected groups (n = 6). All dogs had a 5 cm section of their infrarenal aorta replaced with knitted Dacron vascular prosthetic graft. The grafts in the infected group were contaminated by soaking them in a broth containing S. epidermidis. NE production and clearance rates were calculated for all animals after an infusion of 3H-NE using the steady-state radionuclide tracer methodology. One week following graft insertion, dogs were reanesthetized, and the 3H-NE infusion and measurements were repeated. Standard angiograms and NMR imaging were also performed. Once all tests were performed, the prosthetic grafts were removed for cultures. Comparisons between the initial and final norepinephrine measurements for each group were made using the nonparametric Wilcoxon two-sample test, while comparisons between the groups were made by chi square or the Student's t test. Angiogram results were similar for control and infected animals. Angiograms missed disruption of the proximal anastomosis found in three of the six infected dogs at graft removal. None of the six control animals, while five of the six infected animals, had localized areas of high signal intensity on NMR imaging (P less than 0.01) suggesting abscess formation.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Staphylococcus--an agent of nosocomial infections].
Staphylococcus is an important agent of nosocomial infection, especially: urinary tract infections, pneumonia and intraabdominal infections in surgery. The most important are the coagulase-negative staphylococci by their adherence and growth on surfaces of intravenous catheters. The structural components, the enzymes and toxins are the most important factors that take up the capacity of the agent in developing nosocomial infections. Handwashing practices, antibiotic prophylaxis are important, especially in the immunocompromised host.
Cross Infection↗
Specificity grouping of the accessory gene regulator quorum-sensing system of Staphylococcus epidermidis is linked to infection.
Staphylococcus epidermidis represents the most frequent pathogen involved in nosocomial infections and infections of indwelling medical devices. The strain-to-strain variation of the gene encoding the quorum-sensing pheromone of S. epidermidis as well as the correlation between specificity groups and origin from infection were determined. The pro-pheromone gene was highly conserved and showed infrequent, non-synonymous, single-nucleotide polymorphisms that led to conservative amino acid exchanges only. Importantly, one specificity group was significantly more frequent among strains isolated from infection. The finding that quorum-sensing specificity groups are linked to infection demonstrates the relevance of quorum-sensing for virulence in this critical human pathogen and contributes to the scientific basis needed for the development of quorum-sensing-targeting drugs.
Amino Acid Sequence↗
Clinical and molecular aspects of the pathogenesis of Staphylococcus aureus bone and joint infections.
Staphylococcus aureus is an important cause of bone and joint infections. In recent years, significant changes in the incidence of septic arthritis and osteomyelitis have occurred. Haematogenous osteomyelitis is now less common during childhood, but secondary spread of infection to bone or joint from a contiguous site in adults is increasing in incidence. Infection introduced at the time of surgery or arising by the haematogenous route is a significant complication of prosthetic joint implantation, and the effect of bone cement on local immune function may be important in this setting. ALthough S. epidermis is a more common cause of prosthetic joint infection, S. aureus is more difficult to treat. S. aureus produces a number of extracellular and cell-associated factors, but it is unclear what role these have as virulence factors in vivo. Furthermore, it is difficult in animal models to simulate transient bacteraemia followed by non-fulminating septic arthritis or osteomyelitis, as occurs in the patient. Surface factors which may be important in pathogenesis include the cell wall (activates complement and stimulates cytokine release), capsular polysaccharide (promotes adhesion to host cell surfaces), collagen receptors and fibronectin-binding protein. Staphylococcal toxic shock syndrome toxin (TSST-1) and the enterotoxins are superantigens and have the potential to suppress plasma cell differentiation and antibody responsiveness. TSST-1-positive isolates have been shown to cause more severe joint infection in one animal model, but most other studies to date have focused on in-vitro rather than in-vivo effects. There is little evidence supporting a role for coagulase, lipase and the haemolysins in staphylococcal bone and joint infections. Despite the clinical importance of these infections, surprisingly little is known about pathogenesis at the cellular level. Future research should focus on the role of the host immune system in limiting spread of infection, and the expression of virulence factors in animal or other models incorporating isogenic mutant strains.
Arthritis, Infectious↗
Brucellosis of the spine with a synchronous Staphylococcus aureus pyogenic elbow infection.
Staphylococcus aureus osteomyelitis and pyogenic arthritis has a different pattern in the elderly than in the young. The axial skeleton is the most frequent site of infection and treatment is usually by intravenous antibiotics. We report a case of Staph. aureus septic arthritis of the elbow with concomitant osteomyelitis of the spine that was thought to be due to Staph. aureus, but culture of debrided material from the lesion grew Brucella in culture. We suggest that in the elderly it is advisable to obtain a tissue culture diagnosis and not to instigate therapy based on positive blood cultures or a concomitant infection.
Aged↗
Molecular population and virulence factor analysis of Staphylococcus aureus from bovine intramammary infection.
Staphylococcus aureus isolates from cows in Ireland (n = 102) and the USA (n = 42) were characterized by RAPD-PCR and analysed for the production of a number of putative virulence factors. Of these strains 63 representative isolates were screened for the corresponding virulence factor genes by PCR or Southern hybridization or both. The isolates were divided into 12 distinct clonal types on the basis of their RAPD fingerprint profiles. Of the isolates, 107 (74.3%) tested positive for clumping factor in a slide agglutination test, all 24 RAPD type 7 isolates being negative for clumping factor. PCR analysis of region R, a repeat region of the clfA gene, revealed eight region-R sizes. There was a strong association between RAPD type and the clfA region-R genotype among Irish isolates. Of the RAPD type 7 isolates, 21 (87.5%) coproduced toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin C (SEC). Over 90% of isolates demonstrated haemolytic activity on sheep or rabbit red blood cells and all isolates harboured the gamma-haemolysin (hlg) locus. Of the Irish isolates, all those of RAPD type 7 were sensitive to penicillin G, whereas 86% of RAPD types 4 and 5 strains were resistant. Furthermore, RAPD types 5 and 7 were more likely to be associated with clinical mastitis whereas RAPD type 4 isolates were more often associated with a latent infection. The current study identifies some of the putative virulence factors produced by the predominant clonal types of bovine Staph. aureus that may be considered as components of a vaccine.
Animals↗
The effect of colonization of the mouse mammary gland by Staphylococcus epidermidis on subsequent infection with Staphylococcus aureus or Escherichia coli.
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Animals↗
Occurrence of ica genes for slime synthesis in a collection of Staphylococcus epidermidis strains from orthopedic prosthesis infections.
Staphylococcus epidermidis is a frequent pathogen in infections associated with orthopedic implants. We studied 123 S. epidermidis strains from infections related to orthopedic implants, as regards their ability to express a factor of virulence, namely the slime, an extracellular polysaccharide, which mediates adherence to implants and bacterial colonization. The slime-producing ability was determined by PCR detection of icaA and icaD genes responsible for slime synthesis, and by culture on Congo red agar plates in which slime-producing strains form black colonies, while nonslime-forming ones develop red colonies. 56% of the S. epidermidis isolates were icaA- icaD-positive and grew to become black colonies. In the evaluation of the distribution of slime-forming strains in different sites and types of implants, we found a slight, but not statistically significant, increase in slime-forming strains in total joint prostheses, where tissue compression near the articular faces can form niches in which bacteria crowd, sheltered by the slime. Our findings confirm the role of ica genes as a virulence marker in the pathogenesis of implant-associated orthopedic infections. However, they do not show the existence of a higher frequency of slime-positive strains in a specific type of implant.
Congo Red↗