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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of wound dressings on growth and exotoxin production by staphylococcus aureus

Buck, Rachael January 2003 (has links)
Toxic shock syndrome is a rare complication of Staphylococcus aureus infection associated with small burn wounds of under 5 % total body surface area; it is predominantly observed in young children. Environmental factors that occur within a burn wound have been suggested to increase the risk of TSS developing, and wound dressings have been implicated to contribute to this risk. This study examined the effects of 11 wound dressings on the production of TSST-1 by two strains of S. aureus (strains T1 and T4). Initially, the effects of the wound dressings on growth and exotoxin production were assessed using a liquid culture medium, as this was used in other studies. The results indicated that growth was not markedly affected using this system, however there were a number of problems associated with the evaluation. TSST-l production was altered (increased or decreased) depending upon the dressing type, the gaseous environment or the strain of S. aureus used. Other exotoxins did not appear to be greatly affected by any of the dressings. When a semi-solid system was developed to minimise disintegration of the dressings and simulate a more appropriate wound model in terms of support and environment, similar results were observed as to those found in a liquid culture system. A l-layered semi-solid agarose system incubated in 6 % (v/v) carbon dioxide supported optimum TSST-1 production by both test strains in the presence and absence of most wound dressings. Actisorb Plus™ and crepe increased TSST-l production. Levels of TSST-l increased over time and Actisorb Plus™ continued to stimulate increased toxin production. Gamgee, and Biobrane ™previously implicated. in TSS, increased TSST-1 production t.. . I between 48-72 hours. Serine, thiol and metalloproteases were produced by both strains of S. aureus and proportions of each were altered by the presence of dressings. This study showed that some wound dressings may potentially increase the risk of a patient developing TSS, but further studies need to be done in vivo.
2

Fulminant Puerperal Sepsis caused by Hemolytic Group A Streptococci and Toxic Shock Syndrome – A Case Report and Review of the Literature

Bauerschmitz, G., Hellriegel, M., Strauchmann, J., Schäper, J., Emons, G. 03 September 2014 (has links)
Summary Puerperal sepsis is a rare but serious and potentially lethal syndrome. It is imperative that severe postpartum malaise is taken seriously; early initiation of antibiotic therapy before sepsis becomes manifest can save lives.
3

Regulation of #alpha#-haemolysin gene expression in Staphylococcus aureus

Sullivan, Derek J. January 1990 (has links)
No description available.
4

Genetic analysis of toxic shock syndrome toxin-1 production by Staphylococcus aureus strains

Chu, May Chin-May January 1985 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1985. / Bibliography: leaves 119-128. / Photocopy. / Microfilm. / ix, 128 leaves, bound ill. 29 cm
5

The role of toxic shock syndrome toxin-1 in the pathogenesis of toxic shock syndrome

Rosten, Patricia Melanie January 1986 (has links)
Toxic shock syndrome toxin-1 (TSST-1), an exoprotein produced by some strains of Staphylococcus aureus, is implicated in the pathogenesis of menstrual TSS. However, its role in nonmenstrual TSS is less certain. In order to study the pathogenetic role of TSST-1 in TSS, three approaches were taken: a) to develop an ELISA for detection of TSST-1 in biologic fluids in order to verify TSST-1 production in vivo in TSS patients, b) to quantitate TSST-1 specific antibodies in the serum of TSS patients and controls to determine whether such antibodies are protective, and c) to attempt to identify other staphylococcal products which may be implicated in some forms of TSS. A sensitive and specific noncompetitive enzyme-linked immunosorbent assay (ELISA) capable of detecting TSST-1 at concentrations from 0.5 to 16 ng/ml was developed. This assay did not detect other staphylococcal enterotoxins including A, B, C₁, C₂, C₃, D and E. Possible interference by protein A was readily eliminated by pretreatment of test samples with 10% nonimmune rabbit serum. The assay was adapted for rapid screening of TSST-1 production by S. aureus isolates in culture supernatants in vitro, and for the detection of TSST-1 in vaginal washings and urine of TSS patients and healthy controls in vivo. All 35 S. aureus isolates confirmed to be TSST-1 positive by Ouchterlony immunodiffusion, and 59 of 60 isolates confirmed to be TSST-1 negative, gave concordant results by ELISA. Interestingly, toxigenic S. aureus strains isolated from TSS patients quantitatively produced significantly more toxin in vitro compared to toxigenic control strains (p<0.05, Mann-Whitney rank sum test). TSST-1 could be detected by ELISA in 3 of 4 vaginal washings collected within 3 days of hospitalization from 3 women with acute menstrual TSS, compared to 0 of 17 washings from 9 TSS women collected greater than 3 days after hospitalization (p=0.003, Fisher's exact test) and 1 of 15 washings from 14 healthy control women (p=0.016). TSST-1 was not detected in the urine of 4 acute TSS patients, 2 convalescent TSS patients or in 3 control urine tested. A sensitive and reproducible ELISA was also developed for the quantitation of TSST-1 specific IgG in serum. Anti-TSST-1 was assessed in acute and convalescent sera from 16 nonmenstrual (9 female, 7 male) and 14 menstrual TSS patients, and from 87 healthy women and 66 healthy men as controls. Quantitative levels of anti-TSST-1 in the study groups were calculated as the percent of standard activity (POSA) relative to a medium titre reference serum standard. ELISA titers in acute sera from menstrual TSS (26.2 ± 5.2, mean POSA ± S.E.M.), but not nonmenstrual TSS women (71.8 ± 18.6), were significantly lower than in healthy controls (78.9 ± 7.3) (p<0.01, Mam-Whitney test). Titers from menstrual TSS patients remained low (25.2 ± 10.7) even during late convalescence (mean duration 20 months after illness onset), compared to healthy female controls (p<0.05). Acute titers in males with TSS (37.0 ± 15.6) were also significantly lower than those in control men (114.6 + 11.0) (p<0.05). An inverse relationship of recovery of toxigenic S. aureus and anti-TSST-1 titers in acute sera of TSS patients was observed. Interestingly, antibody titers in control men were significantly higher than in control women (p<0.001). No age-dependent effects or interactive effects of age and sex on ELISA titers were observed. To enable immunoblot analyses, TSST-1 was produced and partially purified using column chromatography techniques. Percent recovery of TSST-1 from culture supernatant through to the final procedure was approximately 15.5%. The relative purity of TSST-1 (TSST-l/total protein, w/w) was increased from 0.21% in culture supernatants to 94.4% in the final product. Ouchterlony immunoprecipitation against reference rabbit antitoxin demonstrated identity with reference TSST-1 as well as with TSST-1 prepared in other laboratories. Physical characterization demonstrated a molecular weight of 24 kd and a pi of 7.0. Using pooled normal human serum as a first antibody probe, several bands in addition to the 24 kd TSST-1 band were visualized by immunoblot against our partially purified toxin as well as similar preparations obtained from other investigators. To determine whether any of the additional bands might be implicated in TSS, acute and convalescent sera from TSS patients were used to probe for immunoreactive bands in our partially purified TSST-1 as well as a commercially obtained preparation. Seroconversion was demonstrated to the 24 kd TSST-1 protein in 7 of 10 TSS patients from whom toxigenic S. aureus was isolated. In addition, seroconversion was noted to a 49 kd band in 4 patients, to a 21 kd band in 3 patients, to a 28 kd band in 1 patient and to a 32 kd band in 2 patients. In conclusion: 1) the ability to measure TSST-1 in biologic fluids lends stronger support for the role of TSST-1 in menstrual TSS patients; 2) the serologic data support the etiologic role of TSST-1 in menstrual TSS and in nonmenstrual TSS patients from whom toxigenic S. aureus could be cultured, but not for nonmenstrual TSS women from whom toxigenic S. aureus was not isolated; 3) immunoblotting results with acute and convalescent sera from TSS and control patients, not only add further support to the role of TSST-1 in patients from whom toxigenic S. aureus could be isolated, but also indicate that there may be several other staphylococcal products implicated in TSS, particularly in whom antibody to TSST-1 pre-existed in acute sera. The nonresponsiveness or lack of seroconversion to TSST-1 in some patients could suggest either: a) TSST-1 was not the etiologic agent for such patients; b) TSST-1 was the etiologic agent, but the exposure was sufficient for an immune response (similar to tetanus), or; c) some immunologic defect may be present. Future studies are required to clarify these possibilities. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate
6

Contralateral compartment syndrome inoculated by invasive group A streptococcus

Chen, Huiwen, Mcphillips, Sean Thomas, Chundi, Vishnu 24 January 2017 (has links)
Compartment syndrome is a rare but a well-documented complication in patients with trauma-induced group A streptococcus infection. Here, we present a case of a male who developed compartment syndrome on the left lower extremity after an injury inoculated by group A streptococcus on the right lower extremity. The patient was resuscitated with antibiotics, urgent fasciotomy, and immunoglobulin. The patient was eventually transferred to a burn center for further care.
7

Caractérisation, épidémiologie et pathogénie d'un clone de Staphylococcus aureus résistant à la méticilline portant le gène de la toxine du choc toxique staphylococcique (TSST-1) / Characterisation, epidemiology and pathogeny of a methicillin-resistant Staphylococcus aureus clone containing the toxic shock syndrome toxin-1 gene (TSST-1)

Durand, Géraldine 17 December 2009 (has links)
La plasticité génomique de Staphylococcus aureus lui permet d’acquérir des gènes codant des facteurs de virulence mais aussi des gènes de résistance aux antibiotiques, notamment la cassette de résistance à la méticilline (SCCmec). La résistance à la méticilline est d’abord apparue dans des souches hospitalières à l’origine de grands clones pandémiques nosocomiaux, puis a ensuite émergé en milieu communautaire chez des souches virulentes possédant la leucocidine de Panton-Valentine. Nous avons observé en 2002, en milieu hospitalier et communautaire, l’émergence inquiétante de S. aureus résistant à la méticilline (SARM) portant le gène tst de la toxine du choc toxique staphylococcique (TSST-1). Notre travail a consisté à : (i) l’élaboration de nouveaux outils contribuant à la description de clones de SARM, notamment d’un outil de typage de la cassette SCCmec, (ii) la caractérisation phénotypique et moléculaire de ce nouveau clone, (iii) l’étude de l’épidémiologie de ce clone, (iv) l’exploration de la pathogénie de ce clone en recherchant les propriétés génétiques qui lui confèrent une telle virulence et épidémicité, et notamment en identifiant le rôle de la TSST-1. Le clone de SARM tst+ est un clone épidémique de fond génétique ST5 en Multi Locus Sequence yping, atteignant principalement les sujets jeunes, et responsable d’infections variées à la fois toxiniques et suppuratives. Il est doté d’une cassette SCCmec atypique de type I tronquée dont le rôle dans le potentiel épidémique et de virulence de ce clone reste à déterminer. Enfin, la TSST-1 ne semble pas jouer un rôle déterminant, direct ou indirect, dans la pathogénie pléiotropique de ce clone / The plasticity of the Staphylococcus aureus genome confers to this specie the ability to gain accessory genes encoding virulence factors as well as antibiotic resistance determinants such as Staphylococcal cassette chromosome mec SCCmec that encodes methicillin-resistance. Methicillin resistance first emerged in hospital-acquired strains originally of successful nosocomial pandemic clones, and is also risen in virulent community-acquired strains containing the Panton-Valentine leucocidin. In 2002, we observed the worrying emergence of a new methicillin-resistant S. aureus (MRSA) clone that contains the tst gene encoding toxic shock syndrome toxin (TSST-1) responsible for both hospital and community-acquired infections. Our study was focused on: (i) new tools for MRSA description, mainly on a SCCmec typing tool, (ii) the characterisation of this new clone by molecular and phenotypic methods, (iii) the epidemiology of this clone, (iv) the pathogenic potential of this clone and the investigation of the genetic features that enhance transmission and virulence, particularly the role of TSST-1. The tst+ MRSA clone is an epidemic clone of genetic background ST5 by multilocus sequence typing that occurs mainly in young people and is responsible for a wide diversity of clinical syndromes including toxin-mediated and suppurative diseases. This clone harbours a peculiar cassette “truncated SCCmec type I” which could play an important role in virulence and transmission but are still under investigation. TSST-1 does not play a determining role (either directly or indirectly) in the pleiotropic pathogenesis of this clone

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