Biomedical subjects
Publications and source records attributed to F Schumacher-Perdreau.
A 1.3-kb DNA fragment isolated from Staphylococcus haemolyticus strain DSM 20264 can be used as a specific probe for this species. The probe hybridized with 39 clinical isolates of S. haemolyticus but not with any of the 121 isolates representative of the other 25 species of staphylococci described to date.
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The contribution of the cytokine tumor necrosis factor (cachectin; TNF) to host defenses against staphylococcal foreign body infections was studied in vivo. In tissue cages subcutaneously implanted into guinea pigs, progressive infection was initiated by a very low inoculum (100 cfu) of Staphylococcus aureus with a success rate of 100%, as is frequently encountered in related clinical situations. Locally injected autologous bacterial components derived from the cell wall of S. aureus, in particular peptidoglycan, were very active in raising TNF levels in tissue cage fluid and in preventing the development of infection by the 100% infective dose of the test strain. Furthermore, injection of murine recombinant TNF into tissue cages could substitute for the bacterial components in preventing experimental infection by S. aureus. The protective effect of TNF-eliciting bacterial components could be neutralized by anti-TNF antibodies. A local increase in TNF levels might improve host defenses against staphylococcal foreign body infections.
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The survival of Staphylococcus epidermidis strain KH 11 in the presence of synthetic high molecular polyurethanes was prolonged in comparison to control experiments performed in the absence of any nutrients. Investigations of the bacteria after contact with the polymers revealed changes in their surface properties and metabolism, in particular a marked induction of urease activity. ESCA (Electron Spectroscopy for Chemical Analysis) measurements detected a decrease in elementary nitrogen in the polyurethane surfaces after incubation with the bacteria. The alterations observed indicate an urease-induced degradation of synthetic polymers by Staphylococcus epidermidis KH 11.
A case of severe endophthalmitis after cataract extraction followed by posterior chamber lens implantation is reported. Microbiological cultures from a tap of the patient's aqueous humour prior to lens explantation as well as from the explanted lens and aqueous and vitreous humour during operation yielded Staphylococcus epidermidis sensu stricto. Scanning electron microscopy showed massive colonisation of the lens loop by staphylococci. Clonal identity of all isolates was demonstrated by plasmid DNA analysis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of extra-cellular products. This is strongly suggestive of the aetiological role of S. epidermidis in this case of late onset endophthalmitis.
Polymer-associated infection is a problem of increasing importance in modern medicine. In a new approach to prevent such infections we have modified polyvinylfluoride (TEDLAR) films by graft copolymerization with N-vinylpyrrolidone to which iodine can be complexed. Grafting reaction was performed by the preirradiation technique using an electron accelerator. Grafted films were then treated in Lugol's solution for at least 24 h. Release of free iodine from the films was determined either by titration or using the agar disc diffusion test, showing an iodine release for up to 4-5 days. The antimicrobial activity of the films was tested in bacterial adhesion measurements. Bacterial and fungal cells in the range of 10(3) to 10(6) cfu/cm2 polymer were found on control samples without iodine, whereas on iodine-complexed films no viable cells could be detected at least for 5 days or even longer. Thus, microbial adhesion and growth can be inhibited by iodine-containing polymers.
An encapsulated strain of Staphylococcus simulans was observed to be more resistant to phagocytosis by human granulocytes than was a nonencapsulated strain. Phagocytosis of the encapsulated strain was enhanced by antisera to S. simulans, but opsonic activity of antisera was removed by absorption with S. simulans capsular material. The encapsulated strain of S. simulans was also more invasive than the nonencapsulated S. simulans in vivo. More encapsulated than nonencapsulated S. simulans were found in heart blood when equal numbers of organisms were injected intraperitoneally into mice. Invasion of the bloodstreams of mice by encapsulated S. simulans was prevented by passive immunization (rabbit antiserum). Thus, the capsule of S. simulans inhibited phagocytosis in vitro and contributed to virulence in vivo.
The significance of polymer-associated infections caused by coagulase-negative staphylococci is discussed. The aspects of bacterial adhesion to polymeric materials as the first important pathogenetic step in the development of such infections are treated. The role of extracellular slime substance (ESS) produced by the bacteria in the pathogenesis is elucidated and newer results concerning the interference of ESS with host defense mechanisms and antibiotic therapy are presented. As an approach to the prevention of polymer-associated foreign-body infections, the modification of the polymeric materials is introduced. Results of recent studies to achieve antiadhesive materials by radiation modification of polymers as well as the development of antimicrobial surfaces by incorporating or bonding antibiotics to polymers are presented.
Recent data suggest that fibronectin may favor Staphylococcus aureus infection by promoting attachment to either injured tissues or implanted foreign bodies. Using a previously described in vitro assay, we show that promotion of S. aureus adherence by surface-bound fibronectin, adsorbed on polymethylmethacrylate (PMMA) coverslips, is antagonized by antistaphylococcal antibodies present in immunoglobulin G (IgG) purified from human plasma. Among the different organisms tested, the protein A-deficient strain Wood 46 of S. aureus was the most strongly inhibited by purified IgG or whole serum dose-dependently. Bacterial adherence was not influenced by preincubating fibronectin-coated PMMA with either purified IgG or whole serum. However, inhibition of bacterial adherence was directly related to the extent of IgG binding to S. aureus Wood 46. When F(ab')2 fragments of purified IgG were tested in the adherence assay, they could also reduce the interaction between S. aureus Wood 46 and fibronectin-coated PMMA. Two other staphylococcal strains were also tested in the adherence inhibition assay: Whereas the protein A-rich strain Cowan I of S. aureus was moderately inhibited by purified IgG or whole serum, S. epidermidis KH 11 was not at all inhibited by IgG which bound poorly to the bacterial cells. This study has demonstrated that bacterial coating by humoral factors, and specifically IgG, may influence significantly subsequent adherence of S. aureus to surface-bound fibronectin.
The polyvalent staphylococcal bacteriophage U16 failed to adsorb to an encapsulated Staphylococcus simulans strain. Partially purified cell wall and teichoic acid of this strain could, however, inactivate bacteriophage U16 to a great extent, indicating the presence of the phage receptor. It is concluded that the capsule of Staphylococcus simulans acts as a barrier for the interaction of the phage with its receptor in the bacterial cell wall.
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On 14 encapsulated Klebsiella strains with different K-antigens and their non-encapsulated mutants the type of fimbriae present and the grade of hydrophobicity of their cell surface (expressed as SAT-value) were investigated. It could be demonstrated that clear correlations exist between the fimbriation of Klebsiella bacteria and their cell surface hydrophobicity. On the other hand, the presence of capsules and the type of K-antigen showed no influence on the degree of hydrophobicity.
A simple phage adsorption test is recommended for differentiation between staphylococci and micrococci. All 132 strains of Staphylococcus tested inactivated phage U16 significantly, whereas of 123 strains of Micrococcus tested, only three strains of Micrococcus candicans were able to adsorb this staphylococcal phage. There are special problems in the taxonomy of M. candicans.
The coagulase-negative staphylococcal species S. xylosus and S. saprophyticus are able to inactivate phages of the International Basic Set for S. aureus. The cell wall teichoic acids of these species contained two polyols: glycerol and ribitol. Removal of ribitol teichoic acid resulted in a parallel decrease in the ability of the cell walls to inactivate the phages.
The cell wall composition, the configuration of lactic acid produced from glucose under anaerobic conditions, the occurrence of fructose-1,6-diphosphate (FDP) activated L-lactate dehydrogenase (L-LDH), and the esterase pattern were determined from more than 80 strains of coagulase-positive staphylococci isolated from man and animal. Strains isolated from man, swine, bovines and hares form a rather homogeneous group. They exhibit a similar cell wall composition, produce predominantly D,L-lactate and have a characteristic and simple esterase pattern. Coagulase-positive staphylococci isolated from dogs, horses, minks and pigeons are quite distinct from typical Staphylococcus aureus strains. They exhibit a different cell wall composition, produce only L-lactate, possess an L-LDH which is specifically activated by FDP, and have a quite complex esterase pattern.