Zentralblatt fur Bakteriologie. 1. Abt. Originale. A: Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie最新文献

Sensitivity determinations with 6 strains of Clostridium histolyticum showed that the inhibitory action of metronidazole was highly dependent on the oxygen concentration of the environment. Under anaerobic conditions they were sensitive but at increased oxygen concentrations moderately sensitive or resistant. The flexible resistance of this aerotolerant anaerobe against metronidazole may interfere with results of sensitivity determinations, estimation of blood levels and it may influence the effectiveness of the drug in anaerobic infections due to aerotolerant anaerobes.

T-proteins of Streptococcus pyogenes type 1 were extracted by enzymatic treatment of cells with trypsin, pepsin or C-phage-associated lysin and subsequently purified by ion exchange chromatography on DEAE cellulose as well as by immuno-adsorption on immobilized anti-T-type 1 antibodies. Immunochromatographical purified T1-proteins which were extracted by the different enzymes showed different properties in immuno-electrophoresis, SDS-electrophoresis and amino acid composition although a serological reaction of identity was found in Ouchterlony precipitation. Tryptic and peptic digestion was efficient for extraction of T protein while the extraction with C-phage-associated lysin was unsuitable for isolation of T-protein. The release of T-protein after treatment of cells with this lysin was very low and the preparation purified by this way exhibited cross-reaction with non-absorbed antisera of other types.

Out of the 2,527 strains typed in 1976, 1977, 1978 and 1979, 226 strains (8.94%) were lysed by phages 94, 96 or 94 + 96. The two phages lyse together 83.17% of strains, whilst phage 94 alone lyses only 3.96% and phage 96 alone 12.87%. 94/96 strains have the S. aureus species antigens, particularly that of biotype A (human) at levels similar to those previously described: Protein A 96%, beta Ribitol teichoic acid (93%). Very characteristic is the presence in these strains of type antigens c1 (89%) and sigma (92%), which are significantly unusual or absent in the strains of other phages types. 94-96 complex strains are sensitive to antibiotics except resistance to Penicillin G (95%), Tetracycline (48%), Doxycycline (25%). Relation between lysis by phages 94-96 and presence of antigens c1 and sigma is discussed.

Phagocytosis of Klebsiella pneumoniae by alveolar macrophages of guinea pigs was investigated. Lavage of guinea pig lungs yielded a cell suspension of approximately 85% alveolar macrophages. The remaining cells were predominantly lymphocytes and a few polymorphonuclear leucocytes. After incubation for 5 hours at 37 degrees C the macrophages adhered to the glass surface whereas leucocytes could be washed away. This resulted in a pure culture of macrophages containing 95-98% living cells. Specific antibodies to phenol-water extracts of K. pneumoniae were induced in rabbits. These antisera increased the rate of uptake of the bacteria by macrophages at least 35-fold as compared to macrophages without added antiserum. Preimmunization sera of rabbits also increased the uptake of bacteria by macrophages but by far less than hyperimmune sera. A very sensitive Enzyme-Immuno-Assay (ELISA) for detection of antibodies to the phenol-water extracts of K. pneumoniae was developed. Low levels of antibodies were demonstrated in the pre-immunization sera of rabbits by ELISA but not by the tube agglutination test. These low antibody titers could explain the increased uptake of the bacteria by alveolar macrophages in the presence of preimmunization sera. The influence of complement components on phagocytosis in our sera was small and was therefore not studied in any detail.

The effect of gentamicin and cephalothin on the phagocytosis of Klebsiella pneumoniae by alveolar macrophages of guinea pigs was tested. At their minimal bactericidal concentration (MBC) the antibiotics did not influence the uptake of bacteria by macrophages in the presence of various antibody titers. As expected, the number of surviving bacteria after intracellular ingestion decreased at MBC of the antibiotics. The uptake of bacteria was inhibited by very high concentrations of gentamicin and cephalothin only. The intracellular killing of the bacteria was already higher in the presence of relatively low antibiotic concentrations (one third of the minimal inhibitory concentration, MIC) as compared to the killing without antibiotics. Above this levels, even if they were considerably higher than the MIC, the antibiotics had no additional effect on the number of bacteria surviving after ingestion. These findings indicate that concentrations above one third of the MIC of gentamicin or cephalothin are not necessarily of advantage for the effect of macrophages on the bacteria, provided that sufficient levels of antibodies are also present.

By means of bacteriocin typing epidemic studies were carried out with regard to 65 strains of Enterobacter cloacae, isolated from various specimens of 59 patients. Based on detailed preliminary investigations the presentation with bacteriocins in liquid cultures induced by Mitomycin C was found most preferable. Since constant and reproducible results are essential, standardization of culture media, incubation temperature, incubation time and inoculum size is required. By means of 13 bacteriocin-producing strains the isolates could be typed and categorized into 24 types according to their sensitivity to bacteriocins. A rather varied picture emanated from the distribution of the individual types with regard to the different medical fields so that cross-infection with a certain strain was negligible. Seeing that one bacteriocin type was found predominantly in the intensive care unit, it can be maintained that this strain originated from the ward itself. The importance of bacteriocin typing for the interpretation of certain up-to-date epidemic situations is obvious which typing has also been successfully employed with regard to investigations of Enterobacter cloacae infections. However, it is doubtful whether bacteriocin production and bacteriocin sensitivity sufficiently constant in order to obtain comparable results over a more extended period of time and in different areas.

Two proteolytic enzymes of Pseudomonas aeruginosa--an alkaline protease and an elastase--were incubated with human myeloma proteins IgG and IgA as well as with secretory IgA at 37 degrees C. Digest mixtures were analyzed after 1, 5, 12, 24, 48 and 72 h by SDS-polyacrylamide gel electrophoresis after reduction by 2-mercaptoethanol. Under conditions which resulted in cleavage of all three immunoglobulins by the elastase in the hinge-region, the alkaline protease cleaved only IgA. It was suggested that proteases of PA interfere with the immune-system of the host by cleavage of immunoglobulins. Elastase-positive PA strains should be more virulent compared with PA strains which produce only alkaline protease or are protease-negative at all.

The isolation and analysis of the Citrobacter O-serogroup Ci23Vi+ murein are described. The murein consists of alanine, glutamic acid, diaminopimelic acid (occurring in the molar ratio 1.5 : 1: 0.9), N-acetylmuramic acid and N-acetylglucosamine. Dialysable products resulting from the digestion of the Citrobacter O-serogroup Ci23Vi+ murein with egg white lysozyme resemble closely those obtained from the E. coli B murein.

Alkaline protease (protease I) and a protease with elastase activity (protease II) were isolated from two different strains of Pseudomonas aeruginosa (PA). Proteolytic activity was measured during the early exponential phase of growth and was highest when cultures reached the stationary growth phase. The extracellular character of protease I and II was demonstrated by measuring the intra- and extracellular ATP-concentration. Purification was achieved by precipitation with 65% ammonium sulfate, precipitation with 70% acetone, gelfiltration on Sephadex G-100 and chromatography on DEAE-Sephacel. The purified proteases were characterized. The pH for optimal proteolytic activity of protease I was at pH 9--10, for protease II at pH 8--9. Both enzymes cleaved casein and gelatine, in addition protein II elastin. Enzymatic activity of protease II was inhibited by 10(-3) M EDTA at pH 8.1 to 82%. Inactivation of protease I was not achieved by 10(-2) M EDTA. Molecular weight of protease I was estimated at 57,000, molecular weight of protease II at 39,000. Both enzymes consist of one polypeptide chain. In isoelectric focusing the protease I was separated into two components with pH values of 8.5 and 8.7, while protease II had isoelectric points of pH 6.0 and 6.4. Further characterization of protease I was done with amino acid analysis. Protease I was fairly stable over a pH range of 6--9 at room temperature. The optimal temperature for proteolytic activity was 60 degrees C. The results are discussed in view of proteases of other PA-strains.