@article{WirbelauerHofHacker1988, author = {Wirbelauer, J. and Hof, H. and Hacker, J{\"o}rg}, title = {Die Wirkung von Desacetylcefotaxin, einem Metaboliten von Cefotaxim, in vitro und auf die experimentelle Infektion mit Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40348}, year = {1988}, abstract = {Die MHK-Werte von Desacetylcefotaxim gegen verschiedene, z. T. ampicillinresistente St{\"a}mme von Escherichia coH, die mit Hilfe einer Agardilutionsmethode erhoben wurden, waren h{\"o}her als die von Cefotaxim und Ceftriaxon, jedoch niedriger als die von Cefoxitin. In einem Modell der systemischen Infektion der Maus mit einem plasmidtragenden, betalactamaseproduzierenden Stamm von E. coli f{\"u}hrte die Therapie mit Desacetylcefotaxim zu einer starken Reduktion der Keime pro Leber. Im Vergleich zur Therapie mit Cefotaxim trat die protektive Wirkung aber verlangsamt ein. Desacetylcefotaxim ist also kein unn{\"u}tzes Abbauprodukt von Cefotaxim.}, language = {de} } @article{VanDieKramerHackeretal.1991, author = {Van Die, I. and Kramer, C. and Hacker, J{\"o}rg and Bergmans, H. and Jongen, W. and Hoekstra, W.}, title = {Nucleotide sequence of the genes coding for minor fimbrial subunits of the F1C fimbriae of Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40353}, year = {1991}, abstract = {F 1 C fimbriae allow uropathogenic Escherichia coli to adhere to specific epithelial surfaces. This adhesive property is probably due to the presence of minor fimbrial components in F1C fimbriae. The foe gene cluster encoding F1C fimbriae has been cloned, as described previously. Here we present the nucleotide sequence (2081 bp) coding for the F 1 C minor fimbria I subunits. The structural genes code for polypeptides of 175 (FocF), 166 (FocG), and 300 (FocH) amino acids. The deduced amino acids of the F 1 C minor subunits were compared with the reported sequences of the minor subunits of other types of fimbriae. The data show that the Foc minor subunits are highly homologous to the corresponding Sfa proteins, whereas homology to the minor subunits of type 1 and P fimbriae is much lower.}, language = {en} } @article{LueckBenderOttetal.1991, author = {L{\"u}ck, P. Christian and Bender, Larisa and Ott, Manfred and Helbig, J{\"u}rgen H. and Hacker, J{\"o}rg}, title = {Analysis of Legionella pneumophila serogroup 6 strains isolated from a hospital warm water supply over a three-year period by using genomic long-range mapping techniques and monoclonal antibodies}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40392}, year = {1991}, abstract = {Over a period of 3 years, Legionella pneumophila serogroup 6 strains were isolated from warm water outlets and dental units in the Dental Faculty and from the Surgery and Internal Medicine Clinics at the University of Dresden, Dresden, Germany. In the bacteriological unit of the above-mentioned facility, L. pneumophila serogroups 3 and 12 were grown frl,)m warm water specimens. The medical facilities are located in separate buildings connected with a ring pipe warm water system. All L. pneumophila serogroup 6 strains isolated from the warm water supply reacted with a serogroup-specific monoclonal antibody, but not with two other monoclonal antibodies which are subgroup specific, reacting with other serogroup 6 strains. The NolI genomic profiles obtained by pulsed-field gel electrophoresis of 25 serogroup 6 strains isolated from the Dental Faculty over a 3-year period, 1 isolate from the Internal Medicine Clinic, and 4 strains from the Surgery Clinic were identical. Furthermore, all these strains hybridized with a 3OO-kb NolI fragment when a legiolysin (lIy)-specific DNA probe was used. The NolI pattern, however, differed from those of six serogroup 6 strains of other origins, one serogroup 12 strain from the bacteriological unit, and another six unrelated strains of serogroups other than serogroup 6. L. pneumophila serogroup 6 strains which can be divided into only two subgroups by the use of monoclonal antibodies are differentiated in at least six Noli cleavage types obtained by pulsed-field electrophoresis.}, language = {en} } @article{KuninHuaVanArsdaleWhiteetal.1993, author = {Kunin, Calvin M. and Hua, Tong Hua and Van Arsdale-White, Laura and Krishnan, Chandradekar and Hacker, J{\"o}rg}, title = {Isolation of a nicotinamide-requiring clone of Escherichia coli O18:K1:H7 from women with acute cystitis resembles strains found in neonatal meningitis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40406}, year = {1993}, abstract = {During a study of the nutritional requirements of clinical isolates of Escherichia coli, we found that 21 (7.0\%) of 301 strains required nicotinamide to grow in minimal medium. The nicotinamide- requiring strains were present in 16 (15.8\%) of 101 cultures of urine from young women with acute cystitis, in 5 (5.0\%) of 100 stool specimens from healthy adults, and in none of 100 blood samples from adult patients with bacteremia. Most of the strains belonged to serogroup OI8:KI:H7, were hemolytic, possessed type I fimbriae, and exhibited similar patterns of antibiotic susceptibility. Two of the urinary isolates expressed S fimbriae, and all 16 urinary isolates contained the s/aS homologue gene on their chromosomes. One of the stool isolates contained the s/aS gene. The urinary isolates closely resembled a large clone of E. coli that is reportedly associated with neonatal meningitis and sepsis. It may be possible to detect this and related clones by their requirement for nicotinamide and to screen strains for S fimbriae by relatively inexpensive hemagglutination methods, including the use of avian PI antigens to detect mannose- resistant, non-P-fimbriated E. coli; the agglutination of bovine erythrocytes; and the use of bovine mucin to detect sialyl galactosides in S fimbriae.}, language = {en} } @article{HackerOttWintermeyeretal.1993, author = {Hacker, J{\"o}rg and Ott, Manfred and Wintermeyer, Eva and Ludwig, Birgit and Fischer, Gunter}, title = {Analysis of virulence factors of Legionella pneumophila.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70620}, year = {1993}, abstract = {Legionella pneumophila, the causative agent of Legionnaires' disease is a facultative intracellular bacterium, which in the course of human infection multiplies in lung macrophages predominantly manifesting as pneumonia. The natural habitat of Legionella is found in sweet water reservoirs and man-made water systems. Virulent L. pneumophila spontaneously convert to an avirulent status at a high frequency. Genetic approaches have led to the identification of various L. pneumophila genes. The mip (macrophage infectivity potentiator) determinant remains at present the sole established virulence factor. The Mip protein exhibits activity of a peptidyl prolyl cis trans isomerase (PPiase), an enzyme which is able to bind the immunosuppressant FK506 and is involved in protein folding. The recently cloned major outer membrane protein (MOMP) could play a role in the uptake of legionellae by macrophages. Cellular models are useful in studying the intracellular replication of legionellae in eukaryotic cells. Human celllines and protozoan models are appropriate for this purpose. By using U 937 macrophage-like cells and Acanthamoeba castellanii as hosts, we could discriminate virulent and avirulent L. pneumophila variants since only the virulent strain was capable of intracellular growth at 37 oc. By using these systems we further demonstrated that a hemolytic factor cloned and characterized in our laboratory, legiolysin (lly), had no influence on the intracellular growth of L. pneumophila.}, subject = {Legionella pneumophila}, language = {en} } @article{TschaepeBenderOttetal.1992, author = {Tsch{\"a}pe, Helmut and Bender, Larisa and Ott, Manfred and Wittig, Walter and Hacker, J{\"o}rg}, title = {Restriction fragments length polymorphism and virulence pattern of the veterinary pathogen Escherichia coli O139:K82:H1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86131}, year = {1992}, abstract = {Escherichia coli 0139: K82: H1 strains originating from outbreaks and single cases of oedema disease in pigs were characterized by their genomic restriction fragment length polymorphism (RFLP), their virulence pattern, and by the occurrence as well as the genomic distribution of the determinants for hemolysin (hly) and verotoxins (shiga-like toxins; sltI, sltII). Whereas the RFLPs revealed considerable variation among the E. coli 0139: K82: H1 isolates depending the origin and epidemic source of the strains, the virulence gene slt II was found to be present in nearly all strains in a particular chromosomal region. Similar to RFLPs, the plasmid profiles are useful for epidemiological analysis.}, subject = {Escherichia coli}, language = {en} } @article{MorschhaeuserVetterKorhonenetal.1993, author = {Morschh{\"a}user, Joachim and Vetter, Viktoria and Korhonen, Timo and Uhlin, Bernt Eric and Hacker, J{\"o}rg}, title = {Regulation and binding properties of S fimbriae cloned from E. coli strains causing urinary tract infection and meningitis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86140}, year = {1993}, abstract = {S fimbriae are able to recognize receptor molecules containing sialic acid and are produced by pathogenic E. coli strains causing urinary tract infection and menigitis. In order to characterize the corresponding genetic determinant, termed S fimbrial adhesin ( sfa) gene duster, we have cloned the S-specific genes from a urinary pathogen and from a meningitis isolate. Nine genes are involved in the production of S fimbriae, two of these, sfaB and sfaC code for regulatory proteins being necessary for the expression of S fimbriae. Two promoters, PB and Pc, are located in front of these genes. Transcription of the sfa determinant is influenced by activation of the promotersvia SfaB and SfaC, the action of the H-NS protein and an RNaseE-specific mRNA processing. In addition, a third promoter, P A• located in front of the major subunit gene sfaA, can be activated under special circumstances. Four genes of the sfa determinant code for the subunit-specific proteins, SfaA (16 kda), SfaG (17 kda), SfaS (14 kda) and SfaH (29 kda). It was demonstrated that the protein SfaA is the major subunit protein while SfaS is identical to the sialic-acid-specific adhesin of S fimbriae. The introduction of specific mutations into sfaS revealed that a region of six amino acids of the adhesin which includes two lysine and one arginine residues is involved in the receptor specific interaction of S fimbriae. Additionally, it has been shown that SfaS is necessary for the induction of fimbriation while SfaH plays a role in the stringency of binding of S fimbriae to erythrocytes.}, subject = {Escherichia coli}, language = {en} } @article{SchrotenWolskePlogmannetal.1991, author = {Schroten, Horst and Wolske, Anja and Plogmann, Ricarda and Hanisch, Franz-Georg and Hacker, J{\"o}rg and Uhlenbr{\"u}ck, Gerhard and Wahn, Volker}, title = {Binding of cloned S-fimbriated E. coli to human buccal epithelial cells-different inhibition of binding by neonatal saliva and adult saliva.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86291}, year = {1991}, abstract = {Investigations were carried out on the adhesion of cloned S-fimbriated E. coli, labelled with fluoresceinisothiocyanate (FITC) to human buccal epithelial cells. Fluorescence microscopic analysis revealed binding of bacteria to 75-95\% of epithelial cells. Inhibition experiments with fetuin, a 1-acid glycoprotein and N-acetyl neuraminic acid confirmed the specificity of bacterial binding to sialoglycoproteins. Further studies using saliva as an inhibitor resulted in a 4-5 times stronger binding inhibition by newborn saliva in comparison to adult saliva coinciding with a 4-5 times higher content of total N-acetyl neuraminic acid in samples of newborn saliva. In Western blot analysis sialoglycoprotein bands with a molecular weight >200 kD reacting with wheat germ agglutinin (WGA), were only identified in samples of newborn saliva. These bands are classified as mucins on account of molecular weight and staining. These data suggest that saliva mucins could represent a major defense mechanism against bacterial infections at a stage of ontogeny where the secretory IgAsystem is not yet developed.}, subject = {Escherichia coli}, language = {en} } @article{ParkkinenHackerKorhonen1991, author = {Parkkinen, Jaakko and Hacker, J{\"o}rg and Korhonen, Timo K.}, title = {Enhancement of tissue plasminogen activator-catalyzed plasminogen activation by Escherichia coli S fimbriae associated with neonatal septicaemia and meningitis.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71566}, year = {1991}, abstract = {The effect of Escherichia coli strains isolated from blood and cerebrospinal fluid of septic infants on plasminogen activation was studied. These strains typically carry a filamentous surface protein, S fimbria, that has formerly been shown to bind to endothelial cells and interact with plasminogen. The bacteria effectively promoted plasminogen activation by tissue plasminogen activator (t-PA) which was inhibited by e-aminocaproic acid. A recombinant strain expressing S fimbriae accelerated t-PAcatalyzed plasminogen activation to a similar extent as did the wild-type strains whereas the nonfimbriate recipient strain had no effect. After incubation with t-PA and plasminogen, the S-fimbriate strain displayed bacterium-bound plasmin activity whereas the nonfimbriate strain did not. Bacterium-associated plasmin generation was also observed with a strain expressing mutagenized S fimbriae that Iack the cell-binding subunit SfaS but not with a strain lacking the major subunit SfaA. Both t-PA and plasminogen bound to purified S fimbriae in a lysine-dependent manner and purified S fimbriae accelerated t-PA-catalyzed plasminogen activation. The results indicate that E. coli S fimbriae form a complex with t-PA and plasminogen which enhances the rate of plasminogen activation and generates bacterium-bound plasmin. This may promote bacterial invasion and persistence in tissues and contribute to the systemic activation of fibrinolysis in septicaemia.}, subject = {Escherichia coli}, language = {en} } @article{HackerOttBlumetal.1992, author = {Hacker, J{\"o}rg and Ott, Manfred and Blum, Gabriele and Marre, Reinhard and Heesemann, J{\"u}rgen and Tsch{\"a}pe, Helmut and Goebel, Werner}, title = {Genetics of Escherichia coli uropathogenicity: Analysis of the O6:K15:H31 isolate 536}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71578}, year = {1992}, abstract = {E. coli strain 536 (06: K15: H31) isolated from a case of acute pyelonephritis, expresses S-fimbrial adhesins, P-related fimbriae, common type I fimbriae, and hemolysins. The respective chromosomally encoded determinants were cloned by constructing a genomic library of this strain. Furthermore, the strain produces the iron uptake substance, enterocheline, damages HeLa cells, and behaves in a serum-resistant mode. Genetic analysis of spontaneously arising non-hemolytic variants revealed that some of the virulence genes were physically linked to large unstable DNA regions, termed "pathogenicity islands", which were mapped in the respective positions on the E. coli K-12linkage map. By comparing the wild type strain and mutants in in vitro and in vivo assays, virulence features have been evaluated. In addition, a regulatory cross talk between adhesin determinants was found for the wild-type isolate. This particular mode of virulence regulation is missing in the mutant strain.}, subject = {Escherichia coli}, language = {en} }