TY - JOUR A1 - Schneider, György A1 - Dobrindt, Ulrich A1 - Middendorf, Barbara A1 - Hochhut, Bianca A1 - Szijártó, Valeria A1 - Emódy, Levente A1 - Hacker, Jörg T1 - Mobilisation and remobilisation of a large archetypal pathogenicity island of uropathogenic \(Escherichia\) \(coli\) \(in\) \(vitro\) support the role of conjugation for horizontal transfer of genomic islands JF - BMC Microbiology N2 - Background: A substantial amount of data has been accumulated supporting the important role of genomic islands (GEIs) - including pathogenicity islands (PAIs) - in bacterial genome plasticity and the evolution of bacterial pathogens. Their instability and the high level sequence similarity of different (partial) islands suggest an exchange of PAIs between strains of the same or even different bacterial species by horizontal gene transfer (HGT). Transfer events of archetypal large genomic islands of enterobacteria which often lack genes required for mobilisation or transfer have been rarely investigated so far. Results: To study mobilisation of such large genomic regions in prototypic uropathogenic E. coli (UPEC) strain 536, PAI II(536) was supplemented with the mob(RP4) region, an origin of replication (oriV(R6K)), an origin of transfer (oriT(RP4)) and a chloramphenicol resistance selection marker. In the presence of helper plasmid RP4, conjugative transfer of the 107-kb PAI II(536) construct occured from strain 536 into an E. coli K-12 recipient. In transconjugants, PAI II(536) existed either as a cytoplasmic circular intermediate (CI) or integrated site-specifically into the recipient's chromosome at the leuX tRNA gene. This locus is the chromosomal integration site of PAI II(536) in UPEC strain 536. From the E. coli K-12 recipient, the chromosomal PAI II(536) construct as well as the CIs could be successfully remobilised and inserted into leuX in a PAI II(536) deletion mutant of E. coli 536. Conclusions: Our results corroborate that mobilisation and conjugal transfer may contribute to evolution of bacterial pathogens through horizontal transfer of large chromosomal regions such as PAIs. Stabilisation of these mobile genetic elements in the bacterial chromosome result from selective loss of mobilisation and transfer functions of genomic islands. KW - Recombination directionality factor KW - Staphylococcus-aureus KW - Yersinia-pseudotuberculosis KW - Pseudomonas-aeruginosa KW - Bacterial conjugation KW - Suicide vector KW - Gene-transfer KW - Excision KW - Family KW - Evolution Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140975 VL - 11 ER - TY - JOUR A1 - Hacker, Jörg A1 - Kestler, H. A1 - Hoschützky, H. A1 - Jann, K. A1 - Lottspeich, F. A1 - Korhonen, T. K. T1 - Cloning and characterization of the S fimbrial adhesin (SfaII) complex of an Escherichia coli O18:K1 meningitis isolate N2 - S fimbrial adbesins (Sfa), which are able to recognize sialic acid-containing receptors on eukaryotic cells, are produced by Escherichia coli strains causing urinary tract infections or newbom meningitis. We recently described tbe cloning and molecular cbaracterization of a determinant, termed sftJI, from the chromosome of an E. coli urinary tract infection strain. Herewe present data conceming a S fimbria-specific gene duster, designated sfall, of an E. coli newbom meningitis strain. Like tbe Sfal complex, Sfall consists of tbe major subunit protein SfaA (16 kDa) and the minor subunit proteins SfaG (17 kDa), SfaS (15 kDa), and SfaH (29 kDa). The genes encoding tbe subunit proteins of Sfall were identified and sequenced. Their protein sequences were calculated from the DNA sequences and compared with tbose of the Sfal complex subunits. Altbough the sequences ofthe two major SfaA subunits ditf'ered markedly, tbe sequences ofthe minor subunits sbowed only a few amino acid exchanges (SfaG, SfaH) or were completely identical (SfaS). The introduction of a site-specific mutation into the gene sfaSII and subsequent analysis of an SfaS-negative clone indicated that sfaSII codes for the sialic acid-specific adhesin of tbe meninigitis isolate. These data were confirmed by tbe isolation and characterization of tbe SfaSII protein and the determination of its N-terminal amino acid sequence. The identity between the sialic acid-specific adhesins of Sfal and Sfall revealed that difl'erences between the two Sfa complexes with respect to tbeir capacities to agglutinate erythrocytes must result from sequence alterations of subunit proteins other tban SfaS. KW - Infektionsbiologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59853 ER - TY - JOUR A1 - Zingler, G. A1 - Blum, G. A1 - Falkenhagen, U. A1 - Orskov, I. A1 - Orskov, F. A1 - Hacker, Jörg A1 - Ott, M T1 - Clonal differentiation of uropathogenic E. coli isolates of serotype O6:K5 by fimbrial antigen typing and DNA long-range mapping techniques N2 - Escherichia coli isolates of serotype 06: K5 are the most common causative agents of cystitis and pyelonephritis in adults. To answer the question, as to whether strains of this particular serotype represent one special clonal group, out of a collection of 34 serotype 06: K5 isolates [Zingler et al. ( 1990) Zentralbl. Bakteriol Mikrobiol Hyg [A] 274:372-381] 15 strains were selected andanalyzed in detail. The flagellar (H) antigen and the outer membrane protein (OMP) pattern were determined. Furtherserum resistance properties and the genetic presence and expression of other virulence factors, including hemolysin, aerobactin, P fimbriae, S/F1C fimbriae and type 1 fimbriae was evaluated. In~laddition the Xbalmacrorestriction pattern of ten representative isolates was elaborated and the fimbrial (F) antigentype ofthe P fimbriae was determined, to obtain the complete 0: K: H: F pattern. These analyses could clearly show that the 06: K5 isolates do not represent one clonal group. The Xbal-macrorestriction profiles were heterogeneaus and marked differences in the hybridization patterns, using virulenceassociated gene probes in Southern hybridization of long-range-separated genomic DNA, were observed among the strains. However, some of strains showed similarities in the genomic profiles, arguing for clonal groupings among the 06: K5 isolates. lnterstingly the strains grouped tagether exhibited the same fimbrial F typethat many indicate a coincidence of this phenotypic trait with clonality. KW - Infektionsbiologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59865 ER - TY - JOUR A1 - Hacker, Jörg A1 - Ott, M. A1 - Hof, H. T1 - Effects of low, subinhibitory concentrations of antibiotics on expression of a virulence gene cluster of pathogenic E. coli by using a wild-type gene fusion N2 - No abstract available KW - Infektionsbiologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59874 ER - TY - JOUR A1 - Morschhäuser, J. A1 - Uhlin, B. E. A1 - Hacker, Jörg T1 - Transcriptional analysis and regulation of the sfa determinant coding for S fimbria of pathogenic E. coli strains N2 - The sfa determinant codes for S fimbrial adhesins which constitute adherence factors of pathogenic Escherichia coli strains. Wehave recently shown that the sfa determinant is transcribed from three prömoters, pA, pB, and pC. In comparison with the promoters pB and pC, promoter pA, which is located in front of the structural gene sfaA, showed very weak activity. Herewe have determined the exact positions ofthe mRNA start points by primer extension studies. We have also shown that mRNAs of 500, 700 and 1400 bases can be detected using oligonucleotide probes specific for the genes sfaB, sfaC and sfaA. SfaB and SfaC arepositive regulators infiuencing fimbriation and the production of the S-specific adhesin which is encoded by the gene sfaS Iocated in the distal half of the determinant. In addition, it is demonstrated that SfaB and SfaC interfere with the regulatory effect of the histone-like protein H-NS, encoded by a locus termed drdX or osmZ. In a drdx+ strain the regulators are necessary for transcription of the sfa determinant. In contrast, sfa expression is activator-independent in a drdx- strain. In this latter genetic background, a substantial fraction of the sfa transcripts is initiated from promoter pA. On the basis of these data we discuss a model for the regulation of this adhesin-specific determinant. KW - Infektionsbiologie KW - Gene regulation KW - Fimbriae KW - Adhesion KW - Transcription KW - trans-activation Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59844 ER - TY - JOUR A1 - Kunin, Calvin M. A1 - Hua, Tong Hua A1 - Van Arsdale-White, Laura A1 - Krishnan, Chandradekar A1 - Hacker, Jörg T1 - Isolation of a nicotinamide-requiring clone of Escherichia coli O18:K1:H7 from women with acute cystitis resembles strains found in neonatal meningitis N2 - 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. Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40406 ER - TY - JOUR A1 - Hacker, Jörg A1 - Ott, Manfred A1 - Wintermeyer, Eva A1 - Ludwig, Birgit A1 - Fischer, Gunter T1 - Analysis of virulence factors of Legionella pneumophila. N2 - 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. KW - Legionella pneumophila Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-70620 ER - TY - JOUR A1 - Morschhäuser, Joachim A1 - Vetter, Viktoria A1 - Korhonen, Timo A1 - Uhlin, Bernt Eric A1 - Hacker, Jörg T1 - Regulation and binding properties of S fimbriae cloned from E. coli strains causing urinary tract infection and meningitis N2 - 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. KW - Escherichia coli KW - Harnwegsinfekt KW - Hirnhautentzündung Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86140 ER - TY - JOUR A1 - Linhardt, F. A1 - Ziebuhr, W. A1 - Meyer, P. A1 - Witte, W. A1 - Hacker, Jörg T1 - Pulsed-field gel electrophoresis of genomic restriction fragments as a tool for the epidemiological analysis of Staphylococcus aureus and coagulase-negative Staphylococci N2 - Thirtccn StttJ1hylococcus dw·eus and s: <'pid<'l'· midis strains ohtaincd from nnsc and hand nf twn cmployccs and onc paticnt uf a mcdical ward as weil as two S. hemol.\"licus strains wcrc analyscd according to thcir rcstrktion fmgmcnt lcngth pattcrns ( RFLP) hy pulscd-ficld gcl clcctrophorcsis (PFGE) using thc rcslriction cnzymcs SmaJ and s.. .· tll. Spccics idcntification nf thc isolatcs was pcrformcd hy a systcm which includcs :!O hiochcmical rc"ctions. Furthcrmorc. thc antillintic resistancc pattcrns of thc stmins wcrc dctcrmincd. Whilc scvcral isolatcs cxhihitcd idcnticaf antihiotic susccptihilitics and hiochcmical prnfilcs. diffcrences in thc RFLP wcrc ohtaincd. ln thrcc cascs, S. epidermülis strains colonizing thc skin showcd an idcntical rcstriction profilc as isollltcs from thc mucous mcmhrancs of thc samc pcrson. Wc C(mcludcd that thc analysis of staphylococcal strains hy PFGE is an important cpidcmiolngical tnnl with high discrimination power. KW - Infektionsbiologie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59811 ER - TY - JOUR A1 - Ott, M. A1 - Bender, L. A1 - Lück, P. C. A1 - Meyer, P. A1 - Hacker, Jörg T1 - Distribution of Legionellae in a hospital water system: prevalence of immunologically and genetically related Legionella pneumophila serogroup 6 isolates N2 - A hospital warm water system was monitored for the prcsence and distribution of lcgionellac. Subtyping of ten scletled Legionella pneumophiltl isolates. originating from four different sites in the system by using serogroup spccific antisera in an indircct immunofluorcscence tcst, rcvcalcd that nine of the tcn isolatcs belonged to scrogroup 6, while the remaining one was serogroup I 0. Two monoclonal antibodics (mAbs) spccific for a subgroup of serogroup 6 strains were further used for characterization. None of the strains reactcd with these mAbs. Genome analysis by elaborating Not I profiles using the pulscd field gel electrophoresis (PFGE) technique revealed that nearly all serogroup 6 isolates dcrived from different sites, including a new building connected hy a ring pipe. wcrc identical according to restriction fragment pattems. The patterns were distinguishable from those of the two L. pnewnophi/a serogroup 6 rcfcrencc strains, and ftom that of thc L. pneumophila scrogroup 10 isolate. These data arguc for a relatively homogeneaus L. pneunwpltila serogroup 6 population in the entire watcr system. KW - Infektionsbiologie KW - Legionella pneumophila KW - Hospital water system KW - Environmental isolate KW - Serogroup KW - Genomic profile Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59827 ER -