Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specificity of serological tests for Lyme borreliosis is impaired by cross-reacting antibodies. In order to select antigens for more specific tests, specific and cross-reactive proteins of Borrelia burgdorferi must be identified. Therefore, to analyze cross reactions of Borrelia burgdorferi with other bacteria, rabbit immune sera against heterologous bacteria (Borrelia hermsii, Treponema pallidum, Treponema phagedenis, Leptospira interrogans (serogroup grippotyphosa), Neisseria meningitidis, Haemophilus influenzae, Yersinia enterocolitica (serotypes O3 and O9), Campylobacter jejuni, Listeria monocytogenes O1, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium, Shigella flexneri and Legionella micdadei) were examined by Western blot using Borrelia burgdorferi as antigen. Broad cross reactivity was shown for Borrelia proteins of the 60-75 kDa range. Other broadly cross-reacting proteins were at the level of p40, p33 and two proteins in the range of 20 kDa. Some of the cross reactions were eliminated by absorption of the sera with Treponema phagedenis. The absorbed antibodies were directed mainly against bands at the level of p33 and bands of the 60 to 75 kDa range. Showing the lowest potential for cross reactivity, p100, p41, OspA and pC seem to be the most suitable antigens for serodiagnosis. In contrast to p100 and OspA, however, p41 and pC showed cross reactivity with immune sera against bacteria not belonging to the genus Borrelia.
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PMID:Cross-reactive proteins of Borrelia burgdorferi. 159 98

Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of iron-deficient and replete cell envelopes, 59Fe-siderophore uptake studies, and Western immunoblots and cytofluorimetric analyses with monoclonal antibodies (MAbs), we surveyed a panel of gram-negative bacteria to identify outer membrane proteins that are structurally related to the Escherichia coli K-12 ferric enterobactin receptor, FepA. Antibodies within the panel identified FepA epitopes that are conserved among the majority of the bacteria tested, as well as epitopes present in only a few of the strains. In general, epitopes of FepA that are buried in the outer membrane bilayer were more conserved among gram-negative bacteria than epitopes that are exposed on the bacterial cell surface. The surface topology and tertiary structure of FepA are quite similar in E. coli and Shigella flexneri but differ in Salmonella typhimurium. Of the 18 different genera tested, 94% of the bacteria transported ferric enterobactin, including members of the previously unrecognized genera Citrobacter, Edwardsiella, Enterobacter, Haemophilus, Hafnia, Morganella, Neisseria, Proteus, Providencia, Serratia, and Yersinia. The ferric enterobactin receptor contains at least one buried epitope, recognized by MAb 2 (C. K. Murphy, V. I. Kalve, and P. E. Klebba, J. Bacteriol. 172:2736-2746, 1990), that is conserved within the structure of an iron-regulated cell envelope protein in all the bacteria that we have surveyed. With MAb 2, we identified and determined the Mr of cell envelope antigens that are immunologically related to E. coli FepA in all the gram-negative bacteria tested. Collectively, the library of anti-FepA MAbs showed unique patterns of reactivity with the different bacteria, allowing identification and discrimination of species within the following gram-negative genera: Aeromonas, Citrobacter, Edwardsiella, Enterobacter, Escherichia, Haemophilus, Hafnia, Klebsiella, Morganella, Neisseria, Proteus, Providencia, Pseudomonas, Salmonella, Serratia, Shigella, Vibrio, and Yersinia.
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PMID:Evolution of the ferric enterobactin receptor in gram-negative bacteria. 171 34

A large number of structurally diverse di- and tripeptides containing the alanine racemase inactivator beta-chloro-L-alanine (beta-Cl-LAla) have been synthesized, and their antibacterial properties in vitro have been evaluated. The dipeptides 1, 3-6, and 8-17 and the tripeptide 20 are all broad-spectrum antibacterial agents with considerable potency against both Gram-positive and Gram-negative species, but none of these peptides improves dramatically on the antibiotic efficacy of the previously described beta-Cl-LAla-beta-Cl-LAla, 9 (Cheung, K. S.; Wasserman, S. A.; Dudek, E.; Lerner, S. A.; Johnston, M. J. Med. Chem. 1983, 26, 1733). Gram-negative microorganisms, such as Escherichia coli, Hemophilus influenzae, Shigella flexneri, and Enterobacter species are consistently resistant to any haloalanyl peptide containing an alanyl residue, such as the dipeptide LAla-beta-Cl-LAla (2) and the tripeptides LMet-LAla-beta-Cl-LAla (7), LAla-LAla-beta-Cl-LAla (18), and LVal-LAla-beta-Cl-LAla (19). Correspondingly, these same organisms are protected from the bactericidal effects of 9 by supplementation of the growth medium with LAla or LAla-LAla. Escherichia coli JSR-O exposed to 9, but protected from lysis by sucrose stabilization, has only about 10% the normal level of intracellular alanine racemase activity. But when these cells are cultured in the presence of 9 with LAla supplementation, or in the presence of 2 with no supplementation, the alanine racemase levels are only about 20-30% below control values. These findings suggest that the resistance of Gram-negative species to chloroalanyl peptides containing alanyl units arises from the ability of LAla to protect the targeted racemase from inactivation by beta-Cl-LAla in vivo, an event which otherwise leads to cell death and lysis. Inactivation of alanine racemase in Gram-positive organisms appears not to be the cellular event that confers sensitivity of these species to a haloalanyl peptide.
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PMID:Chloroalanyl antibiotic peptides: antagonism of their antimicrobial effects by L-alanine and L-alanyl peptides in gram-negative bacteria. 309 82

Enteropathogenic Escherichia coli (EPEC) secretes at least five proteins. Two of these proteins, EspA and EspB (previously called EaeB), activate signal transduction pathways in host epithelial cells. While the role of the other three proteins (39, 40, and 110 kDa) remains undetermined, secretion of all five proteins is under the control of perA, a known positive regulator of several EPEC virulence factors. On the basis of amino-terminal protein sequence data, we cloned and sequenced the gene which encodes the 110-kDa secreted protein and examined its possible role in EPEC signaling and interaction with epithelial cells. In accordance with the terminology used for espA and espB, we called this gene espC, for EPEC-secreted protein C. We found significant homology between the predicted EspC protein sequence and a family of immunoglobulin A (IgA) protease-like proteins which are widespread among pathogenic bacteria. Members of this protein family are found in avian pathogenic Escherichia coli (Tsh), Haemophilus influenzae (Hap), and Shigella flexneri (SepA). Although these proteins and EspC do not encode IgA protease activity, they have considerable homology with IgA protease from Neisseria gonorrhoeae and H. influenzae and appear to use a export system for secretion. We found that genes homologous to espC also exist in other pathogenic bacteria which cause attaching and effacing lesions, including Hafnia alvei biotype 19982, Citrobacter freundii biotype 4280, and rabbit diarrheagenic E. coli (RDEC-1). Although these strains secrete various proteins similar in molecular size to the proteins secreted by EPEC, we did not detect secretion of a 110-kDa protein by these strains. To examine the possible role of EspC in EPEC interactions with epithelial cells, we constructed a deletion mutant in espC by allelic exchange and characterized the mutant by standard tissue culture assays. We found that EspC is not necessary for mediating EPEC-induced signal transduction in HeLa epithelial cells and does not play a role in adherence or invasion of tissue culture cells.
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PMID:Characterization of EspC, a 110-kilodalton protein secreted by enteropathogenic Escherichia coli which is homologous to members of the immunoglobulin A protease-like family of secreted proteins. 893 11

The large virulence plasmid pMYSH6000 of Shigella flexneri contains a replicon and a plasmid maintenance stability determinant (Stb) on adjacent SalI fragments. The presence of a RepFIIA replicon on the SalI C fragment was confirmed, and the complete sequence of the adjacent SalI O fragment was determined. It shows homology to part of the transfer (tra) operon of the F plasmid. Stb stabilizes a partition-defective P1 miniplasmid in Escherichia coli. A 1.1-kb region containing a homolog of the F trbH gene was sufficient to confer stability. However, the trbH open reading frame could be interrupted without impairing stability. Deletion analysis implicated the involvement of two small open reading frames, STBORF1 and STBORF2, that fully overlap trbH in the opposite direction. These open reading frames are closely related to the vagC and vagD genes of the Salmonella dublin virulence plasmid and to open reading frame pairs in the F trbH region and in the chromosomes of Dichelobacter nodosus and Haemophilus influenzae. Stb appears to promote better-than-random distribution of plasmid copies and is a plasmid incompatibility determinant. The F homolog does not itself confer stability but exerts incompatibility against the activity of the Stb system. Stb is likely to encode either an active partition system or a postsegregational killing system. It shows little similarity to previously studied plasmid stability loci, but the genetic organization of STBORF1 and STBORF2 resembles that of postsegregational killing mechanisms.
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PMID:Plasmid maintenance functions of the large virulence plasmid of Shigella flexneri. 917 15

The she gene of Shigella flexneri 2a, which also harbors the internal enterotoxin genes set1A and set1B (F. R. Noriega, GenBank accession no. U35656, 1995) encodes a homolog of the virulence-related immunoglobulin A (IgA) protease-like family of secreted proteins, Tsh, EspC, SepA, and Hap, from an avian pathogenic Escherichia coli, an enteropathogenic E. coli, S. flexneri 5, and Haemophilus influenzae, respectively. To investigate the possibility that this locus was carried on a larger deletable element, the S. flexneri 2a YSH6000T she gene was insertionally disrupted by allelic exchange using a Tn10-derived tetAR(B) cassette. Then, to detect loss of the she locus, the tetracycline-resistant derivative was plated onto fusaric acid medium to select for tetracycline-sensitive revertants, which were observed to arise at a frequency of 10(-5) to 10(-6). PCR and pulsed-field gel electrophoresis analysis confirmed loss of the she::tetAR(B) locus in six independent tetracycline-sensitive isolates. Sample sequencing over a 25-kb region flanking she identified four insertion sequence-like elements, the group II intron-like sequence Sf.IntA, and the 3' end of a second IgA protease-like homolog, sigA, lying 3.6 kb downstream and in an orientation inverted with respect to she. The deletion was mapped to chromosomal NotI fragment A and determined to have a size of 51 kb. Hybridization with flanking probes confirmed that at least 17.7 kb of the 51-kb deletable element was unique to the seven she+ strains investigated, supporting the conclusion that she lay within a large pathogenicity island. The method described in this study, termed island probing, provides a useful tool to further the study of pathogenicity islands in general. Importantly, this approach could also be of value in constructing safer live attenuated bacterial vaccines.
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PMID:Use of a novel approach, termed island probing, identifies the Shigella flexneri she pathogenicity island which encodes a homolog of the immunoglobulin A protease-like family of proteins. 935 40

We reported earlier that a single gene, tsh, isolated from a strain of avian pathogenic Escherichia coli (APEC) was sufficient to confer on E. coli K-12 a hemagglutinin-positive phenotype and that the deduced sequence of the Tsh protein shared homology to the serine-type immunoglobulin A (IgA) proteases of Neisseria gonorrhoeae and Haemophilus influenzae. In this report we show that E. coli K-12 containing the recombinant tsh gene produced two proteins, a 106-kDa extracellular protein and a 33-kDa outer membrane protein, and was also able to agglutinate chicken erythrocytes. N-terminal sequence data indicated that the 106-kDa protein, designated Tshs, was derived from the N-terminal end of Tsh after the removal of a 52-amino-acid N-terminal signal peptide, while the 33-kDa protein, designated Tshbeta, was derived from the C-terminal end of Tsh starting at residue N1101. The Tshs domain contains the 7-amino-acid serine protease motif that includes the active-site serine (S259), found also in the secreted domains of the IgA proteases. However, site-directed mutagenesis of S259 did not abolish the hemagglutinin activity or the extracellular secretion of Tshs indicating that host-directed proteolysis was mediating the release of Tshs. Studies with an E. coli K-12 ompT mutant strain showed that the surface protease OmpT was not needed for the secretion of Tshs. Tsh belongs to a subclass of the IgA protease family, which also includes EspC of enteropathogenic E. coli, EspP of enterohemorragic E. coli, and SepA and VirG of Shigella flexneri, which seem to involve a host endopeptidase to achieve extracellular release of their N-terminal domains. In proteolytic studies conducted in vitro, Tshs did not cleave the substrate of the IgA proteases, human IgA1 or chicken IgA, and did not show proteolytic activity in a casein-based assay. Correlation of Tsh expression and hemagglutination activity appears to be a very complex phenomenon, influenced by strain and environmental conditions. Nevertheless, for both APEC and recombinant E. coli K-12 strains containing the tsh gene, it was only the whole bacterial cells and not the cell-free supernatants that could confer hemagglutinin activity. Our results provide insights into the expression, secretion, and proteolytic features of the Tsh protein, which belongs to the growing family of gram-negative bacterial extracellular virulence factors, named autotransporters, which utilize a self-mediated mechanism to achieve export across the bacterial cell envelope.
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PMID:Characterization of the avian pathogenic Escherichia coli hemagglutinin Tsh, a member of the immunoglobulin A protease-type family of autotransporters. 991 89

Numerous outer membrane components of Neisseria meningitidis and N. gonorrhoeae exhibit phase variable expression (the rapid, reversible on/off switching of phenotypic expression). Many of the genes encoding these outer membrane components contain simple repetitive DNA motifs (mononucleotides, dinucleotides, tetranucleotides and other repeats) which mediate this variation. One such repeat motif, the tetranucleotide 5;-(GCAA)n-3;, is associated with phase-variable LPS biosynthetic genes in the pathogen Haemophilus influenzae. We have previously shown that N. meningitidis strain MC58 contains this repeat motif in at least three distinct genetic loci. In this study all three of these loci were investigated: two were cloned and identified as novel loci and designated nmrep1 and nmrep2. The third locus was assigned to a previously cloned gene and here is designated nmrep3. The distribution of these loci, and the number of repeat units at each locus was investigated in a range of strains. This analysis revealed that the nmrep1 and nmrep2 loci are present in all 45 strains examined, with 41/45 containing nmrep3. Sequences associated with nmrep1 showed no homology with reported proteins, but amino acid sequences of open reading frames of nmrep2 and nmrep3 exhibited sequence homology to the adhesins Aida of Escherichia coli and Prn of Bordetella sppand IcsA of Shigella flexneri which is involved in intracellular spread.
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PMID:Tetranucleotide repeats identify novel virulence determinant homologues in Neisseria meningitidis. 997 77

The in vitro activity of trovafloxacin (TRV) has been evaluated in comparison with that of other antimicrobial agents against 5671 clinical isolates recovered by representative institutions of different provinces in our country. The resistance percentage to gentamicin and third generation cephalosporins among enterobacteriaceae was high: 17% and 16% respectively, with a considerable variation according to the analyzed species. The resistance to ciprofloxacin (CIP) and TRV affected approximately 9% of the isolates, without significant differences between both drugs. Fluoroquinolones (FQ) presented excellent activity on 166 isolates of Salmonella spp., 208 of Shigella flexneri and 76 of Shigella sonnei, where only one S.sonnei isolate was resistant to CIP, but susceptible to TRV. About half the isolates of Salmonella spp. and S.sonnei and almost all S.flexneri isolates were resistant to ampicillin, and more than 60% of Shigella spp. isolates were resistant to trimethoprim-sulfamethoxazole. A 41% of Staphylococcus aureus and 55% of coagulase-negative staphylococci isolates were resistant to oxacillin, presenting a highly associated multi-resistance. The resistance to FQ was also strongly related to oxacillin resistance, but the resistance to TRV was significantly lower than the CIP resistance: 9% vs 57% for S.aureus and 4% vs 41% for coagulase-negative staphylococci. A similar behavior was observed with Enterococcus spp., where 54% of the isolates were resistant to norfloxacin and only 13% were resistant to TRV. Neither Streptococcus pneumoniae (n = 193) nor Haemophilus influenzae (n = 139) isolates presented resistant to TRV.
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PMID:[In vitro activity of trovafloxacin, of other fluoroquinolones and of related antimicrobials against clinical isolates. Grupo colaborativo WHONET-Argentina]. 1043 49

The World Health Organization has implemented a surveillance program for antimicrobial resistance that is known as WHONET. In Argentina the program was developed through a network of 23 public and private hospitals that participate in national and international quality-control programs. Between January 1995 and December 1996, the antimicrobial susceptibility of 16,073 consecutive clinical isolates was determined, using the recommended standards of the National Committee for Clinical Laboratory Standards of the United States of America. More than half of the Escherichia coli urinary isolates were resistant to ampicillin and more than 30% to trimethoprim/sulfamethoxazole (SXT). When the percentage of resistant isolates from outpatients (OPs) was compared to that observed in hospitalized patients (HPs), a marked difference in antimicrobial activity was noted in the case of gentamicin (2% from OPs resistant vs. 8% from HPs resistant), norfloxacin (2% vs. 6%), and third-generation cephalosporins (7% vs. 15%). Of the Klebsiella pneumoniae isolates recovered from blood cultures, 71% and 60% showed resistance to third-generation cephalosporins and to gentamicin, respectively. The overall rate of oxacillin resistance in Staphylococcus aureus was 39%. Around half of the Enterococcus spp. isolates showed high resistance to aminoglycosides, but resistance to glycopeptides was not found. In Argentina, ampicillin and SXT were not suitable for treating diarrhea. Shigella flexneri had a higher number of isolates resistant to both of those drugs (87% and 74%, respectively) than Sh. sonnei did (47% and 71%, respectively). About 40% of the Salmonella spp. isolated in pediatric hospitals were resistant to third-generation cephalosporins. When microorganisms causing bacterial meningitis were examined, Streptococcus pneumoniae showed a resistance rate of 18% to penicillin and Haemophilus influenzae a resistance rate of 19% to ampicillin. These rates are within the intermediate range reported for other countries of the Americas and for Europe.
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PMID:[Monitoring antibiotic resistance in Argentina. The WHONET program, 1995-1996]. 1057 73


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