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Research Interests: Genetics, Microbiology, Biology, Molecular Microbiology, Medicine, and 15 moreSequence Analysis, Biological Sciences, Lipopolysaccharide, Molecular, Membrane transport proteins, Lipopolysaccharides, phospholipases A2, Molecular weight, Amino Acid Sequence, Campylobacter jejuni, Antigen, Serotyping, Serotype, Molecular Sequence Data, and Medical and Health Sciences
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Research Interests: Biology, Helicobacter pylori, Medicine, Humans, Female, and 14 moreNucleic acid hybridization, Male, Cluster Analysis, TYPING, ribosomal RNA, Recurrence, Middle Aged, Adult, Public health systems and services research, Peptic Ulcer, Ribosomal DNA, Duodenal Ulcer, restriction enzyme, and Restriction Mapping
Research Interests: Microbiology, Biology, Medicine, Biological Sciences, Polymerase Chain Reaction, and 11 moreNitrates, Nitrate Reductase, multiplex PCR, Phenotype, Genomic DNA, Genome sequence, Species Specificity, Campylobacter jejuni, Molecular Sequence Data, Medical and Health Sciences, and multiplex polymerase chain reaction
Research Interests: Microbiology, Molecular Evolution, Comparative Genomics, Biology, Medicine, and 15 moreBiological Sciences, Virulence, Phylogeny, Humans, Nucleic acid hybridization, Molecular Phylogenetics and Evolution, Phenotype, Genotype, Genetic variation, Indexation, Virulence Factors, Campylobacter jejuni, Multilocus sequence typing, Sequence homology, and Medical and Health Sciences
Research Interests: Molecular Biology, Biology, Natural History, Helicobacter pylori, Medicine, and 15 moreClinical Microbiology, Biological Sciences, Humans, Gastric Cancer, Agarose Gel Electrophoresis, Genomic DNA, Dental Plaque, Diagnostic Test, Gel electrophoresis, H Pylori, Duodenal Ulcer, DNA sequence, False Positive, Gastric mucosa, and Medical and Health Sciences
This chapter describes the microbiology, epidemiology, and clinical features of infection with Campylobacter species other than C. jejuni subsp. jejuni and C. coli that are associated with human disease. The major habitat of C. fetus is... more
This chapter describes the microbiology, epidemiology, and clinical features of infection with Campylobacter species other than C. jejuni subsp. jejuni and C. coli that are associated with human disease. The major habitat of C. fetus is the intestine, and it is commonly isolated from healthy sheep and cattle. C. fetus infections are often prolonged and result in relapse, but most patients will recover with appropriate antibiotic treatment and medical procedures. C. upsaliensis is a recognized human pathogen in both healthy and immunocompromised patients. C. hyointestinalis was identified and suggested as a possible cause of proliferative enteritis in pigs. Six Campylobacter species have an essential growth requirement for hydrogen or formate. A membrane-bound hemolytic phospholipase was detected and characterized in clinical strains of C. concisus isolated from Australian children with gastroenteritis. The presence of this potential virulence factor suggests C. concisus is an opportunistic pathogen. Two recent reviews summarize clinical presentation, pathogenicity, and other aspects of Arcobacter infection. The chapter also describes other Helicobacter and Campylobacter species. The clinical relevance of the newly recognized Campylobacter species has yet to be determined. PCR assays for the simultaneous detection and differentiation of the genera and individual species of Campylobacter, Helicobacter, and Arcobacter may make this task easier. Appreciation and application of an efficient protocol is essential for the isolation of non-jejuni, non-coli Campylobacter species for surveillance, epidemiological, and other studies.
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Research Interests: Microbiology, Immunology, Kinetics, Medical Microbiology, Biology, and 15 moreMacrophages, Medicine, Humans, Macrophage, Campylobacter, Bacteria, Catalase, Lipopolysaccharides, Bacterial growth, Bacteremia, Campylobacter jejuni, Medical Microbiology and Immunology, Macrophage activation, In Vitro Techniques, and Blood Donor
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The precise identification of unusual members of the genus Campylobacter is often problematic7. By and large, speciation is based on a few phenotypic tests that are not always reliable7. Alternative tools for identifying species are based... more
The precise identification of unusual members of the genus Campylobacter is often problematic7. By and large, speciation is based on a few phenotypic tests that are not always reliable7. Alternative tools for identifying species are based on the genotype rather than on the phenotype of an organism. Genotypic methods have been used to discriminate the thermophilic Campylobacter species1,2. Recently, a simple PCR-based method, the Amplification Refractory Mutation System (ARMS), for the characterization of DNA polymorphisms was described5. Where species specific base differences can be identified, the authors suggest that the technique might prove useful in the speciation of bacteria. The work described here evaluates ARMS in the identification of C.mucosalis, C.concisus and C.curvus, species that are impossible to differentiate by phenotypic tests alone4.
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To evaluate the Oxoid Biochemical Identification System (OBIS) Campy test (ID0800M) against Campylobacter; Arcobacter; and other micro-organisms, with similar colonial morphology, for the detection of l-alanine aminopeptidase (l-ALA). The... more
To evaluate the Oxoid Biochemical Identification System (OBIS) Campy test (ID0800M) against Campylobacter; Arcobacter; and other micro-organisms, with similar colonial morphology, for the detection of l-alanine aminopeptidase (l-ALA). The KOH and l-ALA (OBIS and Fluka) tests were carried out on every isolate. The procedures were followed as indicated in the OBIS and Fluka kit instructions. A total of 146 strains of 19 species of Campylobacter, seven strains of Arcobacter butzleri, four Arcobacter butzleri-like strains, 42 strains of 10 species of Helicobacter, 96 Gram-negative and 49 Gram-positive clinical isolates were tested. As expected, Campylobacter and Arcobacter strains were negative, while other Gram-negative bacteria were positive for the l-ALA test. An unexpected finding was that Helicobacter strains, although Gram-negative, were all negative for the l-ALA tests suggesting the absence of l-ALA within this genus. This is a novel finding. The absence of l-ALA was confirmed upon comparison with the available full genomic sequences of Helicobacter on the NCBI database. The OBIS Campy (ID0800M) test kit proved to be rapid and accurate for the presumptive characterization of Campylobacter and Arcobacter. A novel finding was that Helicobacter species also did not have the l-ALA enzyme. The OBIS kit will be useful in diagnostic laboratories for the presumptive diagnosis of Campylobacter, Arcobacter and Helicobacter strains.
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info:eu-repo/semantics/publishe
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Research Interests: Biology and Campylobacter
Duodenal ulcer relapse rates after therapy with sucralfate or bismuth are lower than those after H2-receptor antagonist therapy. This may be mediated by an antibacterial effect of these drugs on Helicobacter pylori. Bismuth has become an... more
Duodenal ulcer relapse rates after therapy with sucralfate or bismuth are lower than those after H2-receptor antagonist therapy. This may be mediated by an antibacterial effect of these drugs on Helicobacter pylori. Bismuth has become an integral part of 'triple therapy' because of its documented anti-H. pylori effect. In vitro and clinical data suggest that sucralfate may also have an anti-H. pylori effect. The aim of this randomized, prospective therapeutic trial was to compare the efficacy of triple therapy containing bismuth with that containing sucralfate and to determine the effect of therapy with these combinations on duodenal ulcer relapse. Forty H. pylori-positive duodenal ulcer patients were healed with omeprazole and randomized to receive either 1 g sucralfate four times daily or 120 mg bismuth compound four times daily. All patients received 400 mg metronidazole three times daily and either 250 or 500 mg tetracycline four times daily for 7-14 days. Thirty-five patients could be analysed. Overall eradication rates did not differ in the treatment groups (10 of 17 eradicated with sucralfate and 11 of 18 with bismuth). Relapse rates were significantly lower in the eradicated group (1 of 21 compared with 8 of 14 in the non-eradicated group) and did not differ between treatment groups in those patients not eradicated. A triple therapy regimen utilizing sucralfate appears to be as effective as the bismuth-containing regimen.
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DNA fingerprinting using (GTG)(5) oligonucleotide as a primer in a random amplified polymorphic DNA (RAPD) assay was assessed by typing isolates of Campylobacter concisus strains, collected over a period of 8 years. RAPD analysis using... more
DNA fingerprinting using (GTG)(5) oligonucleotide as a primer in a random amplified polymorphic DNA (RAPD) assay was assessed by typing isolates of Campylobacter concisus strains, collected over a period of 8 years. RAPD analysis using the (GTG)(5) oligonucleotide as a primer was used to type 100 isolates of C. concisus comprising mostly isolates from children with diarrhoea. Using this method, 86% of the isolates were found to be genotypically diverse. Of these heterogeneous isolates, 25 of the strains were also shown to be genetically distinct in a previous study using pulsed field gel electrophoresis. The remaining isolates (14) could be classified into five profile groups based on the DNA fingerprinting patterns. The assay successfully identified epidemiologically linked strains from the unrelated genetically diverse pool of strains. Laboratory RADP typing using the (GTG)(5) primer proved to be useful in distinguishing related strains of C. concisus from a large pool of unrelated strains of this organism. RAPD typing using (GTG)(5) is a simple method that could be used to investigate the epidemiology of C. concisus. The results suggest that homologous lineages of C. concisus may exist within an otherwise heterogeneous species complex. However, these data need to be confirmed using a more robust typing method.
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Antibodies reactive with GM~ ganglioside and structurally related glycolipids are frequently observed in the serum of patients with peripheral neuropathies. The precise relationship between these anti-ganglioside antibodies and disease... more
Antibodies reactive with GM~ ganglioside and structurally related glycolipids are frequently observed in the serum of patients with peripheral neuropathies. The precise relationship between these anti-ganglioside antibodies and disease pathogenesis remains unknown. ...
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The in vitro susceptibility of 41 strains of "Campylobacter upsaliensis" to 24 antimicrobial agents was determined using a broth microdilution procedure. Most isolates were susceptible to the fluoroquinolones and... more
The in vitro susceptibility of 41 strains of "Campylobacter upsaliensis" to 24 antimicrobial agents was determined using a broth microdilution procedure. Most isolates were susceptible to the fluoroquinolones and beta-lactam antibiotics tested, but all strains were resistant to trimethoprim (MBCs greater than or equal to 128 micrograms/ml) and teicoplanin (MBCs greater than or equal to 32 micrograms/ml). These agents may be useful in a selective isolation medium for "Campylobacter upsaliensis".
Research Interests: Microbiology, Biology, Medicine, Biological Sciences, Dogs, and 15 moreHumans, Campylobacter, Animals, Quinolones, Antimicrobial, Antibiotics, Anti-Bacterial Agents, Microbial Sensitivity Tests, Teicoplanin, Glycopeptides, lactams, Medical and Health Sciences, Antimicrobial agent, Trimethoprim, and Broth Microdilution
Research Interests: Microbiology, Medicine, Antibiotic Resistance, Humans, Campylobacter, and 11 moreMicrobial genetic and drug resistance, Infant, Diarrhoeal disease, Antimicrobial, Clinical Sciences, Antibiotics, Public health systems and services research, Allium Sativum, Nalidixic acid, Allicin, and Paediatrics and reproductive medicine
SUMMARYThe effect of Helicobacter pylori lipopolysaccharide on guinea pig gastric mucosal pepsinogen secretion has been examined using an Ussing chamber technique. Luminal addition of H. pylori lipopolysaccharide resulted in a fifty‐fold... more
SUMMARYThe effect of Helicobacter pylori lipopolysaccharide on guinea pig gastric mucosal pepsinogen secretion has been examined using an Ussing chamber technique. Luminal addition of H. pylori lipopolysaccharide resulted in a fifty‐fold stimulation of pepsinogen secretion compared to a twelve‐fold increase with E. coil lipopolysaccharide. Electron microscopy showed marked degranulation of zymogen granules but no evidence of chief cell disruption.
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A 1.6-kb DNA fragment isolated from a Campylobacter concisus genomic library gave C. concisus -specific restriction fragment length patterns when it was used as a probe in hybridization studies. All of the strains tested, including type... more
A 1.6-kb DNA fragment isolated from a Campylobacter concisus genomic library gave C. concisus -specific restriction fragment length patterns when it was used as a probe in hybridization studies. All of the strains tested, including type strains and clinical isolates, contained a 0.5-kb Hin dIII fragment that hybridized to the probe. DNA sequencing of the 1.6-kb fragment identified three open reading frames (ORFs). One of the ORFs encodes the carboxy terminus of GyrB, and the translational products of ORF2 and ORF3 showed similarity to hypothetical proteins, previously identified in Campylobacter jejuni . DNA-DNA hybridization studies with a fragment internal to ORF3 showed that this sequence was responsible for the signal observed with the 0.5-kb Hin dIII fragment. A rapid PCR assay was developed and evaluated. Primers that annealed to the extremities of the 1.6-kb fragment were used to obtain an amplicon of the correct size from both reference and clinical strains of C. concisus .
Research Interests: Genetics, Molecular Biology, Biology, Medicine, Clinical Microbiology, and 15 moreBiological Sciences, DNA, Humans, Child, Campylobacter, Clinical, Nucleic acid hybridization, Polymerase Chain Reaction, Genomic DNA, Adult, Species Specificity, Amplicon, DNA probes, Molecular Sequence Data, and Medical and Health Sciences
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Research Interests: Genetics, Polymorphism, Medicine, Antibiotic Resistance, Clinical Microbiology, and 15 moreBiological Sciences, Inflammatory Bowel Disease, Humans, Child, Campylobacter, Female, Male, DNA hybridization, Liver Transplantation, Middle Aged, Adult, Membrane Filtration, Clinical Presentation, Biliary Atresia, and Medical and Health Sciences
The ability of Campylobacter jejuni to survive in monocytes after phagocytic uptake was tested in a new in vitro model using adherent macrophages derived from human peripheral monocytes. The cells were stimulated with cytokines before use... more
The ability of Campylobacter jejuni to survive in monocytes after phagocytic uptake was tested in a new in vitro model using adherent macrophages derived from human peripheral monocytes. The cells were stimulated with cytokines before use to ensure full phagocytic and killing activity. The kinetics of uptake and killing of bacteria was followed for 72 h with 16 strains, including stool and blood isolates and laboratory adapted strains. Significant bacterial strain differences were not observed, but the viability of phagocytosed bacteria was dependent on the individual donating the macrophages. The majority of blood donors carried macrophages that killed phagocytosed Campylobacter within 24 or 48 h. There was no correlation between the source of isolation of the strains and relative intracellular survival. Bacterial mutants of superoxide dismutase, catalase or polyphosphate kinase were all as sensitive to macrophage killing as their isogenic wild-type strain. In contrast, about 10% o...
Research Interests: Immunology, Kinetics, Medical Microbiology, Macrophages, Humans, and 13 moreMutation, Catalase, Superoxide Dismutase, Lipopolysaccharides, Phagocytosis, Monocytes, Bacterial growth, Bacteremia, Campylobacter jejuni, Medical Microbiology and Immunology, Macrophage activation, In Vitro Techniques, and Blood Donor
BackgroundCampylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry... more
BackgroundCampylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS). This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP) approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular.ResultsWe compared 6 different isolates of the "genome strain" NCTC 11168 obtained from different laboratories. HtAFLP analysis generated approximately 3000 markers per stain, 19 of which were polymorphic. The DNA polymorphisms could not be confirmed by PCR-RFLP analysis, suggesting a baseline level of 0.6% AFLP artefacts. Comparison of NCTC 11168 with 4 GBS-associated strains revealed 23 potentially GBS-specific markers, 17 of which were identified by DNA sequencing. A collection...
Research Interests: Genetics, Microbiology, Biological Sciences, DNA, Lipopolysaccharide, and 15 moreHumans, Lipopolysaccharides, Molecular Mimicry, Genetic Polymorphism, Bacterial genetics, Genetic variation, Bacterial Genetics, Base Sequence, Genetic Markers, Campylobacter jejuni, Gangliosides, DNA polymorphism, Miller Fisher syndrome, DNA sequence, and Medical and Health Sciences
Latex agglutination tests for the rapid identification of Campylobacter spp. have been available in the market for more than 20 years ([1][1], [3][2]). As of November 2007, there were only three commercial latex agglutination tests:... more
Latex agglutination tests for the rapid identification of Campylobacter spp. have been available in the market for more than 20 years ([1][1], [3][2]). As of November 2007, there were only three commercial latex agglutination tests: PanBio-Campy (jcl) (PanBio Inc., Columbia, MD), the Dryspot
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A multilocus sequence typing (MLST) system has been reported previously for Campylobacter jejuni to both differentiate strains and identify clonal lineages. However, sequence variation at the MLST loci prevents its use for closely related... more
A multilocus sequence typing (MLST) system has been reported previously for Campylobacter jejuni to both differentiate strains and identify clonal lineages. However, sequence variation at the MLST loci prevents its use for closely related Campylobacter species. We describe herein an expanded MLST method to include three clinically relevant Campylobacter species, C. coli, C. lari, and C. upsaliensis, and a fourth Campylobacter species, C. helveticus. The C. coli and C. helveticus methods use the same seven C. jejuni loci (aspA, atpA, glnA, gltA, glyA, pgm, and tkt); however, adk and pgi were substituted for aspA and gltA in C. lari and for gltA and pgm in C. upsaliensis. Multiple C. coli (n = 57), C. lari (n = 20), C. upsaliensis (n = 78), and C. helveticus (n = 9) isolates, representing both clinical and environmental sources, were typed. All four species were genetically diverse: the majority (>80%) of the isolates had unique sequence types (STs). Using this method, mixed C. lar...
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We report the complete genome sequence of the Campylobacter concisus type strain ATCC 33237 and the draft genome sequences of eight additional well-characterized C. concisus strains. C. concisus has been shown to be a genetically... more
We report the complete genome sequence of the Campylobacter concisus type strain ATCC 33237 and the draft genome sequences of eight additional well-characterized C. concisus strains. C. concisus has been shown to be a genetically heterogeneous species, and these nine genomes provide valuable information regarding the diversity within this taxon.
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Summary The suitability of sodium dodecyl sulfate-polyacrylamide gel electrophoretic protein profiles coupled to a computer-assisted numerical analysis for the differentiation of helicobacters was evaluated. Fifty-three strains... more
Summary The suitability of sodium dodecyl sulfate-polyacrylamide gel electrophoretic protein profiles coupled to a computer-assisted numerical analysis for the differentiation of helicobacters was evaluated. Fifty-three strains representing most of the known and available species of Helicobacter and reference strains of allied taxa were included. The results indicate, (i) that the majority of the species examined by this technique could be clearly differentiated, including H. cinaedi and H. fennelliae , which can be difficult to separate by conventional bacteriological methods; two species, H. acinonyx and H. pylori constitute a single phenon at the 69% similarity level and cannot be distinguished at this level, (ii) that gastric helicobacters were more closely clustered to each other than they were to those of enteric origin, (iii) that within several species, different electrophoretic types could be distinguished and that, in the case of the H. pylori/H. acinonyx complex, there appeared to be clustering based on the host source of the strains. Two minor groups (one of human and one of canine origin) were identified and these may merit further phylogenetic analysis.
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ABSTRACT During the period January 1971 to July 1976, over 240 strains of Naegleria, Acanthamoeba and other limax amoebae were isolated from a variety of habitats in South Africa and South West Africa. Seven strains of Naegleria fowleri... more
ABSTRACT During the period January 1971 to July 1976, over 240 strains of Naegleria, Acanthamoeba and other limax amoebae were isolated from a variety of habitats in South Africa and South West Africa. Seven strains of Naegleria fowleri and a strain of Acanthamoeba were isolated from a heavily polluted section of the Eerste River, Cape Province, South Africa. These 8 isolates have been identified as being potentially pathogenic, the first such report for Africa.Limax amoebae have been discovered in previously undescribed habitats. Naegleria was found in marine mud and Acanthamoeba was isolated from desert sand. Both Naegleria and Acanthamoeba have been found in the alimentary tract of the clawed toad Xenopus laevis and in the faeces of the black duck Anas sparsa. These animals may act as vectors for the transmission of limax amoebae from one site to another.
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Forty strains of H. fennelliae collected from paediatric blood and stool samples over an 18 year period at a children's hospital in Cape Town, South Africa, were amplified by PCR of the 16S rRNA. Two distinct genotypes of H.... more
Forty strains of H. fennelliae collected from paediatric blood and stool samples over an 18 year period at a children's hospital in Cape Town, South Africa, were amplified by PCR of the 16S rRNA. Two distinct genotypes of H. fennelliae were identified based on the phylogenetic analysis. This was confirmed by sequencing a portion of the beta subunit of the RNA polymerase (rpoB) gene. All isolates from South Africa clustered with a proposed novel Helicobacter strain (accession number AF237612) isolated in Australia, while three H. fennelliae type strains from the northern hemisphere, NCTC 11612, LMG 7546 and CCUG 18820, formed a separate branch. A large (355bp) highly conserved intervening sequence (IVS) in the 16S rRNA was found in all isolates. Predicted secondary structures of the IVS from the 16S rRNA and 23S rRNA were characterised by a primary stem structure formed by base pairing of the 3' and 5' ends and internal loops and stems. This phylogenetic analysis is the l...
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Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human... more
Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS). This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP) approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular. We compared 6 different isolates of the "genome strain" NCTC 11168 obtained from different laboratories. HtAFLP analysis generated approximately 3000 markers per stain, 19 of which were polymorphic. The DNA polymorphisms could not be confirmed by PCR-RFLP analysis, suggesting a baseline level of 0.6% AFLP artefacts. Comparison of NCTC 11168 with 4 GBS-associated strains revealed 23 potentially GBS-specific markers, 17 of which were identified by DNA sequencing. A collection of 27 GBS/MFS-a...
Research Interests: Genetics, Microbiology, Biological Sciences, DNA, Lipopolysaccharide, and 15 moreHumans, Lipopolysaccharides, Genetic Polymorphism, Bacterial genetics, Genetic variation, Bacterial Genetics, Base Sequence, Genetic Markers, Campylobacter jejuni, Gangliosides, DNA polymorphism, Miller Fisher syndrome, DNA sequence, BMC, and Medical and Health Sciences
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Campylobacter jejuni O:41 strains are found in association with Guillain-Barré syndrome in South Africa. Strains of this serotype collected over 17 years were characterized by amplified fragment length polymorphism and flagellin typing to... more
Campylobacter jejuni O:41 strains are found in association with Guillain-Barré syndrome in South Africa. Strains of this serotype collected over 17 years were characterized by amplified fragment length polymorphism and flagellin typing to determine their clonal nature. Despite minor variation in GM1 expression, all of the strains were genetically indistinguishable, indicating that they are representative of a genetically stable clone.