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Billy Bourke - One of the best experts on this subject based on the ideXlab platform.

  • Invasion of human epithelial cells by Campylobacter Upsaliensis.
    Cellular microbiology, 2003
    Co-Authors: Adele Mooney, Philip M. Sherman, Catherine Byrne, Marguerite Clyne, Kathene C. Johnson-henry, Billy Bourke
    Abstract:

    Summary Few data exist on the interaction of Campylobacter Upsaliensis with host cells, and the potential for this emerging enteropathogen to invade epithelial cells has not been explored. We have characterized the ability of C. Upsaliensis to invade both cultured epi- thelial cell lines and primary human small intestinal cells. Epithelial cell lines of intestinal origin appeared to be more susceptible to invasion than non- intestinal-derived cells. Of three bacterial isolates studied, a human clinical isolate, CU1887, entered cells most efficiently. Although there was a trend towards more efficient invasion of Caco-2 cells by C. Upsaliensis CU1887 at lower initial inocula, actual numbers of intracellular organisms increased with increasing multiplicity of infection and with prolonged incubation period. Confocal microscopy revealed C. Upsaliensis within primary human small intestinal cells. Both Caco-2 and primary cells in non-confluent areas of the infected monolayers were substantially more susceptible to infection than confluent cells. The specific cytoskeletal inhibitors cytochalasin B, cytochalasin D and vinblastine attenuated invasion of Caco-2 cells in a concentration-dependent manner, providing evidence for both microtubule- and microfil- ament-dependent uptake of C. Upsaliensis . Electron microscopy revealed the presence of organisms within Caco-2 cell cytoplasmic vacuoles. C. upsalien- sis is capable of invading epithelial cells and appears to interact with host cell cytoskeletal structures in order to gain entry to the intracellular environment. Entry into cultured primary intestinal cells ex vivo provides strong support for the role of host cell inva- sion during human enteric C. Upsaliensis infection.

  • Basis of the superiority of cefoperazone amphotericin teicoplanin for isolating Campylobacter Upsaliensis from stools.
    Journal of clinical microbiology, 2001
    Co-Authors: Catherine Byrne, David L. Woodward, Adele Mooney, Deirdre Doherty, Margaret Byrne, Wendy M. Johnson, Frank G. Rodgers, Billy Bourke
    Abstract:

    The optimum method for isolating Campylobacter Upsaliensis from stools has not been clearly defined. In a preliminary study, cefoperazone amphotericin teicoplanin (CAT) selective medium isolated six C. Upsaliensis strains which were not detected using modified cefoperazone charcoal deoxycholate (mCCDA). In order to identify the factors that underlie the superiority of CAT over mCCDA for isolating C. Upsaliensis, we examined the effect of incubation time and antibiotic content of culture media on the growth of C. Upsaliensis isolates using semiquantitative methods. The recovery of a subgroup of C. Upsaliensis isolates from seeded stool specimens was also evaluated. Differences in growth of C. Upsaliensis on CAT and mCCDA were modest and were not explained by the antibiotic profiles of the two media. Recovery of C. Upsaliensis from spiked human feces on CAT was superior to that on mCCDA at lower concentrations of organisms (103 CFU/ml). We conclude that although CAT is more suitable than mCCDA for the isolation of C. Upsaliensis from stools, the superiority of CAT for detecting this organism is not accounted for by the antibiotic composition of the medium.

  • Campylobacter Upsaliensis exerts a cytolethal distending toxin effect on HeLa cells and T lymphocytes
    Microbiology, 2001
    Co-Authors: Adele Mooney, Marguerite Clyne, T. Curran, D. Doherty, B. Kilmartin, Billy Bourke
    Abstract:

    Campylobacter Upsaliensis is an emerging human enteropathogen. However, little is known about the pathogenesis of C. Upsaliensis infection. In this study the authors demonstrate that C. Upsaliensis whole-cell preparations and extracts produce a cytolethal distending toxin (CDT)-like effect on HeLa cells characterized by progressive distension and nuclear fragmentation culminating in cell death over 5 d. To further delineate the nature of this toxic effect in relation to CDT from other pathogens, the effect of C. Upsaliensis on cellular events in epithelial cells and immunocytes was investigated. C. Upsaliensis lysate-treated HeLa cells subjected to FACScan analysis using carboxyfluorescein diacetete succinimidyl ester (CFDA-SE) as a cell tracer demonstrated cell division arrest. Propidium iodide (PI) staining of HeLa cells revealed that cell cycle arrest occurred in G2/M. Human T lymphocytes exposed to C. Upsaliensis lysates also showed cell cycle arrest in G2/M. Using a combination of Annexin V/PI staining and TUNEL assay, cytodistended HeLa cells were shown to undergo apoptotic cell death. These data provide the first insights into the virulence mechanisms of this novel enteropathogen.

  • Campylobacter Upsaliensis: Waiting in the Wings
    Clinical microbiology reviews, 1998
    Co-Authors: Billy Bourke, Voon Loong Chan, Philip M. Sherman
    Abstract:

    Despite strong epidemiological evidence supporting an important role for Campylobacter Upsaliensis as a human enteropathogen, it remains relatively unknown in the realm of clinical microbiology. Clinical studies indicate that infection with this organism usually is associated with benign self-limiting diarrhea. However, more serious illnesses, including spontaneous abortion and hemolytic-uremic syndrome, recently have been associated with human infections. Understanding of the virulence properties and molecular biology of C. Upsaliensis is beginning to evolve. There is now a pressing need for controlled, prospective epidemiologic studies in addition to further in-depth investigation of the pathogenesis of this enteric Campylobacter to more precisely define its role in human disease. Furthermore, since C. Upsaliensis is sensitive to the antibiotics routinely used in Campylobacter selective media, widespread appreciation of the importance of this organism will rely on the development of widely applicable, effective techniques for its isolation.

  • Research letterPulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter Upsaliensis strains☆
    Fems Microbiology Letters, 1996
    Co-Authors: Billy Bourke, Philip M. Sherman, David L. Woodward, Hermy Lior, Voon Loong Chan
    Abstract:

    To determine the genome relatedness among a selection of animal and human Campylobacter Upsaliensis isolates, macrorestriction profiles were generated for 20 C. Upsaliensis strains, among 7 serogroups, using pulsed-field gel electrophoresis (PFGE). XhoI, SalI and SacII restriction enzyme profiles indicated genomic heterogeneity among strains. Using XhoI and SacII restriction enzyme digestion, genomic similarities between some pairs of strains were Lior serogroup specific. The genomic sizes of these isolates varied from 1.74 to 2.09 Mb. These results demonstrate molecular heterogeneity of this species similar to that found among Helicobacter pylori isolates. Among C. Upsaliensis strains, PFGE is highly discriminatory and should prove a useful molecular typing method for epidemiological purposes.

Philip M. Sherman - One of the best experts on this subject based on the ideXlab platform.

  • Invasion of human epithelial cells by Campylobacter Upsaliensis.
    Cellular microbiology, 2003
    Co-Authors: Adele Mooney, Philip M. Sherman, Catherine Byrne, Marguerite Clyne, Kathene C. Johnson-henry, Billy Bourke
    Abstract:

    Summary Few data exist on the interaction of Campylobacter Upsaliensis with host cells, and the potential for this emerging enteropathogen to invade epithelial cells has not been explored. We have characterized the ability of C. Upsaliensis to invade both cultured epi- thelial cell lines and primary human small intestinal cells. Epithelial cell lines of intestinal origin appeared to be more susceptible to invasion than non- intestinal-derived cells. Of three bacterial isolates studied, a human clinical isolate, CU1887, entered cells most efficiently. Although there was a trend towards more efficient invasion of Caco-2 cells by C. Upsaliensis CU1887 at lower initial inocula, actual numbers of intracellular organisms increased with increasing multiplicity of infection and with prolonged incubation period. Confocal microscopy revealed C. Upsaliensis within primary human small intestinal cells. Both Caco-2 and primary cells in non-confluent areas of the infected monolayers were substantially more susceptible to infection than confluent cells. The specific cytoskeletal inhibitors cytochalasin B, cytochalasin D and vinblastine attenuated invasion of Caco-2 cells in a concentration-dependent manner, providing evidence for both microtubule- and microfil- ament-dependent uptake of C. Upsaliensis . Electron microscopy revealed the presence of organisms within Caco-2 cell cytoplasmic vacuoles. C. upsalien- sis is capable of invading epithelial cells and appears to interact with host cell cytoskeletal structures in order to gain entry to the intracellular environment. Entry into cultured primary intestinal cells ex vivo provides strong support for the role of host cell inva- sion during human enteric C. Upsaliensis infection.

  • Campylobacter Upsaliensis: Waiting in the Wings
    Clinical microbiology reviews, 1998
    Co-Authors: Billy Bourke, Voon Loong Chan, Philip M. Sherman
    Abstract:

    Despite strong epidemiological evidence supporting an important role for Campylobacter Upsaliensis as a human enteropathogen, it remains relatively unknown in the realm of clinical microbiology. Clinical studies indicate that infection with this organism usually is associated with benign self-limiting diarrhea. However, more serious illnesses, including spontaneous abortion and hemolytic-uremic syndrome, recently have been associated with human infections. Understanding of the virulence properties and molecular biology of C. Upsaliensis is beginning to evolve. There is now a pressing need for controlled, prospective epidemiologic studies in addition to further in-depth investigation of the pathogenesis of this enteric Campylobacter to more precisely define its role in human disease. Furthermore, since C. Upsaliensis is sensitive to the antibiotics routinely used in Campylobacter selective media, widespread appreciation of the importance of this organism will rely on the development of widely applicable, effective techniques for its isolation.

  • Research letterPulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter Upsaliensis strains☆
    Fems Microbiology Letters, 1996
    Co-Authors: Billy Bourke, Philip M. Sherman, David L. Woodward, Hermy Lior, Voon Loong Chan
    Abstract:

    To determine the genome relatedness among a selection of animal and human Campylobacter Upsaliensis isolates, macrorestriction profiles were generated for 20 C. Upsaliensis strains, among 7 serogroups, using pulsed-field gel electrophoresis (PFGE). XhoI, SalI and SacII restriction enzyme profiles indicated genomic heterogeneity among strains. Using XhoI and SacII restriction enzyme digestion, genomic similarities between some pairs of strains were Lior serogroup specific. The genomic sizes of these isolates varied from 1.74 to 2.09 Mb. These results demonstrate molecular heterogeneity of this species similar to that found among Helicobacter pylori isolates. Among C. Upsaliensis strains, PFGE is highly discriminatory and should prove a useful molecular typing method for epidemiological purposes.

  • Pulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter Upsaliensis strains
    FEMS microbiology letters, 1996
    Co-Authors: Billy Bourke, Philip M. Sherman, David L. Woodward, Hermy Lior, Voon Loong Chan
    Abstract:

    To determine the genome relatedness among a selection of animal and human Campylobacter Upsaliensis isolates, macrorestriction profiles were generated for 20 C. Upsaliensis strains, among 7 serogroups, using pulsed-field gel electrophoresis (PFGE). XhoI, SalI and SacII restriction enzyme profiles indicated genomic heterogeneity among strains. Using XhoI and SacII restriction enzyme digestion, genomic similarities between some pairs of strains were Lior serogroup specific. The genomic sizes of these isolates varied from 1.74 to 2.09 Mb. These results demonstrate molecular heterogeneity of this species similar to that found among Helicobacter pylori isolates. Among C. Upsaliensis strains, PFGE is highly discriminatory and should prove a useful molecular typing method for epidemiological purposes.

  • Physical and genetic map of the genome of Campylobacter Upsaliensis
    Microbiology, 1995
    Co-Authors: Billy Bourke, Philip M. Sherman, Helena Louie, Eric Hani, Praveen Islur, Voon Loong Chan
    Abstract:

    Summary: A physical map of Campylobacter Upsaliensis ATCC 43954 was constructed from DNA fragments generated by SalI (5′ G/TCGAC), NarI (5′ GG/CGCC) and BssHII (5′ G/CGCGC) restriction digests separated using pulsed-field gel electrophoresis. The size of the C. Upsaliensis genome was approximately 2000 kb, providing evidence of the largest Campylobacter genome sized to date. Twenty-one fragments created from these restriction digests were assembled into a physical map using a combination of complementary methods including cross-Southern hybridization, hybridization fingerprint analysis and hybridization with homologous and heterologous (from Campylobacter jejuni) gene probes. The position of ten genetic loci, including that of the iron-uptake regulatory (fur) gene, were localized to the physical map. A genomic library of C. Upsaliensis ATCC 43954 was constructed in lambda Gem-11 vector. Fifty thousand recombinants with an average size of 16 kb represent a library about 200 times the size of the genome. Using C. jejuni DNA probes, clones representing C. Upsaliensis flaA, fur and ftsZ genes were isolated and localized to the physical map.

R De Wachter - One of the best experts on this subject based on the ideXlab platform.

  • Discrimination among thermophilic Campylobacter species by polymerase chain reaction amplification of 23S rRNA gene fragments.
    Journal of clinical microbiology, 1993
    Co-Authors: M. Eyers, Herman Goossens, Sabine Chapelle, G. Van Camp, R De Wachter
    Abstract:

    By comparing nucleic acid sequences determined for one of the most variable areas of 23S rRNA genes of 23 Campylobacter strains, we were able to identify regions specific for thermophilic Campylobacter strains. Oligonucleotide primers corresponding to these unique regions were synthesized and used in the polymerase chain reaction. One primer pair selectively detected all thermophilic Campylobacter species, while four other primer pairs allowed discrimination among the thermophilic species Campylobacter coli, Campylobacter jejuni subsp. jejuni, Campylobacter lari, and Campylobacter Upsaliensis. All primer sets were tested successfully on a large number of clinical isolates.

Voon Loong Chan - One of the best experts on this subject based on the ideXlab platform.

  • Campylobacter Upsaliensis: Waiting in the Wings
    Clinical microbiology reviews, 1998
    Co-Authors: Billy Bourke, Voon Loong Chan, Philip M. Sherman
    Abstract:

    Despite strong epidemiological evidence supporting an important role for Campylobacter Upsaliensis as a human enteropathogen, it remains relatively unknown in the realm of clinical microbiology. Clinical studies indicate that infection with this organism usually is associated with benign self-limiting diarrhea. However, more serious illnesses, including spontaneous abortion and hemolytic-uremic syndrome, recently have been associated with human infections. Understanding of the virulence properties and molecular biology of C. Upsaliensis is beginning to evolve. There is now a pressing need for controlled, prospective epidemiologic studies in addition to further in-depth investigation of the pathogenesis of this enteric Campylobacter to more precisely define its role in human disease. Furthermore, since C. Upsaliensis is sensitive to the antibiotics routinely used in Campylobacter selective media, widespread appreciation of the importance of this organism will rely on the development of widely applicable, effective techniques for its isolation.

  • Research letterPulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter Upsaliensis strains☆
    Fems Microbiology Letters, 1996
    Co-Authors: Billy Bourke, Philip M. Sherman, David L. Woodward, Hermy Lior, Voon Loong Chan
    Abstract:

    To determine the genome relatedness among a selection of animal and human Campylobacter Upsaliensis isolates, macrorestriction profiles were generated for 20 C. Upsaliensis strains, among 7 serogroups, using pulsed-field gel electrophoresis (PFGE). XhoI, SalI and SacII restriction enzyme profiles indicated genomic heterogeneity among strains. Using XhoI and SacII restriction enzyme digestion, genomic similarities between some pairs of strains were Lior serogroup specific. The genomic sizes of these isolates varied from 1.74 to 2.09 Mb. These results demonstrate molecular heterogeneity of this species similar to that found among Helicobacter pylori isolates. Among C. Upsaliensis strains, PFGE is highly discriminatory and should prove a useful molecular typing method for epidemiological purposes.

  • Pulsed-field gel electrophoresis indicates genotypic heterogeneity among Campylobacter Upsaliensis strains
    FEMS microbiology letters, 1996
    Co-Authors: Billy Bourke, Philip M. Sherman, David L. Woodward, Hermy Lior, Voon Loong Chan
    Abstract:

    To determine the genome relatedness among a selection of animal and human Campylobacter Upsaliensis isolates, macrorestriction profiles were generated for 20 C. Upsaliensis strains, among 7 serogroups, using pulsed-field gel electrophoresis (PFGE). XhoI, SalI and SacII restriction enzyme profiles indicated genomic heterogeneity among strains. Using XhoI and SacII restriction enzyme digestion, genomic similarities between some pairs of strains were Lior serogroup specific. The genomic sizes of these isolates varied from 1.74 to 2.09 Mb. These results demonstrate molecular heterogeneity of this species similar to that found among Helicobacter pylori isolates. Among C. Upsaliensis strains, PFGE is highly discriminatory and should prove a useful molecular typing method for epidemiological purposes.

  • Physical and genetic map of the genome of Campylobacter Upsaliensis
    Microbiology, 1995
    Co-Authors: Billy Bourke, Philip M. Sherman, Helena Louie, Eric Hani, Praveen Islur, Voon Loong Chan
    Abstract:

    Summary: A physical map of Campylobacter Upsaliensis ATCC 43954 was constructed from DNA fragments generated by SalI (5′ G/TCGAC), NarI (5′ GG/CGCC) and BssHII (5′ G/CGCGC) restriction digests separated using pulsed-field gel electrophoresis. The size of the C. Upsaliensis genome was approximately 2000 kb, providing evidence of the largest Campylobacter genome sized to date. Twenty-one fragments created from these restriction digests were assembled into a physical map using a combination of complementary methods including cross-Southern hybridization, hybridization fingerprint analysis and hybridization with homologous and heterologous (from Campylobacter jejuni) gene probes. The position of ten genetic loci, including that of the iron-uptake regulatory (fur) gene, were localized to the physical map. A genomic library of C. Upsaliensis ATCC 43954 was constructed in lambda Gem-11 vector. Fifty thousand recombinants with an average size of 16 kb represent a library about 200 times the size of the genome. Using C. jejuni DNA probes, clones representing C. Upsaliensis flaA, fur and ftsZ genes were isolated and localized to the physical map.

M. D. Salihu - One of the best experts on this subject based on the ideXlab platform.

  • Survey of thermophilic Campylobacter species in cats and dogs in north-western Nigeria.
    Veterinaria italiana, 2010
    Co-Authors: M. D. Salihu, A. A. Magaji, Junaidu U Abdulkadir, Adewale Kolawale
    Abstract:

    This study was conducted in north-western Nigeria to investigate the role of cats and dogs as potential reservoirs of thermophilic Campylobacter species. Faecal samples were analysed from 104 cats and 141 dogs between March 2007 and March 2009. The samples were collected from animals in households, those presented to veterinary premises and feline colonies. Campylobacter spp. were isolated from 39 (27.7%) and 19 (18.3%) dogs and cats, respectively. There was no significant difference in isolation rate observed between dogs (27.7%) and cats (18.3%) and there was also no significance difference between younger and older dogs; 23.1% (young) compared to 30.3% (older) dogs, but a significant difference was seen between young (4.3%) and older (29.3%) cats. Campylobacter Upsaliensis predominated in the isolates, accounting for 89.5% and 74.4% of the positive samples in cats and dogs, respectively, C. jejuni constituted 21.1% and 23.1% of the positive samples from cats and dogs, respectively. This finding is an indication that dogs and cats frequently shed thermophilic Campylobacter spp. which could be of public health importance. To establish the zoonotic significance of canine and feline Campylobacter, isolates need to be further characterised and compared. This is the first study on the prevalence of Campylobacter in cats and dogs in the region.

  • Prevalence of Campylobacter species in apparently healthy goats in Sokoto state (Northwestern) Nigeria
    African Journal of Microbiology Research, 2009
    Co-Authors: M. D. Salihu, A. U. Junaidu, S. I. Oboegbulem, G. O. Egwu, F. M. Tambuwal, Yusuf Yakubu
    Abstract:

    A total of 1312 rectal swabs (feacal) samples were collected from apparently healthy goats across Sokoto state and processed for Campylobacter organisms. 264 (20.1%) of the samples were positive and yielded 272 Campylobacter species.Campylobacter species isolated in this study were Campylobacter jejuni 169(62.1%),Campylobacter coli 58(21.3%), Campylobacter lari 24(8.8%), Campylobacter Upsaliensis 13(4.8%) and Campylobacter sputorum 8(3.0%). Biotyping of the isolates indicated that C. jejuni biotype I (52.6%) and C. coli biotype II (82.8%) were the most common biotypes while all the C. lari isolates were biotype I. The isolation of Campylobacter organisms and the identification of C. jejuni biotype I and C. colibiotype II from goats in this study is a clear indication of the presence ofCampylobacter in goats in Sokoto state. Campylobacter organisms must be considered as potential agent of enteritis and abortion in goats as well as a serious public health problem.   Key words: Biotypes, Campylobacter, Campylobacter jejuni, Campylobacter coli,Nigeria, prevalence, goats.

  • Prevalence and Biotypes of Campylobacter Species Isolated from Sheep in Sokoto State, Nigeria
    2009
    Co-Authors: M. D. Salihu, A. U. Junaidu, S. I. Oboegbulem, G. O. Egwu
    Abstract:

    Rectal sw abs (feacal) samples were collected from 518 sheep across Sokoto state and processed for Campylobacter organisms. Of a total of 518 samples, 93(18.0%) yielded Campylobacter organisms. The Campylobacter species isolated in this study were Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter Upsaliensis. The most frequently isolated Campylobacter species was C. jejuni (79.6%), while C. Upsaliensis had the lowest isolation rate of 2.2%. Biotyping of the isolates indicated that C. jejuni biotype I (44.6%) and C. coli biotype I (72.7%) were the most common biotypes while all the C. lari isolates were biotype II. The isolation of Campylobacter organisms and the identification of C. jejuni biotype I and C. coli biotype I from sheep in this study is a clear indication of the presence of Campylobacter in sheep in Sokoto state. Campylobacter organisms must be considered as potential agent of ovine enteritis and abortion as well as a serious public health problem.

  • healthy goats in Sokoto state (Northwestern) Nigeria
    2009
    Co-Authors: Short Communication, M. D. Salihu, A. U. Junaidu, S. I. Oboegbulem, G. O. Egwu, F. M. Tambuwal
    Abstract:

    A total of 1312 rectal swabs (feacal) samples were collected from apparently healthy goats across Sokoto state and processed for Campylobacter organisms. 264 (20.1%) of the samples were positive and yielded 272 Campylobacter species. Campylobacter species isolated in this study were Campylobacter jejuni 169(62.1%), Campylobacter coli 58(21.3%), Campylobacter lari 24(8.8%), Campylobacter Upsaliensis 13(4.8%) and Campylobacter sputorum 8(3.0%). Biotyping of the isolates indicated that C. jejuni biotype I (52.6%) and C. coli biotype II (82.8%) were the most common biotypes while all the C. lari isolates were biotype I. The isolation of Campylobacter organisms and the identification of C. jejuni biotype I and C. coli biotype II from goats in this study is a clear indication of the presence of Campylobacter in goats in Sokoto state. Campylobacter organisms must be considered as potential agent of enteritis and abortion in goats as well as a serious public health problem