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Comparative Genomic Analysis of Clinical Strains of Campylobacter jejuni from South Africa

ABSTRACT: Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-BarrÃ© and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-BarrÃ© or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. The genomic diversity of 33 South African, 2 Mexican and 1 Canadian Campylobacter jejuni strains from humans were examined by microarray-based comparative genomic indexing (CGI) analysis. The CGI analysis allowed the assessment of CDS content for each C. jejuni strain relative to the C. jejuni DNA microarray, which comprises ORFs from strains NCTC 11168, RM1221. ORFs were spotted in duplicate. Genomic DNA from strains NCTC 11168/RM1221 were used as a reference DNA and competitively hybridized with genomic DNA from each of the other C. jejuni strains. Two or three replicates for each strain were performed. Data normalization was performed as in Parker et al. J Clin Microbiol 2006, 44(11):4125-4135.

ORGANISM(S): Campylobacter jejuni

SUBMITTER: Craig Parker

PROVIDER: E-GEOD-9862 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Comparative genomic analysis of clinical strains of Campylobacter jejuni from South Africa.

Quiñones Beatriz B Guilhabert Magalie R MR Miller William G WG Mandrell Robert E RE Lastovica Albert J AJ Parker Craig T CT

PloS one 20080423 4

<h4>Background</h4>Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the post-infectious neuropathies, Guillain-Barré and Miller Fisher syndromes. In the Cape Town area of South Africa, C. jejuni strains with Penner heat-stable (HS) serotype HS:41 have been observed to be overrepresented among cases of Guillain-Barré syndrome. The present study examined the genetic content of a collection of 32 South African C. jejuni strains with different serotypes, in ...[more]

PMID: 18431496

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Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. Keywords: comparative genomic indexing analysis

Project description:C. jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human foodborne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion as evidenced by gentamicin-protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC demonstrated Cia secretion as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene as judged by B-galactosidase reporter assays and real-time RT-PCR. Microarray analysis revealed that DOC induced the expression of virulence genes (i.e., ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrate that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation to identify genes expressed by C. jejuni in response to in vivo-like culture conditions. Keywords: Stress response For the expression profiling arrays, an indirect comparison of gene expression was performed, where the expression profile of the C. jejuni F38011 cultured in the presence and absence of DOC was measured separately on different slides as described previously (26). Briefly, Cy5 labeled reference DNA from the C. jejuni F38011 strain was mixed with Cy3 labeled test cDNA (C. jejuni F38011 cultured in the presence or absence of DOC) and hybridized to the Campylobacter cDNA array (26) on separate slides. DNA microarrays were scanned using an Axon GenePix 4000B microarray laser scanner (Axon Instruments, Union City, CA) and the data for spot and background intensities were processed using the GenePix 4.0 software. To compensate for any effect of the amount of template and uneven Cy-dye incorporation, data normalization was performed as previously described (26). For the comparison of genes differentially expressed in the presence and absence of DOC,six hybridization measurements were generated per biological experiment (three technical replicate arrays and two replicate features per array).

Dataset Information

Comparative Genomic Analysis of Clinical Strains of Campylobacter jejuni from South Africa

Publications

Comparative genomic analysis of clinical strains of Campylobacter jejuni from South Africa.

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