Genomic Diversity inCampylobacter jejuni: Identification ofC. jejuni81-176-Specific Genes

Abstract

Since the publication of the complete genomic sequence of Campylobacter jejuni NCTC 11168 in February 2000, evidence has been compiling that suggests C. jejuni strains exhibit high genomic diversity. In order to investigate this diversity, the unique genomic DNA sequences from a nonsequenced Campylobacter strain, C. jejuni 81-176, were identified by comparison with C. jejuni NCTC 11168 by using a shotgun DNA microarray approach. Up to 63 kb of new chromosomal DNA sequences unique to this pathogen were obtained. Eighty-six open reading frames were identified by the presence of uninterrupted coding regions encoding a minimum of 40 amino acids. In addition, this study shows that the whole-plasmid shotgun microarray approach is effective and provides a comprehensive coverage of DNA regions that differ between two closely related genomes. The two plasmids harbored by this Campylobacter strain, pTet and pVir, were also sequenced, with coverages of 2.5-and 2.9-fold, respectively, representing 72 and 92% of their complete nucleotide sequences. The unique chromosomal genes encode proteins involved in capsule and lipooligosaccharide biosynthesis, restriction and modification systems, and respiratory metabolism. Several of these unique genes are likely associated with C. jejuni 81-176 fitness and virulence. Interestingly, the comparison of C. jejuni 81-176 unique genes with those of C. jejuni ATCC 43431 revealed a single gene which encodes a probable TraG-like protein. The product of this gene might be associated with the mechanism of C. jejuni invasion into epithelial cells. In conclusion, this study extends the repertoire of C. jejuni genes and thus will permit the construction of a composite and more comprehensive microarray of C. jejuni.

Detection of Campylobacter species in stool specimens from patients with symptoms of acute flaccid paralysis in South Africa

“…Given that gastroenteritis due to C. jejuni infections are hyperendemic among young children (< 5 years) in tropical resource-poor settings, it is expected that the prevalence of C. jejuni-induced GBS would be prevalent among individuals of < 5 years of age. Other researchers, using a broader case definition that includes all age groups for GBS surveillance, have published reports of bimodal distribution of GBS cases by age, with more cases identified in young adults (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and the elderly (significantly higher) [4,16,29,30].…”

“…The Penner heat-stable (HS) serotypes of C. jejuni strains that are attributed to GBS include serotype HS:19 which has been reported to occur globally; and serotype HS:41 which reportedly is restricted to Cape Town, South Africa [8,11,12,[18][19][20]. During a five year study period (January 2005 to December 2009) a total of 1 501 AFP cases were reported in South Africa, of which 67.2% (1009/1501) were children aged < 5 years of age and 54.3% (815/1501) were male [21].…”

Multigenome analysis identifies a worldwide distributed epidemic Legionella pneumophila clone that emerged within a highly diverse species

“…Similar comparative genomic hybridization studies on Campylobacter jejuni (Dorrell et al 2001) and V. cholerae (Dziejman et al 2005) identified strain specificities in RM systems. The presence of genes encoding type-I RM systems correlated with different gastric responses of the host to Helicobacter pylori (Bjorkholm et al 2002), and it is thought to modulate the virulence potential of Campylobacter strains (Poly et al 2005). The identification of a worldwide distributed L. pneumophila strain, resembling strain Paris, now opens exciting possibilities of research to find out whether the specific genes contribute to improved interaction with the host or to improved fitness in the environment.…”

Genome Sequence of a Clinical Isolate of Campylobacter jejuni from Thailand

“…This suggests that genes necessary for induction of inflammatory diarrhea are among the genes shared by 81-176 and GC8486 and that the reasons for the higher level of in vitro invasion by 81-176 remain obscure (17). Collectively, multiple genome data indicate that the major genetic differences among C. jejuni strains are in the three carbohydrate loci (10,17,31,33,34), and it may be that differences in these surface antigens affect virulence both in vivo and in vitro. However, the possibility that more subtle changes in the nucleotide sequences of genes common to Campylobacter strains may also modulate pathogenesis cannot be ruled out.…”

“…The publication of the genome of a clinical isolate of C. jejuni from the United Kingdom, NCTC 11168 (31), elucidated much about the biology of this bacterium but revealed no novel virulence factors that it has in common with other bacteria other than a previously unrecognized capsular polysaccharide (31). Whole-genome microarrays have been used extensively to explore the genomic diversity of C. jejuni (9,21,22,30,(32)(33)(34)38), and recently the complete genomes of a second C. jejuni strain, RM1221, which was isolated from chicken skin but whose virulence properties are unknown, and strains of Campylobacter coli, Campylobacter lari, and Campylobacter upsaliensis have been published (10). Ten additional strains of Campylobacter spp.…”