ARS | Publication request: The Complete Genome of the Human Clinical Isolate Campylobacter upsaliensis RM3195

Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: September 2, 2009
Publication Date: N/A

Interpretive Summary: Campylobacter jejuni is a leading cause of bacterial food-borne illness worldwide. Although C. jejuni can be transmitted through milk, water and a wide variety of foods, the primary route of transmission is via poultry consumption, mainly chicken. Campylobacter jejuni strains are classified by serotype; some serotypes are strongly associated with the autoimmune disease Guillain-Barre syndrome (GBS). In this study, chicken meat C. jejuni isolates were classified by serotype and sequence group. Some sequence groups were correlated strongly with serotype and some sequence groups showed a significantly higher invasion potential in human epithelial cells. However, isolates from chicken meat and human clinical isolates did not differ in invasion potential. The invasion potential of GBS isolates was higher than the invasion potential of non-GBS isolates.

Technical Abstract: INTRODUCTION: Significant interest in studying the lipooligosaccharide (LOS) of Campylobacter jejuni stemmed from its potential role in post-infection paralytic disorders. METHODS: In this study we present PCR screening of five LOS locus classes (A, B, C, D, and E), for a collection of 116 C. jejuni isolates from chicken meat (n= 76) and sporadic human cases with diarrhoea (n= 40). We correlated LOS classes with clonal complexes as assigned by multilocus sequence typing (MLST). Finally, we evaluated the invasion potential of a panel of 52 C. jejuni strains in Caco-2 cells. RESULTS: PCR screening showed that 87.1% (101/116) of isolates could be assigned to LOS classes A, B, C, D or E. Concordance between LOS classes and certain MLST clonal complexes (CC) was revealed. The majority (85.7% (24/28)) of C. jejuni isolates grouped in CC-21 were shown to express LOS locus class C. Caco-2 cells invasion potential of C. jejuni isolates possessing sialylated LOS (n=29; classes A, B, and C) was significantly higher (P value < 0.0001) than C. jejuni isolates with non-sialylated LOS (n=23; classes D and E). There was no significant difference between chicken meat and human isolates regarding their invasiveness. However, C. jejuni assigned to CC-206 (correlated with LOS class B) and CC-21 (correlated with LOS class C) showed a statistically significant higher invasion. Correlation between LOS classes and CCs was further confirmed by pulsed-field gel electrophoresis. CONCLUSION: The present study reveals a correlation between genotypic diversity and LOS locus classes of C. jejuni. We showed that simple PCR screening for C. jejuni LOS classes could reliably predict certain MLST CCs and adds further insight to molecular typing result. Our study corroborates that sialylation of LOS could be advantageous for C. jejuni fitness and virulence in different hosts. Modulation of cell-surface carbohydrate structure could allow C. jejuni to better adapt to or survive in a host.