|Miller, William - Bill|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/28/2009
Publication Date: 7/1/2009
Citation: Habib, I., Louwen, R., Uytendaele, M., Houf, K., Vandenberg, O., Nieuwenhuis, E.E., Miller, W.G., Vanbelkum, A., Dezutter, L. 2009. Correlation between genotypic diversity, lipooligosaccharide gene locus class variation and Caco-2 invasion potential of Campylobacter jejuni from human and chicken meat origin: a contribution to virulotyping. Applied and Environmental Microbiology. 75(13):4277-4288. Interpretive Summary: The outer surface of the human pathogen Campylobacter jejuni plays a role in both evasion of the human immune response and, in some cases, in the development of post-infection paralytic disorders. The outer surface of C. jejuni can be classified into one of several groups, based on the sugars present in the LOS layer. Some C. jejuni outer surface structures mimic sugar-containing surface structures present on human nerve cells. Thus, an immune response to these sugars after infection with C. jejuni triggers also an immune response against human nerve cells, leading to paralytic disease. Therefore, the LOS class of the C. jejuni cell can be important clinically. This study screened human clinical C. jejuni isolates and C. jejuni isolates from chicken meat for the presence of certain LOS classes. LOS classes associated with paralytic disease were found on chicken meat isolates; these isolates also invaded human cells at a higher level that isolates not associated with paralytic disorders. Finally, multi-locus sequence typing analysis showed a correlation between sequence type and LOS class. Therefore, a simple screening method could be used to determine the presence of more clinically relevant Campylobacters.
Technical Abstract: Significant interest in studying the lipooligosaccharide (LOS) of Campylobacter jejuni stemmed from its potential role in post-infection paralytic disorders. In this study we present PCR screening of five LOS locus classes (A, B, C, D, and E), for a collection of 117 C. jejuni strains from chicken meat and sporadic human cases with diarrhoea. We correlated LOS classes and clonal complexes as assigned by multilocus sequence typing (MLST). Finally, we evaluated the invasion potential of a panel of 36 C. jejuni strains in Caco-2 cells. PCR screening showed that 87.2% (102/117) of strains 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 strains grouped in CC-21 shown to express LOS locus class C. Invasion potential of C. jejuni strains possessing sialylated LOS (n=23; classes A, B, and C) was significantly higher (P value= 0.002) than C. jejuni strains with non-sialylated LOS (n=13; classes D and E). There was no significant difference between chicken meat and human isolates regarding their invasiveness. However, C. jejuni strains in CC-206 (correlated with LOS class B) provided a statistically- significant higher invasion level, while invasiveness of C. jejuni strains in CC-45 (correlated with LOS class E) was lowest. Correlation between LOS classes and CCs was further confirmed by Pulsed Field Gel Electrophoresis. The present study reveals a correlation between genotypic diversity and LOS locus classes of C. jejuni. We showed that simple PCR screening for LOS classes could reliably predict certain MLST CCs in C. jejuni. 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 be an adaptive mechanism by C. jejuni in order to better survive in a host.