Genetic Characteristics of Lipooligosaccharide and Capsular Polysaccharide of Campylobacter jejuni from Different Sources in China.

Objective:To determine the distribution of two important virulence factors [lipooligosaccharide (LOS) and capsular polysaccharide (CPS)] in Campylobacter jejuni ( C. jejuni) isolated from different sources in China and to develop a rapid screening method for Guillain-Barré syndrome (GBS)-associated strains. Methods:Whole-genome sequencing was carried out for 494 C. jejuni strains. The OrthoMCL software was used to define the LOS/CPS gene clusters. CPS genotyping was performed with serotype-specific sequence alignment using the BLAST software. Real-time Polymerase chain reaction (PCR) was developed with the unique sequences of specific CPS types. Results:Nine novel and 29 previously confirmed LOS classes were identified. LOS classes A, B, and C were the most common (48.2%, 238/494) among the 494 strains. Twenty-six capsular types were identified in 448 strains. HS2, HS4c, HS5/31, HS19, and HS8/17 were the most frequent CPS genotypes (58.7%, 263/448). Strains of 17 CPS genotypes (strain number > 5) had one or two prevalent LOS classes ( P < 0.05). Multiplex real-time PCR for rapid identification of HS2, HS19, and HS41 was developed and validated with strains of known serotypes. Conclusion:Our results describe the genetic characteristics of the important virulence factors in C. jejuni strains in China. The multiplex real-time PCR developed in this study will facilitate enhanced surveillance of GBS-associated strains in China.