Genetic characteristics and potential pathogenic agents in Campylobacter upsaliensis based on genomic analysis

ABSTRACT

Campylobacter upsaliensis was the most common Campylobacter species in pets’ gastrointestinal tracts and has been isolated from patients with bacteremia, hemolytic-uremic syndrome, spontaneous abortion, and Guillain-Barré syndrome. However, the genetic characteristics and the full extent of its significance as a human pathogen remain to be fully understood. This study involved an investigation for genomic analysis of 154 strains from different sources and additional antimicrobial resistance profiles of 26 strains for this species. The genomes contained 1,558–1,971 CDS and the genome sizes were estimated to vary from 1.53 Mb to 1.86 Mb, with an average GC content of  34.71%. The entire analyzed genomes could be divided into three clades (A, B, and C) based on ANI and phylogenomic analysis. Significantly, nearly all strains in Clade B were isolated from patient samples, and the virulence-related sequences FlgD, GmhA, and CdtC might serve as determining factors for the classification of Clade B. Half of the tested isolates had MIC values over 64 μg mL⁻¹ for nalidixic acid, gentamicin, and streptomycin. Isolates from pets in China carried more resistant elements in the genomes. This study both provided a comprehensive profile of C. upsaliensis for its genomic features and suggested some pathogenic agents for human infection with this species.

KEYWORDS:

• Campylobacter upsaliensis
• pathogenic agent
• comparative genomics
• virulence factor
• antimicrobial resistance

Acknowledgments

We extend our gratitude to Academician George Fu Gao, Chinese Academy of Sciences, for his invaluable support for the project formulation and sample collections. We thank Dr. Lang Liu from the New Ruipeng Pet Healthcare Group for his kind help with the pet’s sample collections. We also should thank our colleagues from Nanshan Centre for Disease Control and Prevention, and Shunyi District Centre for Disease Control and Prevention.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Sponsored by the National Key Research and Development Program of China [grant no 2021YFC2301000], the Campylobacter standard strains applied to “National standards for food safety” [grant no TS202302], the Project for Research on detection and tracing of important pathogen combinations, identification and prevention of drug resistance hazards (29140) and Project for Gonorrhea vaccine development (33076).