Clinical and molecular characterisation of Vibrio furnissii isolates from patients with diarrhoea

Abstract

Background: Vibrio furnissii is an emerging human pathogen closely related to Vibrio fluvialis that causes acute gastroenteritis. However, the distribution of virulence factors, antibiotic resistance and molecular epidemiological features of V. furnissii isolates in China remain unknown. Results: We collected seven V. furnissii strains from 1,985 stool samples from people over 14 years old with acute diarrhoea at a general hospital in Beijing, China between April and October 2018. Blood agar plates with 20 μg/mL ampicillin helped to isolate more V. furnissii compared with only using TCBS ( thiosulfate-citrate-bile salts-sucrose agar). Phylogenetic analysis based on SNPs (single-nucleotide polymorphisms) was used to assess the relatedness of isolates. Virulence genes T2SS, T3SS, vfh, hupO and vfp were detected in all V. furnissii strains, and T6SS also occurred at a high frequency of 85.7%. High resistance to cefazolin and tetracycline was found in the V. furnissii isolates at respective rates of 100.0% and 57.1%, and intermediate resistance to ampicillin/sulbactam and imipenem was found at respective rates of 85.7% and 85.7%. Of the tested strains, 42.9% showed resistance to at least three antibiotics. Transposon islands with concentrations of resistance genes occurred in two strains. Phylogenetic analysis separated the V. furnissii strains into three major clades. Conclusion: This study provided detailed bioinformatic, antibiotic susceptibility and clinical features of V. furnissii in China. However, continued and enhanced laboratory-based surveillance is needed for prevention and control of V. furnissii infection.