Antibiotic Resistance and Epidemiology of Vibrio parahaemolyticus from Clinical Samples in Nantong, China, 2018-2021

Purpose: The objective of this study was to investigate the prevalence and molecular characteristics of Vibrio parahaemolyticus isolates from fecal samples of patients in Nantong, China. Methods: From 2018 to 2021, a total of 106 clinical cases and samples of V. parahaemolyticus infection were collected. The virulence genes, serotypes and antibiotic resistance of these isolates were analyzed. Additionally, pulsed-field gel electrophoresis (PFGE) was used to analyze the homogeneity of the isolates. Results: Outbreaks of V. parahaemolyticus infection were concentrated in the summer, with seafood consumption being the primary contributing factor, followed by meat and meat products. tlh+tdh+trh-was confirmed as the most frequently detected virulence genotype among the clinical isolates. 16 serotypes were identified, and O3:K6 was the dominant serotype in Nantong. The antimicrobial susceptibility testing revealed the highest resistance rate to cefazolin (99.1%, 104/106), followed by ampicillin (64.2%, 68/106) and tetracycline (29.2%, 31/106). Fourteen resistant phenotypes were identified, with ampicillin-cefazolin being the most prevalent. The multiple antibiotic resistance (MAR) index ranged from 0.07 to 0.36. PFGE typing clustered isolates with similarity greater than 85% into ten genetic clusters (A-J). Conclusion: Clinical isolates generally exhibited pathogenicity and drug resistance, with some isolates displaying high homology. Clusters C, E, and G were the predominant circulating clusters in this area, posing a potential risk of recurrent outbreaks, which demanded our vigilance.

Automated summary

This study investigated the prevalence and molecular characteristics of Vibrio parahaemolyticus isolates from fecal samples of patients in Nantong, China. The results showed that outbreaks of this infection were concentrated in the summer, with seafood consumption being the primary contributing factor. The clinical isolates exhibited pathogenicity and drug resistance, with some isolates displaying high homology.