AUTHOR=Xu Xiaomin , Liang Shanyan , Li Xin , Hu Wenjin , Li Xi , Lei Liusheng , Lin Huai 

TITLE=Antibiotic resistance and virulence characteristics of Vibrio vulnificus isolated from Ningbo, China

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1459466

DOI=10.3389/fmicb.2024.1459466

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p><italic>Vibrio vulnificus</italic> (<italic>V. vulnificus</italic>) is a deadly opportunistic human pathogen with high mortality worldwide. Notably, climate warming is likely to expand its geographical range and increase the infection risk for individuals in coastal regions. However, due to the absence of comprehensive surveillance systems, the emergence and characteristics of clinical <italic>V. vulnificus</italic> isolates remain poorly understood in China.</p></sec><sec><title>Methods</title><p>In this study, we investigate antibiotic resistance, virulence including serum resistance, and hemolytic ability, as well as molecular characteristics of 21 <italic>V. vulnificus</italic> isolates collected from patients in Ningbo, China.</p></sec><sec><title>Results and discussion</title><p>The results indicate that all isolates have been identified as potential virulent <italic>vcg</italic> C type, with the majority (16 of 21) classified as <italic>16S rRNA</italic> B type. Furthermore, these isolates exhibit a high level of antibiotic resistance, with 66.7% resistance to more than three antibiotics and 61.9% possessing a multiple antibiotic resistance (MAR) index exceeding 0.2. In terms of virulence, most isolates were categorized as grade 1 in serum resistance, with one strain, S12, demonstrating intermediate sensitivity in serum resistance, belonging to grade 3. Whole genome analysis disclosed the profiles of antibiotic resistance genes (ARGs) and virulence factors (VFs) in these strains. The strains share substantial VF genes associated with adherence, iron uptake, antiphagocytosis, toxin, and motility. In particular, key VFs such as capsule (CPS), lipopolysaccharide (LPS), and multifunctional autoprocessing repeats-in-toxin (MARTX) are prevalent in all isolates. Specifically, S12 possesses a notably high number of VF genes (672), which potentially explains its higher virulence. Additionally, these strains shared six ARGs, namely, <italic>PBP3</italic>, <italic>adeF</italic>, var<italic>G</italic>, <italic>parE</italic>, and <italic>CRP</italic>, which likely determine their antibiotic resistance phenotype.</p></sec><sec><title>Conclusion</title><p>Overall, our study provides valuable baseline information for clinical tracking, prevention, control, and treatment of <italic>V. vulnificus</italic> infections.</p></sec>