Distribution, Antibiotic Resistance, and Virulence Factors of in the Southern Coastal Waters of Republic of Korea.

is a marine bacterium and a major cause of food poisoning worldwide, primarily associated with gastric illnesses such as gastroenteritis. This study aimed to investigate the distribution, antibiotic resistance, and virulence genes of present in shellfish and seawater of the southern coast of Korea, a major shellfish harvesting area. Shellfish and seawater samples were collected monthly in 2023 from 24 coastal sites in Korea. was isolated and identified using the MPN method, biochemical tests, MALDI-TOF mass spectrometry, and 16S rRNA sequencing. Antimicrobial susceptibility was tested for 673 isolates using the Sensititre MIC system, and virulence genes ( and ) were detected by PCR. had a detection rate of 18.2-58.3% in shellfish and 8.3-50% in seawater samples. Among the isolates, 97.9% and 97.3% were resistant to ampicillin and colistin, respectively, while 8.3% showed resistance to four or more antibiotics. The virulence genes and were detected in 0.45% and 3.34% of shellfish samples and 1.23% and 4.46% of seawater samples, respectively. These findings will help implement appropriate precautionary measures to prevent potential human health risks arising from exposure to multidrug-resistant or pathogenic .