AUTHOR=Fleischmann Susanne , Herrig Ilona , Wesp Jessica , Stiedl Joscha , Reifferscheid Georg , Strauch Eckhard , Alter Thomas , Brennholt Nicole 

TITLE=Prevalence and Distribution of Potentially Human Pathogenic Vibrio spp. on German North and Baltic Sea Coasts

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.846819

DOI=10.3389/fcimb.2022.846819

ISSN=2235-2988

ABSTRACT=<p>Global ocean warming results in an increase of infectious diseases including an elevated emergence of <italic>Vibrio</italic> spp. in Northern Europe. The European Centre for Disease Prevention and Control reported annual periods of high to very high risks of infection with <italic>Vibrio</italic> spp. during summer months along the North Sea and Baltic Sea coasts. Based on those facts, the risk of <italic>Vibrio</italic> infections associated with recreational bathing in European coastal waters increases. To obtain an overview of the seasonal and spatial distribution of potentially human pathogenic <italic>Vibrio</italic> spp. at German coasts, this study monitored <italic>V. cholerae</italic>, <italic>V. parahaemolyticus</italic>, and <italic>V. vulnificus</italic> at seven recreational bathing areas from 2017 to 2018, including the heat wave event in summer 2018. The study shows that all three <italic>Vibrio</italic> species occurred in water and sediment samples at all sampling sites. Temperature was shown to be the main driving factor of <italic>Vibrio</italic> abundance, whereas <italic>Vibrio</italic> community composition was mainly modulated by salinity. A species-specific rapid increase was observed at water temperatures above 10°C, reaching the highest detection numbers during the heat wave event with abundances of 4.5 log10 CFU+1/100 ml of seawater and 6.5 log10 CFU+1/100 g of sediment. Due to salinity, the dominant <italic>Vibrio</italic> species found in North Sea samples was <italic>V. parahaemolyticus</italic>, whereas <italic>V. vulnificus</italic> was predominantly detected in Baltic Sea samples. Most detections of <italic>V. cholerae</italic> were associated with estuarine samples from both seas. <italic>Vibrio</italic> spp. concentrations in sediments were up to three log higher compared to water samples, indicating that sediments are an important habitat for <italic>Vibrio</italic> spp. to persist in the environment. Antibiotic resistances were found against beta-lactam antibiotics (ampicillin 31%, cefazolin 36%, and oxacillin and penicillin 100%) and trimethoprim-sulfamethoxazole (45%). Moreover, isolates harboring pathogenicity-associated genes such as <italic>trh</italic> for <italic>V. parahaemolyticus</italic> as well as <italic>vcg</italic>, <italic>cap</italic>/<italic>wcv</italic>, and the 16S rRNA-type B variant for <italic>V. vulnificus</italic> were detected. All sampled <italic>V. cholerae</italic> isolates were identified as non-toxigenic non-O1/non-O139 serotypes. To sum up, increasing water temperatures at German North Sea and Baltic Sea coasts provoke elevated <italic>Vibrio</italic> numbers and encourage human recreational water activities, resulting in increased exposure rates. Owing to a moderate Baltic Sea salinity, the risk of <italic>V. vulnificus</italic> infections is of particular concern.</p>