Rapid Proliferation of Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae during Freshwater Flash Floods in French Mediterranean Coastal Lagoons

Abstract

Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae are Gram-negative halophilic bacteria autochthonous to marine and estuarine environments and components of those ecosystems (1). These vibrios are recognized throughout the world as agents of gastroenteritis resulting from consumption of raw or undercooked seafood and serious infections caused by exposure of skin wounds to seawater (2).Subpopulations of V. parahaemolyticus and V. vulnificus are potential agents of disease outbreaks. For example, enteropathogenic strains of V. parahaemolyticus produce a thermostable direct hemolysin (TDH) and/or a TDH-related hemolysin (TRH), and the genes tdh and trh code for TDH and TRH, respectively (3). Other factors are associated with virulence of V. vulnificus, including the vvhA gene encoding hemolytic cytolysin (4, 5). It is important to note that V. parahaemolyticus is the leading cause of bacterial human gastroenteritis associated with seafood consumption, especially in the United States and Japan (6,7,8). In the United States, V. vulnificus is responsible for 95% of all seafoodrelated deaths, with a mortality rate of around 50% (5). V. cholerae, the etiologic agent of cholera, has been detected in natural freshwater and brackish water worldwide, even in areas where no clinical cases of cholera have been reported (1). Most environmental isolates of V. cholerae are of the non-O1/non-O139 serotype but are capable of causing diarrheal outbreaks (7, 9). The presence and isolation of these three Vibrio spp. have also been documented to occur in coastal waters and shellfish-rearing areas in Europe, i.e., Spain (10), Italy (11, 12), Denmark (13), and Norway (14). These vibrios have been isolated in French coastal waters and shellfish at different locations along the English Channel, the Atlantic Ocean, and the Mediterranean Sea (15,16,17,18).Vibrios are less frequently associated with outbreaks of disease in Europe than in the United States and Asia, and specifically, the risk of V. parahaemolyticus infection is considered to be low (8,19). In France, 100 cases of V. parahaemolyticus infection were reported in 2001, following consumption of mussels imported from Ireland (20). Since then, only sporadic cases of Vibrio infections have been described (21,22).From the perspective of vibrio ecology, the spatiotemporal distribution of vibrios has been linked to environmental factors, with temperature being one of the most important, because it is related to seasonal distribution in temperate coastal areas, with maximal abundance during summer through early fall (23,24,25,26,27,28). Many studies have shown that these bacteria enter a viablebut-nonculturable state when water temperatures average less than 15°C and temperatures above 20°C favor their growth (23,24,25,26,28). Salinity is also an important parameter influencing the dynamics of human-pathogenic vibrios in aquatic systems.

Virulence‐associated factors in Vibrio cholerae non‐O1/non‐O139 and V. mimicus strains isolated in ornamental fish species

“…The pathogenicity of V. cholerae O1 and O139 strains depends on a combination of properties, including the secretion of a potent cholera toxin (CT) responsible for the diarrhoea characteristic of cholera, and the ability to adhere to and use the colonization factor, toxin‐coregulated pilus (TCP) to colonize the small intestine (Bishop‐Lilly et al., ; Rivera, Chun, Huq, Saq, & Colwell, ). The non‐epidemic serogroups of V. cholerae , referred to as non‐O1/non‐O139, are instead reported to cause sporadic episodes of diarrhoea and gastrointestinal infections linked to the ingestion of contaminated water, raw or undercooked seafood products, and exposure of skin wounds to sea water (Austin, ; Ceccarelli et al., ; Esteves et al., ). They generally do not produce CT, but other virulence factors can contribute to their pathogenicity, including the heat‐stable enterotoxin NAG‐ST, the haemolysin gene hlyA , the cytotoxic actin cross‐linking repeats‐in‐toxin gene rtxA, and the regulatory genes ToxR and ToxT (Ceccarelli et al., ; Rivera et al., ).…”

Growth-Inhibitory Effect of d -Tryptophan on Vibrio spp. in Shucked and Live Oysters

“…(1,2). V. parahaemolyticus is implicated as the primary source of seafood-associated human gastroenteritis in the United States (3), whereas V. vulnificus is associated with a high fatality rate (approximately 50%) and is responsible for 95% of all the seafood-related deaths in the United States (4,5).…”

Managing the risk of Vibrio parahaemolyticus infections associated with oyster consumption: A review

“…(2017) showed that a one‐unit decrease in salinity increased the concentration of V. parahaemolyticus in oysters by up to 8%. Furthermore, changes in salinity could also affect the community composition of phytoplankton, zooplankton, and planktonic crustaceans (Esteves et al., 2015; Turner, Good, Cole, & Lipp, 2009). Consequently, these conditions may affect the abundance of V. parahaemolyticus in oysters culture environments because planktons could be vectors for V. parahaemolyticus (Frischkorn, Stojanovski, & Paranjpye, 2013; Hsieh, Fries, & Noble, 2007; Jahid, Mizan, Ha, & Ha, 2015; Shime‐Hattori et al., 2006).…”