Prevalences of pathogenic and non-pathogenic Vibrio parahaemolyticus in mollusks from the Spanish Mediterranean Coast

Abstract

Vibrio parahaemolyticus is a well-recognized pathogen of humans. To better understand the ecology of the human-pathogenic variants of this bacterium in the environment, a study on the prevalence in bivalves of pathogenic variants (tlh+ and tdh+ and/or trh+) versus a non-pathogenic one (only tlh+ as species marker for V. parahaemolyticus), was performed in two bays in Catalonia, Spain. Environmental factors that might affect dynamics of both variants of V. parahaemolyticus were taken into account. The results showed that the global prevalence of total V. parahaemolyticus found in both bays was 14.2% (207/1459). It was, however, significantly dependent on sampling point, campaign (year) and bivalve species. Pathogenic variants of V. parahaemolyticus (tdh+ and/or trh+) were detected in 3.8% of the samples (56/1459), meaning that the proportion of bivalves who contained tlh gene were contaminated by pathogenic V. parahaemolyticus strains is 27.1% (56/207). Moreover, the presence of pathogenic V. parahaemolyticus (trh+) was significantly correlated with water salinity, thus the probability of finding pathogenic V. parahaemolyticus decreased 1.45 times with every salinity unit (ppt) increased. Additionally, data showed that V. parahaemolyticus could establish close associations with Ruditapes spp. (P-value < 0.001), which could enhance the transmission of illness to human by pathogenic variants, when clams were eaten raw or slightly cooked. This study provides information on the abundance, ecology and characteristics of total and human-pathogenic V. parahaemolyticus variants associated with bivalves cultured in the Spanish Mediterranean Coast.

Variability of planktonic and epiphytic vibrios in a coastal environment affected by <em>Ostreopsis</em> blooms

“…Although Vibrio seems to be an important pathogenic agent in the NW Mediterranean (e.g. Canigral et al 2010, Lopez-Joven et al 2015, to the best of our knowledge no information on abundance of planktonic Vibrio (using culture independent methods) is available for Mediterranean waters.…”

First multi-year retrospective study on Vibrio parahaemolyticus and Vibrio vulnificus prevalence in Ruditapes philippinarum in Sacca di Goro, Italy

“…Among the few reports, this is the case of the multiyear study performed on different shellfish, including R. philippinarum (120 samples) harvested in the Ebro Delta, Spain, from 2006 to 2010 (Lopez-Joven et al , 2014, 2015), but our results are not in agreement, because we found an higher prevalence of total V. parahaemolyticus (29.8 vs 14.2%) and potentially pathogenic V. parahaemolyticus (6.7 vs 3.3%), but a lower prevalence of total V. vulnificus (11.5 vs 22.5%).…”

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

“…Considerable improvements have been made in detecting V. parahaemolyticus in samples over the past two decades because of technological advancements. However, the detection of V. parahaemolyticus in samples is affected by numerous factors, including the substrate used for isolation, isolation methods, detection methods, and sampling period (Anupama et al., 2019; Givens et al., 2014; Lopez‐Joven, de Blas, Furones, & Roque, 2015; Pinto, Terio, Novello, & Tantillo, 2011). For example, the use of the chromogenic medium (CHROMagar Vibrio or Bio‐Chrome Vibrio medium) was found to be more effective than that of thiosulfate citrate bile salts sucrose (TCBS) agar for isolating colonies of V. parahaemolyticus (Duan & Su, 2005a; Pinto et al., 2011).…”

“…Table 1 shows examples of studies that have investigated the presence of V. parahaemolyticus in oysters collected from either culturing environments or markets in either tropical, subtropical, or temperate areas. Oyster samples collected from tropical or subtropical areas (Cook et al., 2002; Deepanjali et al., 2005; DePaola, Nordstrom, Bowers, Wells, & Cook, 2003; Han et al., 2017; Johnson et al., 2010, 2012; López‐Hernández, Pardío‐Sedas, Lizárraga‐Partida, Williams, Martínez‐Herrera, Flores‐Primo, Uscanga‐Serrano, & Rendón‐Castro, 2015; Matté, Matté, Rivera, & Martins, 1994; New et al., 2014; Sanjeev & Stephen, 1993; Sobrinho et al., 2010, 2011; Ward & Bej, 2006; Yang et al., 2017; Yu et al., 2013, 2016; Zimmerman et al., 2007) are generally considered to exhibit higher concentrations of V. parahaemolyticus than those obtained from temperate areas (Cruz et al., 2015; Duan & Su, 2005b; Fletcher, 1985; Jones et al., 2014; Kaysner, Abeyta, Stott, Krane, & Wekell, 1990; Kaysner, Abeyta, Stott, Lilja, & Wekell, 1990; Kirs et al., 2011; Lopatek, Wieczorek, & Osek, 2015; Lopez‐Joven et al., 2015; Mok et al., 2019; Nakaguchi, 2013; Park, Mok, et al., 2018; Parveen et al., 2008; Roque et al., 2009; Ryu, Mok, Lee, Kwon, & Park, 2019; Tepedino, 1982; Thomson & Thacker, 1972). For example, concentrations of V. parahaemolyticus in oysters were 94% in India, between 77% and 100% in Brazil, 100% in Mexico, and 71% in Taiwan.…”

“…Another example is the study by Lopez‐Joven et al. (2015) that investigated the presence of V. parahaemolyticus in mollusks (oysters, mussels, and clams) collected from the Ebro Delta Bays, Spanish Mediterranean Coast, and found that the source of samples was a significant factor affecting the density of this pathogen in samples. Based on logistic regression analysis, Lopez‐Joven et al.…”