Pandemic Vibrio parahaemolyticus O3:K6 on the American continent

Abstract

Vibrio parahaemolyticus is one of the most important seafood-borne bacterial in recent years and is the leading causal agent of human acute gastroenteritis, primarily following the consumption of raw, undercooked or mishandled marine products. Until 1996, infections caused by V. parahaemolyticus were generally associated with diverse serovars. However, in February 1996, a unique serovar (O3:K6) of V. parahaemolyticus with specific genetic markers (tdh, toxRS/New and/or orf8) appeared abruptly in Kolkata, India. In subsequent years, O3:K6 isolates similar to those isolated in Kolkata have been reported from food borne outbreaks in Southeast Asia, as well as in the Atlantic and Gulf coasts of the United States (U.S). More recently, there have been reports in Europe, Africa and Central and South America. Specifically, in the American continent, some countries have reported cases of gastroenteritis due to the pandemic O3:K6 strain and its serovariants; the pandemic strain was first detected in Peru (1996, >100 cases), subsequently spreading to Chile in 1998 (>16,804 human cases), to the U.S. in 1998 (>700 cases), to Brazil in 2001 (>18 cases) and to Mexico in 2004 (>1200 cases). The arrival of the pandemic clone on the American continent may have resulted in a significant shift on the epidemic dynamics of V. parahaemolyticus. However, although O3:K6 is the predominant serovar of the recognized clinical strains in some countries in the Americas, a decrease in clinical cases caused by O3:K6 and an increase in cases associated with a new serotype (O3:K59, Chile) have been recently reported. The emergence and worldwide dissemination of O3:K6 and other pandemic strains since 1996 have come to represent a threat to public health and should concern health authorities. This review focuses on the presence, distribution and virulence factors of the V. parahaemolyticus O3:K6 pandemic clone and its serovariants in clinical and environmental strains on the American continent.

Association of CRISPR/Cas Evolution withVibrio parahaemolyticusVirulence Factors and Genotypes

“…Therefore, we hypothesize that CST3 and CST5 may have directly evolved from the CST4 group. The CC3, which contained O3:K6 and its serovariants, has been detected throughout the world as a pandemic pathogen (Nair et al, 2007;Chao et al, 2011;Velazquez-Roman et al, 2013). Similarly, the CST3 group has become the pandemic V. parahaemolyticus strains in China; it remains to be determined whether the CST5 group will develop a pandemic strain.…”

Environmental parameters influence on the dynamics of total and pathogenic Vibrio parahaemolyticus densities in Crassostrea virginica harvested from Mexico’s Gulf coast

“…V. parahaemolyticus tdh+/trh+ has been reported previously by Johnson et al (2009) in oyster samples along the Mississippi Gulf Coast during the spring season with a prevalence of 5.95%, being most of the tdh+ isolates (85%) also trh+. Also, coastal contamination with V. parahaemolyticus carrying genetic markers associated with pandemic strains (tdh/orf8) has been reported worldwide (Ceccarelli et al, 2013;Velázquez-Roman et al, 2014). Moreover, in limited areas of Northwest Mexico on the Pacific coast, increased proportions (48-52%) of strains with pathogenic markers (tdh and/ or trh) have been detected in environmental strains isolated from water, fish, sediment, and shrimp (Cabanillas-Beltrán et al, 2006;Velázquez-Roman et al, 2012).…”

Vibrio parahaemolyticus virulence determinants

“…However, a major change in the epidemiology of V. parahaemolyticus occurred at the beginning of that year, when an atypical outbreak of diarrhea in Kolkata, India, was attributed to the emergence of a new clonal group of the V. parahaemolyticus serotype O3:K6 (the O and K antigens referring to somatic and capsular antigens, respectively) [11]. Ongoing surveillance in Kolkata identified this serogroup as accountable for 50-80% of infections occurring over the subsequent months [12,13]. The O3:K6 serogroup rapidly spread to neighboring countries, including Vietnam, Indonesia, Bangladesh, Laos, Japan, Korea, and Thailand [7].…”

“…In the following years, environmental and clinical serovariants of the O3:K6 strain identified in Kolkata were found in the United States, Mexico, South America [2,13], Europe [14], and Africa [15]. This is considered to be the emergence of the first pandemic strain of V. parahaemolyticus [13].…”