Temporal and Spatial Variation in the Abundance of Total and Pathogenic Vibrio parahaemolyticus in Shellfish in China

Abstract

We investigated the abundance of total and pathogenic Vibrio parahaemolyticus in shellfish sampled from four provinces in China during May 2013 and March 2014 using the most probable number-polymerase chain reaction (MPN-PCR) method. Total V. parahaemolyticus was detected in 67.7% of 496 samples. A total of 38.1% and 10.1% of samples exceeded 1,000 MPN g-1 and 10,000 MPN g-1, respectively. V. parahaemolyticus densities followed a seasonal and geographical trend, with Guangxi and Sichuan shellfish possessing total V. parahaemolyticus levels that were 100-fold higher than those of the Liaoning and Shandong regions. Moreover, the levels of V. parahaemolyticus were at least 10-fold higher in the summer and autumn than in the cooler seasons. Pathogenic V. parahaemolyticus levels were generally lower than total V. parahaemolyticus levels by several log units and tended to be high in samples contaminated with high total V. parahaemolyticus levels. The aqua farms had a lower prevalence but higher abundance of total V. parahaemolyticus compared to retail markets. The catering markets showed the lowest levels of total V. parahaemolyticus, but 20.0% of samples exceeded 1,000 MPN g-1. The levels of both total and pathogenic V. parahaemolyticus in oysters were higher than in clams. The log-transformed abundance of V. parahaemolyticus was significantly correlated with both water temperature and air temperature but not water salinity. These results provide baseline contamination data of V. parahaemolyticus in shellfish in China, which can be applied to local risk assessments to prioritize risk control to key sectors and evaluate the effectiveness of future control measures.

Type III Secretion 1 Effector Gene Diversity Among Vibrio Isolates From Coastal Areas in China

“…In this study, we obtained 19 different Vibrio species from the coastal areas of South China and the Jiangsu province, and the most abundant species were found to be V. parahaemolyticus, V. alginolyticus, and V. harveyi. This was in agreement with the previous reports indicating that the members of the harveyi clade are usually the dominant groups in Chinese coastal environments (Xie et al, 2005;Austin and Zhang, 2006;Chen et al, 2011;Han et al, 2015;Zuo et al, 2019).…”

Characterization of clinical Vibrio parahaemolyticus strains in Zhoushan, China, from 2013 to 2014

“…In addition, a distinctive eighth open reading frame of the filamentous phage f237, orf8 , has been suggested as an useful genetic marker for identification of those pathogenic strains [13–15]. …”

Vibrio bacteria in raw oysters: managing risks to human health

“…One notable exception is presented by Han et al [51], who found significant correlations between total and pathogenic V. parahaemolyticus in oysters, despite a ratio between the two that varied widely. However, most pathogenic strains in that study were obtained from Chinese markets, rather than directly from the environment, and the authors remark that handling practices could alter pathogenic V. parahaemolyticus levels [51].…”