Identification and characterization of a pathogenic Vibrio parahaemolyticus causing translucent post-larvae disease in Penaeus vannamei

Penaeus vannamei is an important aquaculture species, but disease outbreaks posed a serious threat to the sustainable development of shrimp farming. In recent years, a fatal disease known as translucent post-larvae disease (TPD) has emerged in many farms, characterized by the vacuolization of the hepatopancreas and the pallor or colorlessness of the intestine. In this study, we obtained a strain of Vibrio parahaemolyticus, named H1, that could cause TPD in both juvenile and adult shrimps. V. parahaemolyticus H1 could cause gradual atrophy of the hepatopancreas, deepening of the intracellular material color, and eventually complete vacuolization. Antibiotic susceptibility tests revealed that V. parahaemolyticus H1 was resistant to chloramphenicol, ceftriaxone, and sulfamethoxazole trimethoprim, but exhibited resistance to tetracycline. The 2b-RAD-M analysis showed that V. parahaemolyticus H1 could disrupt the shrimp intestinal microbiota and lead to a loss of resistance to environmental bacteria. These results identified a pathogenic V. parahaemolyticus causing TPD from P. vannamei.