Effects of Nutritional Conditions and Exogenous N-Acyl-Homoserine Lactones on the Resuscitation of Sodium Hypochlorite-Induced Dormant Vibrio parahaemolyticus

This study investigated the effects of nutritional conditions and exogenous N-acyl-homoserine lactones (AHLs) on the recovery of sodium hypochlorite (NaClO)-induced viable but non-culturable (VBNC) Vibrio parahaemolyticus. Exposure to 40 mg/L NaClO for 20 min resulted in the loss of culturability while viable cells (approximately 1.19 × 102 cells/mL) remained detectable by SYTO9/PI staining, consistent with the operational criteria for the VBNC state. Five resuscitation systems were evaluated, including tryptic soy broth (TSB) alone, heat treatment, TSB supplemented with sodium pyruvate, TSB supplemented with Tween 80, and TSB supplemented with five AHLs (C4-HSL, C6-HSL, C8-HSL, OHHL, and 3-oxo-C14-HSL). Among the tested systems, the AHL-supplemented medium showed the highest recovery efficiency, characterized by a shortened lag phase, colony characteristics and cellular morphology approaching those of normal cells, increased intracellular ATP levels, and respiratory chain activity approaching normal levels. RT-qPCR analysis showed significantly increased expression of quorum sensing- and stress response-related genes, including opaR, atpA, soxR, and katG, in the AHL-treated group compared with the TSB group. These findings suggest that AHL supplementation is associated with enhanced recovery of VBNC V. parahaemolyticus and may facilitate metabolic reactivation during this process.