Survival and physiological responses of Vibrio parahaemolyticus to starvation in warm seawater

Log-phase cells of pathogenic Vibrio parahaemolyticus were incubated in warm seawater for starvation studies. The results showed that: the number of total bacteria, viable bacteria and culturable bacteria of V. parahaemolyticus all increased remarkably at the initial starvation stage; after reaching theirs peak at 15 d, both total bacterial number and viable bacterial number of V. parahaemolyticus fell slowly, while the CFU number fell more quickly after reaching its peak at 10 d; starved cells shrunk their volumes and turned their shapes into ovals from short rods; starved cells showed more sensitivity to heat and UV; there was no significant difference in the lowest detection limit between starved cells and log-phase ones determined by ELISA; starved cells exhibited a sharply decline in the adherence to skin mucus of large yellow croaker and no specific adhesion was found after starved for 7 d and more; starved cells were less virulent to mouse; the cellular protein of V. parahaemolyticus decreased remarkably at the initial stage of starvation and increased a little at the latter stage. The results indicated that: pathogenic V. parahaemolyticus might survive starvation for a long time in the warm seawater profit from the morphological and physiological changes; the starved cells were less virulent and more sensitive to environmental stresses.