Optimization of resuscitation-promoting broths for the revival of Vibrio parahaemolyticus from a viable but nonculturable state

Abstract

This study was conducted to examine the effect of formulated resuscitation-promoting broths on the revival of viable but nonculturable Vibrio parahaemolyticus induced by cold and starvation stresses. Vibrio parahaemolyticus was incubated in artificial sea water at 4 degrees C for more than 8 months until this bacterium became undetectable, while retaining its intact cell count of more than 10(5) CFU/field over time. On day 250, V. parahaemolyticus was collected and enriched in tryptic soy broth supplemented with 3% NaCl, 10,000 U/mg catalase, 2% sodium pyruvate, 20 mM MgSO4, 5 mM EDTA, and a cell-free supernatant taken from V. parahaemolyticus ATCC 17802 in the stationary phase (pH 8). V. parahaemolyticus returned partially to a culturable state with a maximal cell density of 7.91 log CFU/mL in this formulated medium following 7 days of enrichment at 25 degrees C. In contrast, no V. parahaemolyticus was resuscitated when enriched in alkaline peptone water and tryptic soy broth.