Induction of viable but nonculturable state in Vibrio parahaemolyticus and its susceptibility to environmental stresses
Article first published online: 14 JAN 2004
Journal of Applied Microbiology
Volume 96, Issue 2, pages 359–366, February 2004
How to Cite
Wong, H.C. and Wang, P. (2004), Induction of viable but nonculturable state in Vibrio parahaemolyticus and its susceptibility to environmental stresses. Journal of Applied Microbiology, 96: 359–366. doi: 10.1046/j.1365-2672.2004.02166.x
- Issue published online: 14 JAN 2004
- Article first published online: 14 JAN 2004
- 2002/347: received 3 September 2002, revised 28 August 2003 and accepted 23 October 2003
- environmental stress;
- viable but nonculturable state;
- Vibrio parahaemolyticus
Aims: This work analysed factors that influence the induction of viable but nonculturable (VBNC) state in the common enteric pathogen, Vibrio parahaemolyticus. The susceptibility of the VBNC cells to environmental stresses was investigated.
Methods and Results: Bacterium was cultured in tryptic soy broth-3% NaCl medium, shifted to a nutrient-free Morita mineral salt-0·5% NaCl medium (pH 7·8) and further incubated at 4°C in a static state to induce the VBNC state in 28–35 days. The culturability and viability of the cells were monitored by the plate count method and the Bac Light viable count method, respectively. Cells grown at the optimum growth temperature and in the exponential phase better induced the VBNC state than those grown at low temperature and in the stationary phase. Low salinity of the medium crucially and markedly shortened the induction period. The VBNC cells were highly resistant to thermal (42, 47°C), low salinity (0% NaCl), or acid (pH 4·0) inactivation.
Conclusions: Optimal conditions for inducing VBNC V. parahaemolyticus were reported. The increase in resistance of VBNC V. parahaemolyticus to thermal, low salinity and acidic inactivation verified that this state is entered as part of a survival strategy in an adverse environment.
Significance and Impact of the Study: The methods for inducing VBNC V. parahaemolyticus in a markedly short time will facilitate further physiological and pathological study. The enhanced stress resistance of the VBNC cells should attract attention to the increased risk presented by this pathogen in food.