A comparison of solid and liquid media for resuscitation of starvation- and low-temperature-induced nonculturable cells of Aeromonas hydrophila.

Like many other gram-negative bacteria, starved cells of Aeromonas hydrophila can be induced into a viable but nonculturable (VBNC) state by incubation at low temperature, as shown here by using various bacterial enumeration methods. Starved A. hydrophila strain HR7 cells at 4 degrees C reached the nonculturable stage in about 45 days. The cells were resuscitated by either a solid medium resuscitation method, using solid agar amended with H2O2-degrading agents, catalase or sodium pyruvate, or a liquid medium resuscitation method, by incubating nonculturable cells in liquid media containing these compounds before spreading onto plates. The liquid medium resuscitation method using catalase resulted in nearly complete recovery of nonculturable cells.