Tolerance and starvation induced cross-protection against different stresses in Aeromonas hydrophila.
Aeromonas hydrophila is sometimes considered as a controversial human pathogen and reported to be susceptible to food processing procedures and environmental stresses. In this study, we have shown that early stationary phase cells of A. hydrophila were readily killed during up shifts in temperature (in the range 50-70 degrees C), the course of drying (at relative humidity, temperature and brightness of the laboratory) and after 5 min exposure to 20%, 30% and 40% v/v ethanol. However, this bacterium was found moderately susceptible to down shift to 4 degrees C in nutrient poor water, sodium chloride stresses (1.5 and 2 M) and to 12% and 15% v/v ethanol stresses. Tolerance against 1 M NaCl and 10% v/v ethanol was observed. At ambient temperature (24.5 degrees C), this microorganism exhibited a starvation survival state, which was largely independent of the initial cell concentrations (8.82, 7.71 and 6.76 log units). The cross-protection experiments showed that cells starved for short (1 day) or prolonged (50 days) periods developed increased resistance to down shift at 4 degrees C and ethanol stress. This may be of concern to the food-processing industry from the public health perspective.
Mary
Patrice
P
Laboratoire de Microbiologie, Université des Sciences et Technologies de Lille, Bâtiment SN2, F-59655 Villeneuve d'Ascq Cedex, France. Patrice.Mary@univ-lille1.fr
Sautour
Marc
M
Chihib
Nour-Eddine
NE
Tierny
Yann
Y
Hornez
Jean-Pierre
JP
D000222:Adaptation, Physiological; D016980:Aeromonas hydrophila / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006813:Humidity; D012965:Sodium Chloride / Q000494:pharmacology; D013217:Starvation / Q000503:physiopathology; D013696:Temperature; D013997:Time Factors
D000891:Anti-Infective Agents, Local; D000431:Ethanol; D012965:Sodium Chloride