title: Heat stress adaptation induces cross-protection against lethal acid stress conditions in Arcobacter butzleri but not in Campylobacter jejuni.
abstract: The ability of many bacteria to adapt to stressful conditions may later protect them against the same type of stress (specific adaptive response) or different types of stresses (multiple adaptive response, also termed cross-protection). Arcobacter butzleri and Campylobacter jejuni are close phylogenetic relatives that occur in many foods of animal origin and have been linked with human illness (mainly diarrhoea). In the present study, sublethal stress adaptation temperatures (48 °C and 10 °C) and mild and lethal acid conditions (pH 5.0 and pH 4.0) were determined for A. butzleri and C. jejuni. In addition, it was evaluated whether these sublethal stress adaptations cause specific adaptive responses or cross-protection against subsequent mild or lethal acid stresses in these bacteria. The studies were conducted in broth adjusted to the different conditions and the results were determined by the dilution series plating method. It was shown that heat stress adapted A. butzleri (incubated for 2 h at 48 °C) were significantly more resistant to subsequent lethal acid stress (pH 4.0) than non-adapted cells at the 1 h time-point (p < 0.01 in Wilcoxon rank sum test). No specific adaptive responses against the stresses in A. butzleri or C. jejuni and no cross-protection in C. jejuni were found. The ability of heat stressed A. butzleri to tolerate later lethal acid conditions should be taken into account when designing new food decontamination and processing strategies.
authors.affiliation: Ruralia Institute, Seinäjoki Unit, University of Helsinki, Kampusranta 9C, FI-60320 Seinäjoki, Finland. pauliina.isohanni@helsinki.fi
authors.forename: Pauliina
authors.initials: P
authors.lastname: Isohanni
authors.forename: Stephan
authors.initials: S
authors.lastname: Huehn
authors.forename: Tommi
authors.initials: T
authors.lastname: Aho
authors.forename: Thomas
authors.initials: T
authors.lastname: Alter
authors.forename: Ulrike
authors.initials: U
authors.lastname: Lyhs
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000222:Adaptation, Physiological; D020640:Arcobacter / Q000187:drug effects / Q000502:physiology*; D016123:Campylobacter jejuni / Q000187:drug effects / Q000502:physiology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability / Q000187:drug effects
chemical_list: D000143:Acids