Influence of pH on bile sensitivity among various strains of Listeria monocytogenes under aerobic and anaerobic conditions.

In this study the survival of strains representing six serotypes were analyzed under aerobic and anaerobic conditions following exposure to bile. Exposure to bile salts at acidic pH increased toxicity of bile, resulting in a significant reduction in survival for all strains tested. However, following this initial reduction, no significant reduction was observed for an additional two hours except for 10403S (P = 0.002). Anaerobic cultivation increased bile resistance, but a significant increase was only observed in virulent strains when exposed to bile at pH of 5.5. Exposure to pH 3.0 prior to bile decreased viability among avirulent strains in bile at acidic conditions; oxygen availability did not influence viability. Together these data suggest that being able to sense and respond to oxygen availability may influence the expression of stress response mechanisms and that this response may correspond to disease outcome. Further research is needed on additional strains to determine how L. monocytogenes sense and respond to oxygen and how this varies between invasive and non-invasive strains. PMID: 26307079 [PubMed - as supplied by publisher]
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research