Abstract
Propionate is a common food preservative and one of the major fermentation acids in the intestines. Therefore, exposure to propionate is frequent for foodborne pathogens and likely takes place under suboxic conditions. However, it is not clear whether the absence of oxygen affects how pathogens respond to propionate. Here, we investigated how propionate exposure affects Listeria monocytogenes growth and virulence factor production under aerobic or anaerobic conditions and showed that oxygen indeed plays a key role in modulating L. monocytogenes response to propionate. Under aerobic conditions, propionate supplementations had no effect on planktonic growth but resulted in decreased adherent growth. Under anaerobic conditions, propionate supplementations resulted in a pH-dependent inhibition of planktonic growth and increased adherent growth. Cultures grown with propionate accumulated higher levels of acetoin under aerobic conditions but lower levels of ethanol under both aerobic and anaerobic conditions. Metabolic perturbations by propionate were also evident by the increase in straight chain fatty acids. Finally, propionate supplementations resulted in increased listeriolyin O (LLO) production under anaerobic conditions but decreased LLO production under aerobic conditions. These results demonstrate for the first time that the presence or absence of oxygen plays a critical role in shaping L. monocytogenes responses to propionate.
Highlights
Listeria monocytogenes is a ubiquitous bacterium that frequently enters into human food supply chains and causes fatal infections
We investigated the effects of propionate on L. monocytogenes growth and virulence factor production to obtain a better understanding of L. monocytogenes response to propionate under aerobic and anaerobic conditions
We tested the effects of propionate on L. monocytogenes growth in brain heart infusion (BHI) buffered at pH 6.0, 7.0, or 8.0 and found a pH-dependent effects of propionate under aerobic but not anaerobic conditions
Summary
Listeria monocytogenes is a ubiquitous bacterium that frequently enters into human food supply chains and causes fatal infections. L. monocytogenes alone is responsible for approximately. 19% of annual deaths caused by foodborne infections [1]. The high mortality rate of L. monocytogenes infections is attributed to the virulence of outbreak strains and the immunocompromised states of infected individuals. The ubiquity of L. monocytogenes is attributed to the unique ability of L. monocytogenes to survive and grow through common food preservation strategies such as refrigeration [2]. L. monocytogenes surveillance is a crucial approach to prevent exposure and, as a routine practice, often results in frequent and costly food recalls. To ensure food safety, reducing L. monocytogenes contamination in the food production and distribution is a challenging but necessary action
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
