Persistent and sporadic Listeria monocytogenes strains do not differ when growing at 37 °C, in planktonic state, under different food associated stresses or energy sources

• Published in: BMC microbiology 2019-11, Vol.19 (1), p.257-257, Article 257
• Main Authors: Taylor, Alexander J, Stasiewicz, Matthew J
• Format: Article
• Language: English
• Subjects: Acids; Benzalkonium chloride; Biofilms; Cellobiose; Contamination; Defined media; Energy; Energy resources; Energy sources; Extrinsic stress; Food; Food contamination; Food processing industry; Food sources; Foodborne pathogens; Fructose; Glucose; Glycogen; Glycogens; Growth curves; Growth rate; Lactose; Listeria; Listeria monocytogenes; Listeriosis; Low temperature; Monosaccharides; Organic chemistry; Osmosis; Osmotic pressure; Pathogens; Persistence; pH effects; Phenotypes; Phenotyping; Polysaccharides; Researchers; Sodium chloride; Source studies; Stress (Psychology); Stresses; Sucrose; Sugar; Surface active agents
• ISSN: 1471-2180; 1471-2180
• DOI: 10.1186/s12866-019-1631-3

The foodborne pathogen Listeria monocytogenes causes the potentially lethal disease listeriosis. Within food-associated environments, L. monocytogenes can persist for long periods and increase the risk of contamination by continued presence in processing facilities or other food-associated environments. Most research on phenotyping of persistent L. monocytogenes' has explored biofilm formation and sanitizer resistance, with less data examining persistent L. monocytogenes' phenotypic responses to extrinsic factors, such as variations in osmotic pressure, pH, and energy source availability. It was hypothesized that isolates of persistent strains are able to grow, and grow faster, under a broader range of intrinsic and extrinsic factors compared to closely related isolates of sporadic strains. To test this hypothesis, 95 isolates (representing 74 isolates of 20 persistent strains and 21 isolates of sporadic strains) from a series of previous studies in retail delis, were grown at 37 °C, in (i) stress conditions: salt (0, 5, and 10% NaCl), pH (5.2, 7.2, and 9.2), and sanitizer (benzalkonium chloride, 0, 2, and 5 μg/mL) and (ii) energy sources: 25 mM glucose, cellobiose, glycogen, fructose, lactose, and sucrose; the original goal was to follow up with low temperature experiments for treatments where significant differences were observed. Growth rate and the ability to grow of 95 isolates were determined using high-throughput, OD , growth curves. All stress conditions reduced growth rates in isolates compared to control (p