The plasmid-borne cadAC genes confer cadmium resistance ( 17, 23) and were also found in pLM58 ( Table 3). In order to confirm whether pLM58 is self-transmissible, standard plate mating was performed between strains AT3E and 10403S. Site-specific recombinase resolvase family Prolipoprotein diacylglyceryl transferase L-Proline glycine betaine ABC transport system monocytogenes have been reported ( 8, 12), investigations are required to reveal the accessory genetic mechanisms that provide certain strains with enhanced heat resistance. While the general heat stress properties and adaptation responses of L. reported a 3-log-unit difference in the heat resistance (log 10 reduction) of L. monocytogenes strains in their ability to survive high temperatures ( 10, 11). However, distinct differences exist between L. monocytogenes to subsequent heat stress as well as other stressors encountered in food production, such as NaCl and ethanol ( 7, 10). Furthermore, a previous heat treatment may enhance the tolerance and adaptation of L. monocytogenes can grow at 45☌ and is more heat resistant than most other non-spore-forming food-borne pathogens ( 1, 9). In addition, it is able to cope with many stress conditions used for controlling bacterial contamination, including high temperatures ( 7, 8). monocytogenes may persist in food-processing premises for several years ( 5, 6), which makes it a challenging contaminant in food production. Listeria monocytogenes is a Gram-positive, non-spore-forming food-borne pathogen and the causative agent of listeriosis, a severe human illness with mortality reaching 35% ( 1 – 4). monocytogenes strains particularly capable of surviving high temperatures-with plasmid-borne ClpL being a potential predictor of elevated heat resistance. monocytogenes, our study sheds light on the accessory genetic mechanisms rendering certain L. As the first report on plasmid-mediated heat resistance in L.
Whole-genome-sequence analysis and phenotypic characterization allowed us to identify a novel plasmid, designated pLM58, and a plasmid-borne ATP-dependent protease (ClpL), which mediated heat resistance in L.
monocytogenes strains differ in their ability to survive high temperatures, and comprehensive understanding of the genetic mechanisms underlying these differences is still limited. This poses a risk to food safety, as listeriosis is commonly associated with ready-to-eat foods that are consumed without thorough heating. monocytogenes is among the most heat-resistant non-spore-forming bacteria. IMPORTANCE Listeria monocytogenes is a dangerous food pathogen causing the severe illness listeriosis that has a high mortality rate in immunocompromised individuals. Plasmid-borne ClpL is thus a potential predictor of elevated heat resistance in L. monocytogenes strain (1.2 CFU/ml log 10 reduction) significantly increased the heat resistance of the recipient strain (0.4 CFU/ml log 10 reduction) at 55☌. Introducing the clpL gene into a natively heat-sensitive L. pLM58 harbored a 2,115-bp open reading frame annotated as an ATP-dependent protease (ClpL)-encoding clpL gene. Indeed, plasmid curing resulted in significantly decreased heat resistance (1.1 CFU/ml log 10 reduction) at 55☌. A prominent difference in the genome compositions of the two strains was a 58-kb plasmid (pLM58) harbored by the heat-resistant AT3E strain, suggesting plasmid-mediated heat resistance. monocytogenes AT3E was more heat resistant (0.0 CFU/ml log 10 reduction) than strain AL4E (1.4 CFU/ml log 10 reduction) after heating at 55☌ for 40 min. monocytogenes strains-both of serotype 1/2c, sequence type ST9, and high sequence identity-at high temperatures and compared their genome composition in order to identify genetic mechanisms involved in their heat survival phenotype. We tested the survival of two wild-type L. This resistance is mediated by the ATP-dependent protease ClpL. Here, we report plasmid-mediated heat resistance of L. monocytogenes strains with the advantage of enhanced heat resistance are unknown. monocytogenes have been described, accessory mechanisms providing particular L. While general heat stress properties and response mechanisms of L. Listeria monocytogenes is one of the most heat-resistant non-spore-forming food-borne pathogens and poses a notable risk to food safety, particularly when mild heat treatments are used in food processing and preparation.
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