title: Survival of Listeria monocytogenes in simulated gastrointestinal system and transcriptional profiling of stress- and adhesion-related genes.
abstract: Food ingestion is the major route of exposure to the important human pathogen Listeria monocytogenes. An in vitro gastrointestinal model was used to (1) compare the survival rates of L. monocytogenes strains of serotypes 1/2a, 1/2c, and 4b; and (2) examine the transcription of stress- and adhesion-related genes after exposure to the conditions similar to those encountered in the mouth, stomach, and small intestine. None of the L. monocytogenes strains investigated could survive in the gastric juice at pH 2.5 or 3.0. Their survival increased at higher pH (3.5 and 4.0) in the gastric stress. Relative survival of L. monocytogenes serotypes 4b and 1/2a strains were higher than that of serotype 1/2c, suggesting that pathogenicity might be related to the viability in the gastrointestinal tract. The transcription levels of prfA and the general stress-related genes clpC, clpE, and clpP were upregulated after passing through the simulated gastrointestinal tract, whereas that of the adhesion-related gene ami was downregulated. Taken together, this study revealed that L. monocytogenes strains enhanced the expression of stress-related genes and decreased the transcription of adhesion-related gene in order to survive in the diverse microenvironments.
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine, and Zhejiang Provincial Key Laboratory for Preventive Veterinary Medicine, Hangzhou, Zhejiang, People's Republic of China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Jiang
authors.forename: Inger
authors.initials: I
authors.lastname: Olesen
authors.forename: Thomas
authors.initials: T
authors.lastname: Andersen
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
authors.forename: Lene
authors.initials: L
authors.lastname: Jespersen
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D001422:Bacterial Adhesion / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D005750:Gastric Juice / Q000737:chemistry / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007422:Intestines / Q000382:microbiology; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D010454:Peptide Termination Factors / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012463:Saliva / Q000382:microbiology; D012703:Serotyping; D013312:Stress, Physiological / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; D006360:Heat-Shock Proteins; D010454:Peptide Termination Factors; C545356:PrfA protein, Listeria monocytogenes; D012333:RNA, Messenger; D000251:Adenosine Triphosphatases; C118340:ClpE protein, bacteria