title: Natural plant products inhibits growth and alters the swarming motility, biofilm formation, and expression of virulence genes in enteroaggregative and enterohemorrhagic Escherichia coli.
abstract: The purpose of this study was to determine the effects of plant products on the growth, swarming motility, biofilm formation and virulence gene expression in enterohemorrhagic Escherichia coli O157:H7 and enteroaggregative E. coli strain 042 and a strain of O104:H4 serotype. Extracts of Lippia graveolens and Haematoxylon brassiletto, and carvacrol, brazilin were tested by an antimicrobial microdilution method using citral and rifaximin as controls. All products showed bactericidal activity with minimal bactericidal concentrations ranging from 0.08 to 8.1 mg/ml. Swarming motility was determined in soft LB agar. Most compounds reduced swarming motility by 7%-100%; except carvacrol which promoted motility in two strains. Biofilm formation studies were done in microtiter plates. Rifaximin inhibited growth and reduced biofilm formation, but various concentrations of other compounds actually induced biofilm formation. Real time PCR showed that most compounds decreased stx2 expression. The expression of pic and rpoS in E. coli 042 were suppressed but in E. coli O104:H4 they varied depending on compounds. In conclusion, these extracts affect E. coli growth, swarming motility and virulence gene expression. Although these compounds were bactericidal for pathogenic E. coli, sublethal concentrations had varied effects on phenotypic and genotypic traits, and some increased virulence gene expression.
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, San Nicolás, N.L., 66451, Mexico.
authors.forename: Alam
authors.initials: A
authors.lastname: García-Heredia
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, San Nicolás, N.L., 66451, Mexico.
authors.forename: Santos
authors.initials: S
authors.lastname: García
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, San Nicolás, N.L., 66451, Mexico.
authors.forename: José Ángel
authors.initials: JÁ
authors.lastname: Merino-Mascorro
authors.affiliation: Division of Microbiology, Food and Drug Administration, College Park, MD, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Feng
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, San Nicolás, N.L., 66451, Mexico. Electronic address: norma@microbiosymas.com.
authors.forename: Norma
authors.initials: N
authors.lastname: Heredia
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D054324:Enterohemorrhagic Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics; D015870:Gene Expression; D005838:Genotype; D008826:Microbial Sensitivity Tests; D031341:Origanum; D010641:Phenotype; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction; D012294:Rifamycins / Q000494:pharmacology; D000078262:Rifaximin; D012697:Serine Endopeptidases / Q000235:genetics; D022641:Shiga Toxin 2 / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology; D012808:Sigma Factor / Q000235:genetics; D014774:Virulence / Q000187:drug effects / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010936:Plant Extracts; D012294:Rifamycins; D022641:Shiga Toxin 2; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; C541114:Pic protein, E coli; D012697:Serine Endopeptidases; D000078262:Rifaximin
keywords: EAEC; EHEC; Escherichia coli; Natural products; Virulence factors