title: Changes in lipopolysaccharide profile of Porphyromonas gingivalis clinical isolates correlate with changes in colony morphology and polymyxin B resistance.
abstract: Virulence factors on the surface of Porphyromonas gingivalis constitute the first line of interaction with host cells and contribute to immune modulation and periodontitis progression. In order to characterize surface virulence factors present on P. gingivalis, we obtained clinical isolates from healthy and periodontitis subjects and compared them with reference strains. Colony morphology, aggregation in liquid medium, surface charge, membrane permeability to bactericidal compounds, novobiocin and polymyxin B resistance, capsule presence and lipopolysaccharide (LPS) profiles were evaluated. By comparing isolates from healthy and periodontitis subjects, differences in colony morphology and aggregation in liquid culture were found; the latter being similar to two reference strains. These differences were not a consequence of variations in bacterial surface charge. Furthermore, isolates also presented differences in polymyxin B and novobiocin resistance; isolates from healthy subjects were susceptible to polymyxin B and resistant to novobiocin and, in contrast, isolates from periodontitis subjects were resistant to polymyxin B and susceptible to novobiocin. These changes in antimicrobial resistance levels correlate with variations in LPS profiles, since -unlike periodontitis isolates-isolates from healthy samples synthesize LPS molecules lacking both O-antigen moieties and anionic polysaccharide. Additionally, this phenotype correlated with the absence of O-antigen ligase activity. Altogether, our results reveal novel variations on surface components of P. gingivalis isolates obtained from healthy and periodontitis subjects that could be associated with differences in bacterial virulence and periodontitis progression.
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Leonor
authors: L
authors: Díaz
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Anilei
authors: A
authors: Hoare
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Cristopher
authors: C
authors: Soto
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Isaac
authors: I
authors: Bugueño
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Nora
authors: N
authors: Silva
authors: Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Nicolás
authors: N
authors: Dutzan
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Darna
authors: D
authors: Venegas
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Daniela
authors: D
authors: Salinas
authors: BioNanotechnology and Microbiology Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, Santiago, Chile.
authors: José Manuel
authors: JM
authors: Pérez-Donoso
authors: Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
authors: Jorge
authors: J
authors: Gamonal
authors: Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile. Electronic address: denbravo@uchile.cl.
authors: Denisse
authors: D
authors: Bravo
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016866:Bacteroidaceae Infections / Q000382:microbiology; D016022:Case-Control Studies; D002463:Cell Membrane Permeability; D024881:Drug Resistance, Bacterial; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D008070:Lipopolysaccharides / Q000378:metabolism*; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010518:Periodontitis / Q000382:microbiology*; D011112:Polymyxin B / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D037521:Virulence Factors; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D008070:Lipopolysaccharides; D012336:RNA, Ribosomal, 16S; D037521:Virulence Factors; D011112:Polymyxin B
keywords: Chronic periodontitis; Clinical isolates; Lipopolysaccharide; Polymyxin B; Porphyromonas gingivalis