title: Characterization of Serratia marcescens isolates from subgingival biofilm, extraoral infections and environment by prodigiosin production, serotyping, and genotyping.
abstract: BACKGROUND
  Serratia marcescens is widely distributed in nature, and has emerged in the last years as an important nosocomial pathogen. The organism may also be found in subgingival biofilm in periodontitis patients. This study aimed to verify the subgingival prevalence of S. marcescens in different periodontal conditions and to evaluate whether the oral cavity would harbor strains similar to those causing infectious diseases.
  
  
  METHODS
  The subgingival occurrence of S. marcescens was determined in 334 subjects. The phenotypic and genotypic diversity of 23 isolates from subgingival biofilm, 22 from extra-oral infections and 10 environmental strains, was compared by prodigiosin production, O and H serotyping and genotyping using polymorphic GC-rich repetitive sequences-polymerase chain reaction.
  
  
  RESULTS
  S. marcescens was found more frequently in severe periodontitis patients (4.1%) than in gingivitis (3.2%) and healthy subjects (2.5%), but these differences were not statistically significant. Analysis of serotype distribution, prodigiosin production, and genotyping revealed that environmental strains were markedly different from most human isolates, either oral or extraoral.
  
  
  CONCLUSIONS
  These data suggest that S. marcescens isolates from subgingival biofilm are not just contaminants from the environment, but that the oral cavity may act as a reservoir of strains able to promote human infections. However, further studies are needed to elucidate the role of this bacterium in the pathogenesis of periodontal diseases.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Brazil.
authors.forename: F C B
authors.initials: FC
authors.lastname: Barbosa
authors.forename: K
authors.initials: K
authors.lastname: Irino
authors.forename: G V
authors.initials: GV
authors.lastname: Carbonell
authors.forename: M P A
authors.initials: MP
authors.lastname: Mayer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000032:analysis; D000942:Antigens, Bacterial / Q000032:analysis; D018441:Biofilms; D004783:Environmental Microbiology; D005260:Female; D020862:GC Rich Sequence / Q000235:genetics; D005838:Genotype; D005881:Gingiva / Q000382:microbiology*; D005891:Gingivitis / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019081:O Antigens / Q000032:analysis; D010518:Periodontitis / Q000382:microbiology; D011353:Prodigiosin / Q000032:analysis / Q000096:biosynthesis; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D012703:Serotyping; D016868:Serratia Infections / Q000382:microbiology*; D012706:Serratia marcescens / Q000145:classification* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; C022863:H antigen; D019081:O Antigens; D011353:Prodigiosin