title: Streptococcus pneumoniae contains 3 rlrA pilus variants that are clonally related.
abstract: BACKGROUND
  Pilus components of Streptococcus pneumoniae encoded by rlrA were recently shown to elicit protection in an animal model of infection. Limited data are available on the prevalence of the rlrA operon in pneumococci; therefore, we investigated its distribution and its antigenic variation among disease-causing strains.
  
  
  METHODS
  The prevalence of rlrA and its association with serotype and genotype were evaluated in a global panel of 424 pneumococci isolates (including the 26 drug-resistant clones described by the Pneumococcal Molecular Epidemiology Network).
  
  
  RESULTS
  The rlrA islet was found in 130 isolates (30.6%) of the defined collection. Sequence alignment of 15 rlrA islets defined the presence of 3 clade types, with an overall homology of 88%-92%. The presence or absence of a pilus-encoding operon correlated with S. pneumoniae genotype (P < .001), as determined by multilocus sequence typing, and not with serotype. Further investigation identified a positive trend of rlrA occurrence among antimicrobial-resistant pneumococci.
  
  
  CONCLUSIONS
  On the basis of S. pneumoniae genotype, it is possible to predict the incidence of the rlrA pilus operon in a collection of pneumococcal isolates. This will facilitate the development of a protein vaccine.
authors.affiliation: Novartis Vaccines, Siena, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Moschioni
authors.forename: Claudio
authors.initials: C
authors.lastname: Donati
authors.forename: Alessandro
authors.initials: A
authors.lastname: Muzzi
authors.forename: Vega
authors.initials: V
authors.lastname: Masignani
authors.forename: Stefano
authors.initials: S
authors.lastname: Censini
authors.forename: William P
authors.initials: WP
authors.lastname: Hanage
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Bishop
authors.forename: Joice Neves
authors.initials: JN
authors.lastname: Reis
authors.forename: Staffan
authors.initials: S
authors.lastname: Normark
authors.forename: Birgitta
authors.initials: B
authors.lastname: Henriques-Normark
authors.forename: Antonello
authors.initials: A
authors.lastname: Covacci
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
authors.forename: Michèle A
authors.initials: MA
authors.lastname: Barocchi
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial; D010861:Fimbriae, Bacterial / Q000235:genetics* / Q000502:physiology; D020440:Gene Duplication; D014644:Genetic Variation; D044404:Genomic Islands; D005838:Genotype; D006801:Humans; D009876:Operon; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D015534:Trans-Activators / Q000235:genetics*; D014774:Virulence / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D015534:Trans-Activators; C470697:rlrA protein, Streptococcus pneumoniae