Streptococcus pneumoniae contains 3 rlrA pilus variants that are clonally related.
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.
Moschioni
Monica
M
Novartis Vaccines, Siena, Italy.
Donati
Claudio
C
Muzzi
Alessandro
A
Masignani
Vega
V
Censini
Stefano
S
Hanage
William P
WP
Bishop
Cynthia J
CJ
Reis
Joice Neves
JN
Normark
Staffan
S
Henriques-Normark
Birgitta
B
Covacci
Antonello
A
Rappuoli
Rino
R
Barocchi
Michèle A
MA
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
D001426:Bacterial Proteins; D015534:Trans-Activators; C470697:rlrA protein, Streptococcus pneumoniae