title: Re-emergence of the type 1 pilus among Streptococcus pneumoniae isolates in Massachusetts, USA.
abstract: Pneumococcal type 1 pilus proteins have been proposed as potential vaccine candidates. Following conjugate pneumococcal vaccination, the prevalence of the pneumococcal type 1 pilus declined dramatically, a decline associated with the elimination of vaccine-type (VT) strains. Here we show that between 2004 and 2007, there has been a significant increase in pilus prevalence, now exceeding rates from the pre-conjugate vaccine era. This increase is primarily due to non-VT strains. These emerging piliated non-VT strains are mostly novel clones, with some exceptions. The rise in pilus type 1 frequency across multiple distinct genetic backgrounds suggests that the pilus may confer an intrinsic advantage.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA. gregev@hsph.harvard.edu
authors.forename: Gili
authors.initials: G
authors.lastname: Regev-Yochay
authors.forename: William P
authors.initials: WP
authors.lastname: Hanage
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Trzcinski
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Rifas-Shiman
authors.forename: Grace
authors.initials: G
authors.lastname: Lee
authors.forename: Andrew
authors.initials: A
authors.lastname: Bessolo
authors.forename: Susan S
authors.initials: SS
authors.lastname: Huang
authors.forename: Stephen I
authors.initials: SI
authors.lastname: Pelton
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: McAdam
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Finkelstein
authors.forename: Marc
authors.initials: M
authors.lastname: Lipsitch
authors.forename: Richard
authors.initials: R
authors.lastname: Malley
mesh_terms: D002353:Carrier State; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005260:Female; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D009305:Nasopharynx / Q000382:microbiology; D009876:Operon; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000737:chemistry* / Q000145:classification / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D022242:Pneumococcal Vaccines; D036781:Fimbriae Proteins