title: Vaccine escape of piliated Streptococcus pneumoniae strains.
abstract: Type1-pilus proteins were suggested as targets of future protein-based vaccines. Here we studied the effect of pneumococcal-conjugate vaccine (PCV7) implementation on the prevalence of piliated strains in a unique study setting which controls for typical confounders; the Palestinian-Israeli Collaborative Research (PICR).
  
  
  
  Annual cross-sectional surveys of pneumococcal carriage were performed during 2009-2011 among two closely related population that live under different health policies (a) Palestinian-Authority (PA) (n=1773), where PCV7 was not yet introduced (b) East-Jerusalem (EJ) (n=983) where PCV7 was rapidly implemented. Clinical data were collected, pneumococci identified and characterized and the presence of Type1-pilus genes was determined by rrgC PCR.
  
  
  
  Following PCV7 implementation in EJ, overall carriage prevalence did not change (∼30%), but VT7 strains decreased from 61.5% to 33.8%. While prevalence of non-piliated-VT7 isolates decreased from 37% to 10%, p<0.001, the prevalence of piliated-VT7 strains persisted ∼25%. Additionally, piliated non-VT13 strains emerged (1-15%, p<0.001). These changes were not observed in PA. These dynamics were independent of the bacteria's resistance pattern.
  
  
  
  A differential effect of PCV7 was observed with a relative resistance of piliated strains to the vaccine. This suggests that Type1-pilus confers an intrinsic advantage for colonization and may be an attractive vaccine target.
authors.affiliation: Infectious Dis. Unit, Sheba Med Ctr, Ramat-Gan, Israel; Section of Infectious Dis. Epidemiology, Gertner Institute for Epidemiology Research, Ramat-Gan, Israel. Electronic address: gili.regev.y@gmail.com.
authors.forename: Gili
authors.initials: G
authors.lastname: Regev-Yochay
authors.affiliation: Infectious Dis. Unit, Sheba Med Ctr, Ramat-Gan, Israel.
authors.forename: Hanaa
authors.initials: H
authors.lastname: Jaber
authors.affiliation: Private Clinic, Nabulus, Palestine.
authors.forename: Ayob
authors.initials: A
authors.lastname: Hamdan
authors.affiliation: Maccabi Healthcare Services, Jerusalem-Hashfela District, Israel; Hadassah University Medical Ctr, Jerusaelm, Israel.
authors.forename: Muhannad
authors.initials: M
authors.lastname: Daana
authors.affiliation: Maccabi Healthcare Services, Jerusalem-Hashfela District, Israel.
authors.forename: Hanan
authors.initials: H
authors.lastname: Nammouz
authors.affiliation: Private Clinic, Ramallah, Palestine.
authors.forename: Amin
authors.initials: A
authors.lastname: Thalji
authors.affiliation: Private Clinic, Bethlehem, Palestine.
authors.forename: Fuad
authors.initials: F
authors.lastname: Jaar
authors.affiliation: Al-Quds Nutrition and Health Research Institute, Al-Quds University, Abu-Dis, Palestine.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Abdeen
authors.affiliation: Section of Infectious Dis. Epidemiology, Gertner Institute for Epidemiology Research, Ramat-Gan, Israel.
authors.forename: Carmit
authors.initials: C
authors.lastname: Rubin
authors.affiliation: The Biostatistics Unit, Gertner Institute for Epidemiology Research, Ramat-Gan, Israel.
authors.forename: Amit
authors.initials: A
authors.lastname: Huppert
authors.affiliation: Maccabi Healthcare Services, Jerusalem-Hashfela District, Israel.
authors.forename: Meir
authors.initials: M
authors.lastname: Raz
authors.affiliation: Infectious Dis. Unit, Sheba Med Ctr, Ramat-Gan, Israel.
authors.forename: Galia
authors.initials: G
authors.lastname: Rahav
mesh_terms: D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D036781:Fimbriae Proteins / Q000235:genetics*; D006291:Health Policy; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000276:immunology*; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007557:Israel / Q000453:epidemiology; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D015995:Prevalence; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification*
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D036781:Fimbriae Proteins
keywords: PCV7 effects; Pilus type-1; Pneumococcal vaccines; Population-based study