TY - JOUR
T1 - Impact of the 13-valent pneumococcal conjugate vaccine on Streptococcus pneumoniae multiple serotype carriage
AU - Valente, Carina
AU - Hinds, Jason
AU - Gould, Katherine A.
AU - Pinto, Francisco R.
AU - de Lencastre, Hermínia
AU - Sá-Leão, Raquel
PY - 2016/7/25
Y1 - 2016/7/25
N2 - Introduction Pneumococcal multiple serotype carriage is important for evolution of the species and to understand how the pneumococcal population is changing with vaccination. We aimed to determine the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on multiple serotype carriage. Methods and materials Nasopharyngeal samples from fully vaccinated pneumococcal carriers (4 doses of PCV13, n = 141, aged 18–72 months) or from non-vaccinated pneumococcal carriers (0 doses of any PCV, n = 140, same age group) were analyzed. Multiple serotype carriage was evaluated by DNA hybridization with a molecular serotyping microarray that detects all known serotypes. Results Vaccinated children had a lower prevalence of multiple serotype carriage than the non-vaccinated group (20.6% vs 29.3%, p = 0.097), and a significantly lower proportion of PCV13 serotypes (6.4% vs 38.5%, p = 0.0001). PCV13 serotypes found among vaccinated children were mostly detected as a minor serotype in co-colonization with a more abundant non-vaccine serotype. Vaccinated children were colonized by a significantly higher proportion of commensal non-pneumococcal Streptococcus spp. (58.2% vs 42.8%, p = 0.012). In vaccinated children there were significantly less non-vaccine type (NVT) co-colonization events than expected based on the distribution of these serotypes in non-vaccinated children. Conclusions The results suggest that vaccinated children have lower pneumococcal multiple serotype carriage prevalence due to higher competitive abilities of non-vaccine serotypes expanding after PCV13 use. This might represent an additional benefit of PCV13, as decreased co-colonization rates translate into decreased opportunities for horizontal gene transfer and might have implications for the evolution and virulence of pneumococci.
AB - Introduction Pneumococcal multiple serotype carriage is important for evolution of the species and to understand how the pneumococcal population is changing with vaccination. We aimed to determine the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on multiple serotype carriage. Methods and materials Nasopharyngeal samples from fully vaccinated pneumococcal carriers (4 doses of PCV13, n = 141, aged 18–72 months) or from non-vaccinated pneumococcal carriers (0 doses of any PCV, n = 140, same age group) were analyzed. Multiple serotype carriage was evaluated by DNA hybridization with a molecular serotyping microarray that detects all known serotypes. Results Vaccinated children had a lower prevalence of multiple serotype carriage than the non-vaccinated group (20.6% vs 29.3%, p = 0.097), and a significantly lower proportion of PCV13 serotypes (6.4% vs 38.5%, p = 0.0001). PCV13 serotypes found among vaccinated children were mostly detected as a minor serotype in co-colonization with a more abundant non-vaccine serotype. Vaccinated children were colonized by a significantly higher proportion of commensal non-pneumococcal Streptococcus spp. (58.2% vs 42.8%, p = 0.012). In vaccinated children there were significantly less non-vaccine type (NVT) co-colonization events than expected based on the distribution of these serotypes in non-vaccinated children. Conclusions The results suggest that vaccinated children have lower pneumococcal multiple serotype carriage prevalence due to higher competitive abilities of non-vaccine serotypes expanding after PCV13 use. This might represent an additional benefit of PCV13, as decreased co-colonization rates translate into decreased opportunities for horizontal gene transfer and might have implications for the evolution and virulence of pneumococci.
KW - Co-colonization
KW - Microarray
KW - Multiple serotype carriage
KW - PCV13
KW - Pneumococcal conjugate vaccine
KW - Streptococcus pneumoniae
UR - http://www.scopus.com/inward/record.url?scp=84979233581&partnerID=8YFLogxK
U2 - 10.1016/j.vaccine.2016.06.017
DO - 10.1016/j.vaccine.2016.06.017
M3 - Article
AN - SCOPUS:84979233581
SN - 0264-410X
VL - 34
SP - 4072
EP - 4078
JO - Vaccine
JF - Vaccine
IS - 34
ER -