title: Molecular surveillance on Streptococcus pneumoniae carriage in non-elderly adults; little evidence for pneumococcal circulation independent from the reservoir in children.
abstract: Carriage of Streptococcus pneumoniae in adults is rarely detected by the gold standard culture method. With molecular tests of high sensitivity now available, we analysed upper respiratory tract samples collected during autumn/winter 2012/2013 from parents of PCV7-vaccinated infants and from childless adults, directly comparing culture and qPCR-based S. pneumoniae detection. As compared to the gold standard of testing nasopharyngeal swabs, qPCR-based analysis of oral samples significantly improved detection of pneumococcal carriage (5% versus 20%, p < 0.0001) with higher carriage rates in parents compared to childless adults (34% versus 7%; p < 0.001). Molecular methods also increased the number of serotype-carriage events detected with higher carriage frequencies of serotypes 3 and 7A/F and lower of serotypes 6C/D and 15A/B/C in parents compared to their infant children. We provide evidence that culture-based methods severely underestimate adult carriage rates and for the superiority of testing oral samples over nasopharyngeal swabs. The substantial circulation of pneumococci in parents is however, not representative for the entire adult population. While age-associated differences in serotype carriage suggests reservoirs outside infants as potential sources of vaccine-serotypes contributing to weakening of vaccine herd effects, we find no evidence for reservoirs in adults contributing to serotype replacement in carriage.
authors.affiliation: Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Wyllie
authors.affiliation: Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Lidewij W
authors.initials: LW
authors.lastname: Rümke
authors.affiliation: Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Kayleigh
authors.initials: K
authors.lastname: Arp
authors.affiliation: Spaarne Gasthuis Academy, Hoofddorp and Haarlem, The Netherlands.
authors.forename: Astrid A T M
authors.initials: AATM
authors.lastname: Bosch
authors.affiliation: Regional Laboratory of Public Health, Haarlem, The Netherlands.
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Bruin
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Nynke Y
authors.initials: NY
authors.lastname: Rots
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Alienke J
authors.initials: AJ
authors.lastname: Wijmenga-Monsuur
authors.affiliation: Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.|Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Elisabeth A M
authors.initials: EAM
authors.lastname: Sanders
authors.affiliation: Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Trzciński
mesh_terms: D000328:Adult; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004197:Disease Reservoirs / Q000382:microbiology* / Q000706:statistics & numerical data; D006801:Humans; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D010290:Parents; D011008:Pneumococcal Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D012703:Serotyping; D022541:Streptococcal Vaccines / Q000627:therapeutic use; D013296:Streptococcus pneumoniae / Q000145:classification / Q000235:genetics / Q000472:pathogenicity
chemical_list: D022541:Streptococcal Vaccines