Serotype distribution and antimicrobial susceptibilities of nasopharyngeal isolates of Streptococcus pneumoniae from healthy children in the 13-valent pneumococcal conjugate vaccine era

Gianvincenzo Zuccotti, Chiara Mameli, Laura Daprai, Maria Laura Garlaschi, Dario Dilillo, Giorgio Bedogni, Marino Faccini, Maria Gramegna, Erminio Torresani, Ballerini Emanuela, Benincaso Annarita, Bonvissuto Milena, Bricalli Dorella, Brioschi Manuela, Calloni Cinzia Simona, Camiletti Marina Irene, Colella Giacomo, De Angelis Laura, Decarlis Silvia, Di Nello FrancescaDozzi Massimiliano, Galli Erica, Gandini Vera, Giuliani Maria Grazia, Laviola Franca, Loda Barbara, Macedoni Maddalena, Mazzucchi Elisabetta, Metta Maria Gabriella, Moscatiello Anna, Nannini Pilar, Petruzzi Mariangela, Picicco Damiano, Picciotti Michela, Pisanelli Stefania, Porta Norberto, Ramponi Giulia, Redaelli Francesca, Rubini Riccardo, Sala Natascia, Saitta Vincenzo, Scelza Giuseppina, Tiso Rosa Maria, Tomasetto Mariangela, Torcoletti Matteo, Travaini Marta, Valentini Maurizio, Vessia Chiara

Research output: Contribution to journalArticlepeer-review

Abstract

Few epidemiological data are available since the introduction of 13-valent pneumococcal vaccine (PCV13) in 2010. We conducted a cross-sectional study to estimate the prevalence of Streptococcus pneumoniae (SP) nasopharyngeal carriage in healthy Italian infants and young children and to evaluate the impact of PCV13 on pneumococcal colonization. In the trimester September-December 2011 nasopharyngeal swabs were collected from healthy children aged 3-59 months presenting for routine well careat 16 primary care pediatricians in Milan.SP carriage isolates were serotyped and tested for antimicrobial resistance using EUCAST breakpoints. Among 1250 enrolled children, 618 had received at least 1 dose of PCV13, 292 at least 1 dose of PCV7, 94 a combination of the two vaccines and 246 were not vaccinated. The prevalence of SP carriage was 27% (95% confidence interval [CI] 25-30).At multivariable analysis, age. ≥. 25 months (prevalence ratio [PR]. = 0.74) and use of antibiotics in the previous 3 months (PR. = 0.67) were associated with lower SP carriage prevalence. Having siblings (PR. = 1.79 for 1 sibling and PR. = 2.23 for ≥2 siblings), day-care attendance (PR. = 2.27) and respiratory tract infections in the previous 3 months (PR. = 1.39) were associated with higher SP carriage prevalence.The immunization status for SP was not associated with SP carriage at univariable or at multivariable analysis.The most common carriage isolates were 6C, 19A and 23A. The prevalence of the six additional PCV13 serotypes carriage in children appropriately vaccinated with PCV13 was lower than in children appropriately vaccinated with PCV7 (0 vs. 0.060); the greater reduction in prevalence of carriage was observed for serotype 19A (0 vs. 0.041). Serotype 6C was the most common drug-resistant serotype (17.2%).Further epidemiological studies are needed to assess changes in circulating SP serotypes following the large-scale introduction of PCV13.

Original languageEnglish
Pages (from-to)527-534
Number of pages8
JournalVaccine
Volume32
Issue number5
DOIs
Publication statusPublished - Jan 23 2014

Keywords

  • 13-Valent pneumococcal conjugate vaccine
  • Children
  • Pneumococcal nasopharyngeal carriage
  • Streptococcus pneumoniae

ASJC Scopus subject areas

  • Immunology and Microbiology(all)
  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • veterinary(all)
  • Molecular Medicine

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