Streptococcus pneumoniae oropharyngeal colonization in school-age children and adolescents with type 1 diabetes mellitus: Impact of the heptavalent pneumococcal conjugate vaccine

Abstract

This study evaluated Streptococcus pneumoniae colonization in children and adolescents with type 1 diabetes mellitus (DM1) to investigate the theoretical risk of invasive pneumococcal disease (IPD) in these patients and the potential protective efficacy of pneumococcal conjugate vaccines (PCVs). An oropharyngeal swab was obtained from 299 patients aged 6–17 y with DM1 who were enrolled during routine clinical visits. DNA from swabs was analyzed for S. pneumoniae using real-time polymerase chain reaction. S. pneumoniae was identified in the swabs of 148 subjects (49.8%). Colonization was strictly age-related and declined significantly in the group aged ≥15 years (odds ratio [OR] 0.28; 95% confidence interval [CI], 0.14–0.57). Carriage was also significantly influenced by sex (lower in females: OR 0.56; 95% CI, 0.35–0.91), ethnicity (less common among non-Caucasians: OR 0.34; 95% CI, 0.13–0.89), parental smoking habit (more frequent among children with at least one smoker between parents: OR 1.76; 95% CI, 0.90–2.07), and the administration of antibiotic therapy in the previous 3 months (less frequent among patients who received antibiotics: OR 0.21; 95% CI, 0.07–0.62). Multivariate analyses of the entire study population showed no association between carriage and PCV7 vaccination status. Serotypes 19F, 9V, and 4 were the most frequently identified serotypes. In conclusion, school-age children and adolescents with DM1 are frequently colonized by S. pneumoniae, and protection against pneumococcal carriage following infant and toddler vaccination was not effective after several years. Together with the need to increase vaccine uptake in all the children aged <2 years, these results suggest that PCV booster doses are needed in DM1 patients to maintain the protection offered by these vaccinations.

Keywords:

• children
• diabetes
• diabetes mellitus
• pediatrics
• pneumococcal infection
• pneumococcal conjugate vaccine
• pneumococcal vaccine
• Streptococcus pneumoniae
• type 1 diabetes mellitus

Disclosure of Potential Conflicts Of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We thank all of the participants in the Italian Pneumococcal Study Group on Diabetes: Susanna Esposito, Nicola Principi, Luca Ruggiero, Leonardo Terranova, Alberto Zampiero, Valentina Montinaro, Valentina Ierardi, Monia Gambino (Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy); Lorenzo Iughetti, Viviana Patianna (Pediatric Clinic, University of Modena and Reggio Emilia, Modena, Italy); Marco Cappa, Maria Cristina Matteoli, Patrizia Patera, Paolo Ciampalini, Riccardo Schiaffini, (Unit of Endocrinology and Diabetic Bambino Gesù Children's Hospital IRCCS, Rome, Italy); Claudio Maffeis, Marco Marigliano, Anita Morandi (Regional Center for Pediatric Diabetes, Clinical Nutrition and Obesity, ULSS 20, and University of Verona, Verona, Italy); Franco Chiarelli, Paola Cipriano (Department of Pediatrics, University of Cheti, Chieti, Italy); Gianni Bona, Silvia Parlamento, Erica Pozzi (Division of Pediatrics, Department of Health Sciences, Università del Piemonte Orientale “Amedeo Avogadro,” Novara, Italy).

Funding

This study was supported by a grant from the Italian Ministry of Health (Bando Giovani Ricercatori 2009) and an unrestricted educational grant from Pfizer International to the Italian Society for Pediatric Infectious Diseases (SITIP).