Epidemiological and molecular characterization of Streptococcus pneumoniae carriage strains in pre-school children in Arkhangelsk, northern European Russia, prior to the introduction of conjugate pneumococcal vaccines

V. Vorobieva*, A. S. Furberg, H. C. Slotved, T. Bazhukova, B. Haldorsen, D. A. Caugant, A. Sundsfjord, P. Valentiner-Branth, G. S. Simonsen

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review


Background: The 13-valent Pneumococcal Conjugate Vaccine (PCV-13) was introduced in the National Immunization Programme (NIP) schedule in Russia in March 2014. Previously, the 7-valent Pneumococcal Conjugate Vaccine (PCV-7) was marketed in Russia in 2009 but has never been offered for mass vaccination. A carriage study was performed among children in Arkhangelsk in 2006. The objective was to determine the prevalence of carriage, serotype distribution, antimicrobial susceptibility and the molecular structure of Streptococcus pneumoniae strains before marketing and introduction of PCV-13. Methods: A cross-sectional study was conducted on a cluster-randomized sample of children and a self-administrated questionnaire for parents/guardians. Nasopharyngeal samples were collected from 438 children younger than 7 years attending nurseries and kindergartens in the Arkhangelsk region, Russia. Detailed demographic data, as well as information about the child's health, traveling, exposure to antimicrobials within the last 3 months and anthropometric measurements were collected for all study subjects. Variables extracted from the questionnaire were analysed using statistic regression models to estimate the risk of carriage. All pneumococcal isolates were examined with susceptibility testing, serotyping and multilocus sequence typing. Results: The overall prevalence of asymptomatic carriage was high and peaking at 36 months with a rate of 57%. PCV-13 covered 67.3% of the detected strains. High rates of non-susceptibility to penicillin, macrolides and multidrug resistance were associated with specific vaccine serotypes, pandemic clones, and local sequence types. Nine percent of isolates represented three globally disseminated disease-associated pandemic clones; penicillin- A nd macrolide-resistant clones NorwayNT-42 and Poland6B-20, as well as penicillin- A nd macrolide-susceptible clone Netherlands3-31. A high level of antimicrobial consumption was noted by the study. According to the parent's reports, 89.5% of the children used at least one antimicrobial regime since birth. None of the hypothesised predictors of S. pneumoniae carriage were statistically significant in univariable and multivariable logistic models. Conclusions: The study identified a high coverage of the PCV-13-vaccine, but serotype replacement and expansion of globally disseminated disease-associated clones with non-vaccine serotypes may be expected. Further surveillance of antimicrobial resistance and serotype distribution is therefore required.

Original languageEnglish
Article number279
JournalBMC Infectious Diseases
Issue number1
Publication statusPublished - 15 Apr 2020
Externally publishedYes

Bibliographical note

Funding Information:
VVSJ was granted by the Quota Scheme of the Norwegian State Education Loan Fund. HCS is involved with projects supported by Pfizer. All other authors were funded by their individual departments. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Funding Information:
Hans-Christian Slotved is involved with projects supported by Pfizer. All other authors had declare that they have no competing interests.

Publisher Copyright:
© 2020 The Author(s).


  • Multidrug-resistance
  • Pandemic clones
  • PCV-13-vaccine
  • Russia
  • Sequencing
  • Serotyping

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