University of Oulu

Sarlin, Suvi MD*,†; Tejesvi, Mysore V. PhD‡; Turunen, Jenni MSc‡; Vänni, Petri MSc‡; Pokka, Tytti MSc*,†; Renko, Marjo MD, PhD†,§; Tapiainen, Terhi MD, PhD*,†,¶ Impact of Streptococcus salivarius K12 on Nasopharyngeal and Saliva Microbiome: A Randomized Controlled Trial, The Pediatric Infectious Disease Journal: May 2021 - Volume 40 - Issue 5 - p 394-402, doi: 10.1097/INF.0000000000003016

Impact of Streptococcus salivarius K12 on nasopharyngeal and saliva microbiome : a randomized controlled trial

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Author: Sarlin, Suvi1; Tejesvi, Mysore V.2; Turunen, Jenni2;
Organizations: 1PEDEGO Research Unit and Medical Research Center Oulu
2Genetics and Physiology, Faculty of Science, University of Oulu
3Department of Pediatrics and Adolescent Medicine, Kuopio University Hospital
4Biocenter Oulu, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: Wolters Kluwer, 2021
Publish Date: 2021-05-10


Background: Probiotic lactobacilli have been ineffective in preventing acute otitis media. In contrast to lactobacilli, alpha-hemolytic streptococci belong to the core microbiome of nasopharynx.

Methods: We investigated the effects of Streptococcus salivarius K12 probiotic on the saliva and nasopharyngeal microbiome in 121 children attending daycare. Children were randomly allocated to receive oral K12 product for 1 month or no treatment. We obtained saliva and nasopharyngeal samples at study entry, at 1 and 2 months. The next-generation sequencing of the bacterial 16S gene was performed.

Results: After the intervention, the diversity of saliva or nasopharyngeal microbiome did not differ between groups. The proportion of children with any otopathogen did not differ between the groups. At 1 month, the abundance of otopathogens in nasopharynx was lower in K12 group compared with that in control children (34% vs. 55%, P = 0.037). When we compared each otopathogen separately, Moraxella was the only group lower in the treatment group. We could not verify the reduction of Moraxella when an alternative Human Oral Microbiome Database taxonomy database was used. In children receiving K12 product, the mean abundance of S. salivarius was greater in saliva after the intervention (0.9% vs. 2.0%, P = 0.009).

Conclusions: The use of S. salivarius K12 probiotic appeared to be safe because it did not disrupt the normal microbiome in young children. Even though a short-term colonization of S. salivarius was observed in the saliva, the impact of S. salivarius K12 probiotic on the otopathogens in nasopharyngeal microbiome remained uncertain.

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Series: Pediatric infectious disease journal
ISSN: 0891-3668
ISSN-E: 1532-0987
ISSN-L: 0891-3668
Volume: 40
Issue: 5
Pages: 394 - 402
DOI: 10.1097/INF.0000000000003016
Type of Publication: A1 Journal article – refereed
Field of Science: 3123 Gynaecology and paediatrics
3141 Health care science
Funding: The study was financially supported by the Finnish Pediatric Research Foundation, Academy of Finland, Yrjö Jahnsson Foundation, Päivikki and Sakari Sohlberg Foundation, Finnish Medical Foundation, University of Oulu Health and Biosciences Doctoral Programme and Alma and K.A. Snellman Foundation, Finland. Study products were donated by GutGuide Ltd., Finland, and Bluestone Pharma (Rathausstr. 14, CH-6340 Baar, Switzerland).
Copyright information: © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CC BY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.