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Effectiveness of the probiotic Streptococcus salivarius K12 for the treatment and/or prevention of sore throat: a systematic review.

  • 2019-06
  • Clinical Microbiology and Infection 25(6)
    • C. Wilcox
    • C. Wilcox
    • B. Stuart
    • Hannah Leaver
    • M. Lown
    • M. Willcox
    • Michael Moore
    • P. Little


Background: Sore throat resulting from pharyngotonsillitis is one of the commonest reasons for primary care consultation and inappropriate antibiotic prescription and finding effective alternative treatments is important.

Objectives: To review the evidence for using the probiotic Streptococcus salivarius K12 (SsK12) for the prevention or treatment of pharyngotonsillitis.

Data sources: PubMed, Embase, CINAHL and Cochrane Library.

Study eligibility criteria: Randomized controlled trials (RCTs).

Participants: Adults or children.

Interventions: SsK12 as active treatment or prophylaxis, against pharyngotonsillitis.

Methods: Literature search.

Results: Four articles were identified (1846 participants). All were deemed to be of poor quality using the Cochrane risk-of-bias assessment. Two trials studied SsK12 prophylaxis for streptococcal pharyngitis (children without history of recurrence). One compared daily administration of SsK12 to no treatment over 6 months (n = 222, age 33-45 months), reporting significantly lower incidence in the SsK12 group (16.2% vs. 48.6%, p < 0.01), whereas another placebo-controlled RCT over four school terms (n = 1314, 5-14 years) found no significant difference (7.8% vs. 8.8%, p 0.34) with SsK12 (administered on school days). Another trial found daily SsK12 to significantly protect children (n = 250, 6-7 years) against chronic adenoiditis exacerbation over 3 months compared to no treatment (71.7% vs. 100%, p < 0.0001). The one placebo-controlled RCT in adults that studied the use of SsK12 for acute pharyngotonsillitis (concurrently with penicillin) showed no significant benefit. In all trials, SsK12 was safe and well tolerated.

Conclusions: SsK12 appears safe and well tolerated. However, further RCTs are required to establish its role as a prophylactic therapy, particularly among patients experiencing frequent exacerbations of pharyngitis. In the acute setting, SsK12 is unlikely to be effective if given concurrently with antibiotics; however, further RCTs should establish its role as an alternative to antibiotics in nonsevere cases or when prescribed after antibiotic therapy for the prevention of disease recurrence and/or secondary infection.

Keywords: Pharyngitis; Probiotics; S. salivariusK12; Sore throat; Streptococcus salivariusK12; Tonsillitis.

Research Insights

SupplementHealth OutcomeEffect TypeEffect Size
Streptococcus salivarius BLIS K12No Significant Benefit for Acute PharyngotonsillitisNeutral
Streptococcus salivarius BLIS K12No Significant Impact on Streptococcal PharyngitisNeutral
Streptococcus salivarius BLIS K12Reduced Exacerbation of Chronic AdenoiditisBeneficial
Streptococcus salivarius BLIS K12Reduced Incidence of Streptococcal PharyngitisBeneficial
Streptococcus salivarius K12Improved Effectiveness in Acute Pharyngotonsillitis TreatmentNeutral
Streptococcus salivarius K12Incidence of Streptococcal PharyngitisBeneficial
Streptococcus salivarius K12Reduced Exacerbation of Chronic AdenoiditisBeneficial

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