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Oral Probiotic Containing Streptococcus salivarius K12 and Lactobacillus brevis CD2 for Preventing Bacterial Pneumonia in Severe COVID-19: Randomized Clinical Trial.

  • 2025-11-12
  • The journal of contemporary dental practice 26(10)
    • Jonathan R Lauxen
    • Sidia M Callegari-Jacques
    • Augusto S Mombelli
    • Amanda Prando
    • Tiago T Simon
    • Fernando Fornari

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 60
Population
60 patients with severe COVID-19
Methods
randomized, placebo-controlled trial, 7-day course of oral gel containing S. salivarius K12 (2 billion CFU) and L. brevis CD2 (4 billion CFU) every 8 hours, or placebo, starting on the first ICU day; gel applications performed by a dentist
Blinding
Double-blind
Duration
7 days
Funding
Unclear

Aims

To assess the effect of dental application of oral probiotics containing Streptococcus salivarius K12 and Lactobacillus brevis CD2 on preventing secondary bacterial pneumonia in patients with severe COVID-19.

Materials and methods

In this randomized, placebo-controlled trial, 60 patients with severe COVID-19 were randomly assigned to receive a 7-day course of oral gel containing S. salivarius K12 (2 billion colony-forming units) and L. brevis CD2 (4 billion colony-forming units) every 8 hours, or placebo, starting on the first intensive care unit (ICU) day. Gel applications were performed by a dentist. The primary outcome was bacterial pneumonia, whereas the secondary outcomes were survival and the 14-day illness-severity status.

Results

Fifty patients completed the 7-day experiment. In which, 26 patients received probiotics (mean age: 58.7 years old, 81% men) and 24 patients received a placebo (60.5 years old, 71% men). The incidence of secondary bacterial pneumonia was 35% for probiotics and 54% for placebo [relative risk: 0.64 (95% CI: 0.34-1.22)]. Compared with placebo, patients treated with probiotics showed similar rates of ICU death [hazard ratio: 1.37 (95% CI: 0.56-3.35)]. The 14-day illness-severity status did not differ between groups.

Conclusion

In this phase II trial of patients with severe COVID-19, oral probiotics containing S. salivarius K12 and L. brevis CD2 did not prevent secondary bacterial pneumonia.

Clinical significance

Intensive care unit patients with COVID-19 are prone to secondary bacterial pneumonia. Probiotics against oral pathogens might prevent lung colonization and avoid pneumonia. How to cite this article: Lauxen JR, Callegari-Jacques SM, Mombelli AS, et al. Oral Probiotic Containing Streptococcus salivarius K12 and Lactobacillus brevis CD2 for Preventing Bacterial Pneumonia in Severe COVID-19: Randomized Clinical Trial. J Contemp Dent Pract 2025;26(10):931-937.

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