Related Experiment Video
Updated: Jan 14, 2026

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay
Published on: April 28, 2014
Oral Probiotic Containing Streptococcus salivarius K12 and Lactobacillus brevis CD2 for Preventing Bacterial
Jonathan R Lauxen1, Sidia M Callegari-Jacques2, Augusto S Mombelli3
1Postgraduate Program in Dentistry, School of Dentistry, University of Passo Fundo (UPF), Passo Fundo-RS, Brazil.
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.
Related Concept Videos
Pneumonia V: Nursing management and Prevention
The nurse must practice strict medical asepsis and adhere to infection control guidelines to minimize healthcare-associated infections.
Enhance airway patency
Position the patient correctly to facilitate drainage of the affected lung segments. Manual or mechanical percussion and vibration can also be employed....
Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
Pneumonia II: Pathophysiology
Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
Pneumonia III: Complications and Assessment

