Viable Helicobacter pylori was successfully cultivated from the root canals of 28 out of 170 endodontically infected primary teeth, according to a study conducted at the Department of Paediatric Dentistry and Primary Prevention at the University Hospital of Leipzig from July 2022 to August 2023.
The study investigated the presence and viability of Helicobacter pylori in the oral cavity, specifically within the root canals of endodontically infected primary teeth in children. The research involved 54 children (30 boys and 24 girls with a mean age of 6.22 years) and analyzed a total of 170 extracted teeth.
The researchers aimed to determine whether H. pylori, a bacterium known to colonize the human stomach, could survive and grow in the oral cavity, particularly in the root canals of decayed teeth. The study employed several methods to identify viable H. pylori, including selective growth techniques, PCR for gene detection, field-emission scanning electron microscopy, and protein expression analysis.
PCR analysis revealed H. pylori DNA in 32 root canal samples and 5 plaque samples. However, live bacteria were successfully cultivated from only 28 root canal samples, corresponding to 16.5% of the total teeth analyzed. No viable H. pylori was cultured from plaque samples. The isolates from the root canals were confirmed as H. pylori through gene sequencing of the vacA, cagA, and htrA genes. Notably, eight strains possessed a 171L-type HtrA variant, which has been associated with increased risk of gastric cancer development.
Phylogenetic analysis of the htrA gene showed that the isolates were genetically related to other H. pylori strains from the European population. Additionally, Western blotting confirmed the presence of major virulence factors, including urease, VacA, and CagA.
Published in Cell Communication and Signaling, the study demonstrated that the isolated strains induced typical H. pylori phenotypes when used to infect human gastric epithelial cells, including cell vacuolization and elongation. These phenotypes were associated with the presence of the s1/m1 allele of VacA and CagA-mediated signaling. Furthermore, infection with the strains activated NF-κB and β-catenin signaling pathways, consistent with the behavior of virulent H. pylori strains.
The research concludes that the microaerobic environment in root canals may represent a protected and transient reservoir for viable H. pylori, potentially contributing to reinfection or transmission.
Full disclosures can be found in the published study.
