Characterization of the unique oral microbiome of children harboring Helicobacter pylori in the oral cavity.

Objective: Helicobacter pylori infection is acquired in childhood via the oral cavity, although its relationship with the characteristics of the oral microbiome has not been elucidated. In this study, we performed comprehensive analysis of the oral microbiome in children and adults with or without H. pylori in the oral cavity. Methods: Bacterial DNA was extracted from 41 adult and 21 child saliva specimens, and H. pylori was detected using PCR. 16S rRNA gene amplification was performed for next-generation sequencing. Bioinformatic analyses were conducted using Quantitative Insights into Microbial Ecology 2 (QIIME 2). Results: Faith's phylogenetic diversity analysis showed a significant difference between H. pylori-negative adult and child specimens in terms of α-diversity (p < 0.05), while no significant difference was observed between H. pylori-positive adult and child specimens. There was also a significant difference in ß-diversity between H. pylori-positive and negative child specimens (p < 0.05). Taxonomic analysis at the genus level revealed that Porphyromonas was the only bacterium that was significantly more abundant in both H. pylori-positive adults and children than in corresponding negative specimens (p < 0.01 and p < 0.05, respectively). Conclusion: These results suggest unique oral microbiome characteristics in children with H. pylori infection in the oral cavity.

Different Dental Manifestations in Sisters with the Same ALPL Gene Mutation: A Report of Two Cases.

Hypophosphatasia (HPP) is an inherited disease caused by mutation of the alkaline phosphatase (ALPL) gene in an autosomal dominant or an autosomal recessive manner. The main symptoms of HPP are bone hypomineralization and early exfoliation of the primary teeth. Some of the mutations identified in autosomal dominant families are reported to have dominant negative effects. In addition, the penetrance can vary among patients with the same variant even within the same family, resulting in various phenotypes of systemic symptoms. However, differences in dental symptoms between patients with HPP and carriers with the same ALPL variant have not been reported. Herein, we report on two sisters who had the same heterozygous ALPL variant with dominant negative effects. The older sister had bone and dental symptoms and was diagnosed with childhood HPP. In contrast, the younger sister was a carrier with no bone and dental symptoms. It can be inferred that this phenomenon was caused by the difference in penetrance. This case revealed that carriers with the ALPL mutation may have no dental symptoms characteristic of HPP. Because HPP is sometimes progressive, it is very important to carefully monitor carriers to detect the possible onset of dental and systemic symptoms.

Dental Manifestations Leading to the Diagnosis of Hypophosphatasia in Two Children.

Hypophosphatasia (HPP) is an inherited bone disease caused by mutation of the alkaline phosphatase, biomineralization associated (ALPL) gene and is characterized by bone hypomineralization and/or early exfoliation of primary teeth. Dental manifestations can lead to the diagnosis of milder types of HPP. The purpose of this paper is to report the case of two patients with growth and development problems who were referred to a dental clinic due to early exfoliation of primary teeth and were subsequently diagnosed with childhood HPP with bone symptoms. Early diagnosis of HPP and management of growth and development are important, as HPP is a progressive disease. When dentists detect early exfoliation of the mandibular incisors before four years of age, they should refer the patient for investigation of HPP. Growth and development should be closely monitored in patients with early primary tooth exfoliation.

Contribution of Streptococcus mutans to Helicobacter pylori colonisation in oral cavity and gastric tissue.

Helicobacter pylori is presumed to infect gastric tissue via the oral cavity in childhood, whereas risk factors for H. pylori infection in the oral cavity are unknown. In this study, we analysed the effects of Streptococcus mutans, a major cariogenic bacterial species, on H. pylori colonisation in the oral cavity, as well as gastric tissue. Rats in the weaning period were infected with S. mutans in the oral cavity, then fed a caries-inducing diet to facilitate S. mutans colonisation. One month after S. mutans infection, rats were infected with H. pylori in the oral cavity; rats were then euthanised at 1 month after H. pylori infection. H. pylori was detected in the oral cavities of rats infected with both S. mutans and H. pylori, but not in rats infected with H. pylori alone. In addition, H. pylori colonisation in the gastric tissue and typical gastrointestinal damage were observed in rats infected with both S. mutans and H. pylori. When H. pylori was co-cultured with in vitro biofilm formed by S. mutans, a large number of H. pylori bacteria invaded the biofilm formed by S. mutans. Our results suggest that S. mutans is involved in the establishment of H. pylori infection.

Distribution of Helicobacter pylori and Periodontopathic Bacterial Species in the Oral Cavity.

The oral cavity may serve as a reservoir of Helicobacter pylori. However, the factors required for H. pylori colonization are unknown. Here, we analyzed the relationship between the presence of H. pylori in the oral cavity and that of major periodontopathic bacterial species. Nested PCR was performed to detect H. pylori and these bacterial species in specimens of saliva, dental plaque, and dental pulp of 39 subjects. H. pylori was detected in seven dental plaque samples (17.9%), two saliva specimens (5.1%), and one dental pulp (2.6%) specimen. The periodontal pockets around the teeth, from which dental plaque specimens were collected, were significantly deeper in H. pylori-positive than H. pylori-negative subjects (p < 0.05). Furthermore, Porphyromonas gingivalis, a major periodontopathic pathogen, was detected at a significantly higher frequency in H. pylori-positive than in H. pylori-negative dental plaque specimens (p < 0.05). The distribution of genes encoding fimbriae (fimA), involved in the periodontal pathogenicity of P. gingivalis, differed between H. pylori-positive and H. pylori-negative subjects. We conclude that H. pylori can be present in the oral cavity along with specific periodontopathic bacterial species, although its interaction with these bacteria is not clear.

Potential involvement of Helicobacter pylori from oral specimens in overweight body-mass index.

The bacterium Helicobacter pylori was originally classified in the Campylobacter genus, which contains major periodontopathic bacterial species, and H. pylori DNA has been found in the oral cavity. Although many studies show an association between the presence of periodontal bacteria and an overweight body-mass index (BMI; >25 kg/m2), the relationship between body weight and the presence of H. pylori in the oral cavity has not been demonstrated. Herein, we analysed the relationship between H. pylori in the oral cavity and systemic conditions, including the overweight BMI. Saliva specimens and extracted teeth were obtained from 87 subjects; the distribution of H. pylori among these specimens was analysed with the polymerase chain reaction. Subjects with an overweight BMI exhibited significantly higher detection rates of H. pylori in saliva, compared with non-overweight subjects (BMI <25 kg/m2) (P < 0.05). A clinical history of digestive diseases was not associated with the presence of H. pylori in overweight subjects, whereas subjects with both severe dental caries and an overweight BMI showed a higher detection rate of H. pylori in saliva specimens, compared with other groups. These results suggest that the detection of H. pylori in the oral cavity could be associated with the overweight BMI, which was predominant among subjects with severe dental caries.

Identification and molecular characterization of Porphyromonas gulae fimA types among cat isolates.

Porphyromonas gulae, a Gram-negative black-pigmented anaerobe, is one of several major periodontal pathogens of animals. P. gulae isolates from dogs have been classified into three genotypes based on a 41-kDa filamentous appendage (FimA) on the cell surface, which is closely related to virulence in periodontal disease. However, other specific bacterial virulence factors contributing to the aggravation of periodontal disease in cats remain elusive. In the present study, we assessed FimA diversity in P. gulae isolates from cats and examined whether this diversity influenced periodontal condition. The putative amino acid sequences of FimA from 15 P. gulae isolates from 13 cats were classified into three genotypes (types A, B, and C), which showed 95-100% identity and similarity to the fimA types in dogs. The type C isolate showed greater adhesion and invasion properties in periodontal ligament fibroblasts as well as stronger inhibition of scratch closure of the cells compared with type A and B isolates. Next, a PCR-based method for identification of fimA genotype was developed and used to analyze 99 oral swab specimens from cats. High fimA type A detection rates were observed regardless of the periodontal condition, whereas types B and C were frequently detected from subjects with moderate and severe periodontitis, respectively. These results suggest that P. gulae isolates from cats can be classified into three types based on fimA genotype, which may be closely related to virulence in periodontitis.

Comparison of oral flora before and after triple therapy for Helicobacter pylori eradication in patient with gastric disease.

The oral cavity is recognized as a major route for infection by Helicobacter pylori, which colonizes the gastric mucosa. Therapeutic options for elimination in patients with digestive disease have been established, though whether antibiotics are effective for H. pylori harbored in the oral cavity as well as oral commensal bacteria remain unknown. A 29-year-old woman visited a gastrointestinal clinic with a chief complaint of stomach ache. Gastroscopy and urine test findings for H. pylori IgG led to a definitive diagnosis of goose bumps gastritis induced by bacteria in the stomach, and triple therapy for H. pylori eradication was administered. Oral samples were obtained 10 times at a dental hospital clinic from 1 week before until 6 months after starting triple therapy. Nested PCR amplifying the ureA gene and PCR assays using species-specific primer sets were performed to detect H. pylori and major oral commensal bacterial species, respectively, in those samples. Bacterial DNA encoding the ureA gene of H. pylori in oral specimens was detected prior to starting therapy, which was then reduced during and not detected after finishing treatment. Although the populations of major oral pathogenic bacteria, such as periodontopathic and oral streptococcal species, were drastically reduced during triple therapy, most had recovered within approximately 1 week after ending treatment. These results suggest that a conventional triple therapy approach for eradication of H. pylori in cases of digestive disease is effective for elimination of the bacterium from the oral cavity. On the other hand, after finishing such therapy, the oral flora composition is not drastically changed.