Influence of maternal oral microbiome on newborn oral microbiome in healthy pregnancies

BACKGROUND

Periodontal disease and its bacteria can be responsible for pregnancy complications and transmission of periodontal bacteria from mother to newborn.

METHODS

A salivary swab to 60 healthy, full-term newborns and their mothers was taken immediately after birth. The test was performed with Real Time PCR method to evaluate the expression of the gene through DNA amplification. The species considered were: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum ssp.

RESULTS

The newborn oral microbiome was composed primarily by saprophytes (98.38 + 4.88%), just like the mothers (98.8 + 3.69%). There was a statistically significant difference of the total microbiological density in newborns and mothers (p = 0.0001). Maternal and neonatal oral microbiome had a correlated total microbiological density only in 33.3% (N = 20/60) of cases. The analysis of the oral microbiome showed a pathological composition only in 12/60 babies (20%). The most frequent detected specie in newborns was Fusobacterium nucleatum (9/12 babies, 75%), as well as for the mothers (53.3%). However, the pathogen was present both in baby and his mother only in 3 dyads. Porphyromonas gingivalis showed the highest association mother-baby (4/12 dyads, 33%). Porphyromonas gingivalis was the pathogen with the highest bacterial load in the 12 mothers. We found a statistically significant difference in the total load of Porphyromonas gingivalis in mothers and babies (p = 0.02).

CONCLUSIONS

There was a statistically significant difference in the richness of the microbiome from newborns and mothers. Even comparing the microbiological density in the oral cavity of the individual mother-child pairs, we did not find a significant concordance. These results seem to suggest a low influence of maternal oral microbiome on the richness of the oral neonatal one. We didn't find mother-child concordance (p = 0.0001) in the presence of pathogenic periodontal micro-organisms. Fusobacterium nucleatum was the most frequent specie detected. Porphyromonas gingivalis instead was the bacteria with the higher possibility of transmission. In conclusion in our study maternal oral health doesn't affect healthy, full-term newborns' oral microbiome. Further studies are needed to understand the maternal influence on newborn's oral microbiome and its effects on babies long-term health.

Hashimoto's Thyroiditis

Hashimoto's Thyroiditis (HT) is the most common cause of thyroid diseases in children and adolescents and it is also the most common cause of acquired hypothyroidism with or without goiter. The linkage between HT and some HLA genes has been reported and a genetic predisposition to thyroid autoimmunity is suggested by observations in twins. There is no direct evidence that infections cause HT in humans, while iodine and iodine containing drugs can precipitate HT in susceptible populations. There is an infiltration of lymphocytes and plasma cells between the follicles followed by their atrophy. The clinical course is variable and spontaneous remission may occur in adolescence. Goiter, menstrual disorders, short stature, constipation, nervousness and exophthalmos have been reported as the most recurrent clinical features of HT. Nevertheless we studied 33 patients with HT, 22 girls and 11 boys aged 4.9-19 years and most of them were euthyroid clinically. Hashimoto thyroiditis is often associated with type 1 diabetes and other autoimmune disorders such as coeliac disease, type 2 and type 3 polyglandular autoimmune disorders. Girls with Turner syndrome may develop HT. Patients with HT have positive antibodies to thyroglobulin and/or to thyroperoxidase in blood. Thyroid function could be normal or abnormal (overt hypothyroidism, subclinical hypothyroidism and hyperthyroidism). Abnormal ultrasound patterns may be present in patients with HT disease as diffuse hypoechogenicity and pseudonodules. L-thyroxine therapy is indicated in HT with hypothyroidism, but periodic re-evaluations are required because HT could be a self-limited disorder in some cases.