Why parents should avoid transferring saliva into their baby's mouth - study

One will often see mothers who – when their baby throws its pacifier on the floor – pick it up and put it in her own mouth to “clean” it. Some parents also kiss their babies on the mouth or share the same cutlery or even a toothbrush in an emergency/ 

This is a terrible mistake. An adult’s mouth is full of a large variety of bacteria and fungi, including harmful pathogens like Candida albicans. 

A new study from the US and Kuwait has found that mothers with high levels of dental plaque are eight times more likely to transfer Candida albicans, which is involved in tooth decay and gum disease, to their babies, underlining the need for moms to keep their teeth clean.

Nisreen Al Jallad, Tong Tong Wu, and Jin Xiao from the University of Rochester in New York and Naemah Alkhars from Kuwait University have just published their findings in the journal PLOS One under the title “Multilocus sequence typing of oral isolates reveals high genetic relatedness of mother-child dyads in early life.” 

They wrote that Candida albicans is a pathogenic fungus recently recognized for its role in severe early childhood caries development. Its colonization in the mouth begins at birth, but the extent of the mother’s involvement in yeast transmission to their children has been unclear. 

How did the researchers come to the above conclusion?

Their study used a prospective mother-infant cohort to investigate the maternal contribution of C. albicans oral colonization in early life. Oral samples were collected from 160 mother-child pairs during pregnancy and from birth to two years of life. They used whole-genome sequencing to obtain the genetic information of C. albicans isolates and examined the genetic relatedness of C. albicans between mothers and their children.    

Although factors such as race, ethnicity, delivery method, and feeding behaviors did not show a significant connection with transmission from mother to baby, the mother’s oral hygiene status reflected by plaque index emerged as a significant factor.

Studies have reported that C. albicans can be detected in the saliva and dental plaque of individuals with dental caries and that its concentration is higher in those with active caries than in those without, the authors wrote. In addition, the fungus has been shown to form biofilms on the surface of teeth that can promote the retention of other microorganisms and contribute to the development of cavities.