ORIGINAL: Assessment of the Initial Acquisition of Streptococcus mutans in Infants Born to Pregnant Women Attending the Lagos University Teaching Hospital

West Afr J Med. July 2025; 42(7): 531-541 PMID: 41370185

Abstract

Aim: Streptococcus mutans has been strongly associated with dental caries. The mother, the primary caregiver in the first year of life is the most significant source of the bacteria. The presence of S. mutans in infants from birth to 6 weeks of life was assessed.

Methodology: Prospective study of 24 women enrolled during their third trimester. Socio-demographic characteristics, oral hygiene, dietary practices and obstetric characteristics obtained using investigator-administered questionnaire. Saliva samples collection from neonates at birth and six weeks, investigated by cultural microbial analysis and polymerase chain reaction to detect S. mutans specific species genes.

Results: Total of 24 mother-child pairs assessed. Mothers mean age; 31.29 (+/- 4.6) years. Neonates' mean gestational age; 38.79 (+/-1.4) weeks, with 14 (58.3%) females and 10 (41.7) males. Microbiological culture analysis of the saliva sample of the neonates showed that 25% of the neonates had S. mutans at birth and 25% had it at 6 weeks post-delivery. Approximately 25% of salivary samples from the neonates showed S. mutans upon cultural analysis and correlated with the presence of the bacteria in 41.7% of the samples using Polymerase chain reaction. Streptococcus mutans detected at birth in 60% of neonates were identical to that of the mothers.

Conclusion: Maternal transmission is the primary source of S. mutans acquisition. Culture analysis of oral fluid revealed presence of viable and cultivable S. mutans in neonates asserting the acquisition of these species at birth and their presence before tooth eruption.