The Prevalence of Streptococcus Mutans with Different ABO Blood Groups Among Healthy College Students

This study was conducted to determine the correlation between the occurrence of Streptococcus mutans (S. mutans) which is considered as the main pathogen responsible for the initiation and development of dental caries with blood groups and Rhesus (Rh) factor that are considered as a genetic predictor of having dental caries among healthy students.

Saliva and blood samples were taken from 40 healthy students whose ages were between 19-23 years old in the College of Dentistry/Al-Iraqia University in Baghdad, Iraq. Estimation of the flow rate and pH was done for all the collected saliva samples within 5 min of saliva collection. Then, 100 µL of saliva was cultured on Mitis salivarius bacitracin agar (MSBA) at 37 °C for 48 h. The colonies of S. mutans were identified by their morphology and biochemical tests. Later, 1 to 2 drops of blood were taken from each student’s thumb to determine the blood group.

This study showed there was a greater prevalence of S. mutans among students of blood group A in contrast to the blood group O. In addition, Rh+ groups were dominant than Rh- groups among the study samples.

S. mutans levels were higher in the blood group A followed by AB, B, O blood groups among the college students studied.