Prevalence of Aggregatibacter actinomycetemcomitans in Saliva from Children aged 7-9 - and evaluation of two different DNA extraction methods

Periodontitis is an inflammatory disease caused by bacterial infection that can lead to loss of supporting tissues around the teeth. Studies show that different ethnic populations demonstrate major differences in prevalence of the disease and in which form the disease occur. The presence of the bacteria Aggregatibacter actinomycetemcomitans (A.a) is associated with the aggressive form of the disease, diagnosed primarily in young people. The present study aims to describe the prevalence of A.a in children aged 7-9 years living in Sweden with different ethnic backgrounds and to evaluate two different ways of extracting bacterial DNA. The hypothesis was that prevalence of A.a would correlate with the origin of the subjects, thus anticipating a higher prevalence in subjects of African origin than those of other ethnicity. Stimulated saliva samples from 85 children were studied. Two methods were used to extract DNA, manually and automatically. qPCR was used to investigate if the samples contained A.a. The essential results showed that the highest prevalence of A.a was found in samples belonging to children with African origin. The manual method extracted DNA in a higher amount and from more samples compared to the automatic method. Sweden is nowadays multicultural and the clinical issues change with the population. Other clinical questions needs to be answered and previous truths need to be reassessed, for example periodontal problems in younger individuals. In this study, the manual method of extracting DNA proved to be more sensitive than the automatic, though more studies need to be conducted to draw any conclusions.