Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum prevalence correlates with salivary microbial burden in Orthodontic patients

Abstract

Objectives: Many factors influence the presence and growth of oral microbial flora, including the use of orthodontic appliances. Although much research has focused on classical oral pathogens, much less information is available to determine the relationship between Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum among these patients. The primary objective of this study was to determine the relationship between oral prevalence of Aggregatibacter and Fusobacterium among orthodontic and non-orthodontic patient saliva samples. Experimental Methods: This study was a retrospective study of previously collected saliva samples from orthodontic (n=55) and non-orthodontic (n=55) patients using an approved protocol. DNA was extracted and screened for Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum. Males and females were equally represented, although a majority of patients participating in this study were Hispanics and ethnic minorities. Results: PCR analysis of the DNA revealed that 54.5% of orthodontic samples harbored significant levels of Aggregatibacter Actinomycetemcomitans, while 29.1% of non-orthodontic samples harbored significant levels of Aggregatibacter actinomycetemcomitans (p=0.0068). In addition, screening for Fusobacterium revealed 38% of orthodontic samples harbored this organism, compared with 33% of non-orthodontic samples (p=0.4599). Screening of these samples using the 16S universal primer revealed AA-positive orthodontic samples had the highest PCR band intensity, with similar band intensity of AA-Negative orthodontic samples AA-positive non-orthodontic samples, AA-negative non-orthodontic samples. While screening for Fusobacterium using the 16S universal primer revealed higher band intensity (microbial burden) among the FN-positive samples among both the orthodontic and non-orthodontic samples. In brief, although microbial burden was lower among the corresponding non-orthodontic samples in general, the FN-positive samples were found to harbor the highest band intensity and microbial burden. Conclusions: This study provides significant data that clearly suggest a correlation between overall microbial oral burden and Aggregatibacter presence in orthodontic patients. Both AA and FN were more prevalent among orthodontic patient samples than non-orthodontic samples, although the difference in the prevalence of FN was not statistically significant. In addition, it was demonstrated the AA was more prevalent than FN overall, and among each of the categories evaluated (orthodontic, non-orthodontic). AA appears to be more prevalent among patients with orthodontic brackets than FN, although both organisms appear to have similar characteristics. This may suggest that although both organisms facilitate heterotypic associations between varying species of oral bacteria, AA may be an earlier or more significant organism in this process in orthodontic patients.