Oral Micro-Flora Estimation in Caries Active and Caries Inactive Indian Children using Culture Techniques and PCR Analysis: A Preliminary Study

Background: Although Streptococcus mutans has been implicated as major etiologic agent in development of Early Childhood Caries (ECC), but its not present in all children with caries and it remains to be elucidated whether a single or specific consortium of bacteria is responsible for caries.

Aim: To evaluate oral micro flora of Indian children suffering from ECC and its comparison in children with no caries using cultivation combined with molecular techniques.

Methods: Dental plaque samples from caries inactive surfaces and carious dentin from deep lesions in caries active (n=56) 2- 6 years children were collected using sterile excavator in storage vials. For comparison, plaque samples were collected from 32 caries free children during same time. The samples were subjected to various aerobic and anaerobic culture techniques. Cultivable colonies were identified using automated microbial identification techniques using Matrix Assisted Laser desorption and Ionization (MALDI) and 16s r DNA sequencing for Lactobacillus. Identified microbial species from each sample were compiled to estimate the micro-flora of the children.

Results: Main organisms isolated were: Streptococcal species mainly S anginosus, S salivarus, S gordonii: Lactobacilli spp; Coagulase negative Staphylococci, Staph epidermidis, Staph aureus. Other organisms such as Kleibsella spp, Acinetobacter, Enterococcus, E coli could also be found. However, no significant difference in the frequency of identification of these organisms was found in two groups except Lactobacilli species (p= 0.008) which was further confirmed by 16s r DNA sequencing for Lactobacillus species.

Conclusion: Caries activity was found to be associated with presence of diverse microflora but Lactobacilli species was found to be significantly more in caries active children which was confirmed by molecular techniques.