title: Serotype specific polymerase chain reaction identifies a higher prevalence of streptococcus mutans serotype k and e in a random group of children with dental caries from the Southern region of India.
abstract: BACKGROUND
  The development of dental caries has been associated with the oral prevalence of Streptococcus mutans. Four serotypes of S. mutans have been reported, namely serotype c, e, f, and k that are classified based on the composition and linkages of cell wall polysaccharides, response to physiological reactions, sero-specificity and 16s rRNA homology. Although the oral prevalence of S. mutans serotype c in Indian subjects with or without caries is known, the prevalence of the other three serotypes, e, f, and k are not known. Hence in this study, we have investigated the occurrence of the e, f, and k serotypes in children with or without caries within the age group of 6-12 years.
  
  
  METHODS
  Genomic DNA isolated from whole saliva of caries active (CA) and caries free (CF) groups were first screened for the presence of S. mutans by strain specific polymerase chain reaction (PCR). Those samples that tested positive for the presence of S. mutans were further analyzed by serotype specific PCR to identify the prevalence of the serotypes.
  
  
  RESULTS
  Strain specific PCR indicated a higher prevalence of S. mutans in CA group (80%) relative to CF group (43%). Further analysis of the S. mutans positive samples in both groups indicated a higher prevalence of serotype k and e, followed by serotype f in CA group.
  
  
  CONCLUSIONS
  The present data clearly establishes a novel S. mutans serotype prevalence hierarchy in children from this region, compared with those that have been reported elsewhere. Besides, the data are also clinically significant as the occurrence of serotype k has been associated with infective endocarditis.
authors.affiliation: Department of Pediatric Dentistry, Rajah Muthiah Dental College and Hospital, Annamalai University, Annamalai Nagar, Chidambaram, Tamil Nadu, India.
authors.forename: Arun Prasad
authors.initials: AP
authors.lastname: Rao
authors.affiliation: Department of Oral Medicine and Radiology, Rajah Muthiah Dental College and Hospital, Annamalai University, Annamalai Nagar, Chidambaram, Tamil Nadu, India.
authors.forename: Ravi David
authors.initials: RD
authors.lastname: Austin
keywords: Streptococcus mutans serotype specific polymerase chain reaction; Streptococcus mutans serotypes e; Streptococcus mutans serotypes in India; Streptococcus mutans serotypes in dental caries; f and k in dental caries