title: Children with severe early childhood caries: streptococci genetic strains within carious and white spot lesions.
abstract: OBJECTIVE
  Mutans streptococci (MS) are one of the major microbiological determinants of dental caries. The objectives of this study are to identify distinct MS and non-MS streptococci strains that are located at carious sites and non-carious enamel surfaces in children with severe early childhood caries (S-ECC), and assess if cariogenic MS and non-cariogenic streptococci might independently exist as primary bacterial strains on distinct sites within the dentition of individual children.
  
  
  METHODS
  Dental plaque from children (N=20; aged 3-6) with S-ECC was collected from carious lesions (CLs), white spot lesions (WSLs) and non-carious enamel surfaces. Streptococcal isolates (N=10-20) from each site were subjected to polymerase chain reaction (PCR) to identify MS, and arbitrarily primed-PCR for assignment of genetic strains. Primary strains were identified as ≥50% of the total isolates surveyed at any site. In several cases, strains were characterized for acidurity using ATP-driven bioluminescence and subjected to PCR-determination of potential MS virulence products. Identification of non-MS was determined by 16S rRNA gene sequencing.
  
  
  RESULTS
  Sixty-four independent MS or non-MS streptococcal strains were identified. All children contained 1-6 strains. In many patients (N=11), single primary MS strains were identified throughout the dentition. In other patients (N=4), primary MS strains were identified within CLs that were distinct from primary strains found on enamel. Streptococcus gordonii strains were identified as primary strains on enamel or WSLs in four children, and in general were less aciduric than MS strains.
  
  
  CONCLUSIONS
  Many children with S-ECC contained only a single primary MS strain that was present in both carious and non-carious sites. In some cases, MS and non-cariogenic S. gordonii strains were found to independently exist as dominant strains at different locations within the dentition of individual children, and the aciduric potential of these strains may influence susceptibility in the development of CLs.
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Gilbert
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Raphael
authors.initials: R
authors.lastname: Joseph
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Vo
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA ; Department of Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Trusha
authors.initials: T
authors.lastname: Patel
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA ; Department of Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Samiya
authors.initials: S
authors.lastname: Chaudhry
authors.affiliation: Department of Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Uyen
authors.initials: U
authors.lastname: Nguyen
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Trevor
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Robinson
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Campbell
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: John
authors.initials: J
authors.lastname: McLennan
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Farielle
authors.initials: F
authors.lastname: Houran
authors.affiliation: Academic DMD Program, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Tristan
authors.initials: T
authors.lastname: Wong
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Kendra
authors.initials: K
authors.lastname: Flann
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Wages
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Palmer
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: John
authors.initials: J
authors.lastname: Peterson
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: John
authors.initials: J
authors.lastname: Engle
authors.affiliation: Department of Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA ; Department of Pathology and Radiology, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Maier
authors.affiliation: Department of Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA ; Department of Pediatric Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Curtis A
authors.initials: CA
authors.lastname: Machida
keywords: Streptococcus gordonii; Streptococcus mutans; distribution of genotypic mutans; oral streptococci; severe early childhood caries; streptococcal strains