Colonization of mutans streptococci in Costa Rican children from a high-risk population

Sylvia Gudiño, Norman Rojas, Cristina Castro, Marianela Rodríguez, Maritza Vega, Lydia M. López

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Purpose: The aim of the study was to determine the colonization of mutans streptococci (MS) in dental biofilm and saliva of children from a high-risk population with low socioeconomic status from San José, Costa Rica. Methods: A total of 68 healthy babies from 8 to 20 months of age (mean age=13 months), with caries-free status and cariogenic feeding habits (eg, nursing bottle- or breast-feeding on demand) were examined. Children divided in two groups (<13 months and 14-20 months). Samples from dental biofilm and saliva from each subject were processed and plated in blood agar (BA) and Mitis-Salivarius-Bacitracin agar (MSB) to determine MS percentage. Statistical analysis included the analysis of variance test, and stratification by age of MS levels. Results: Detectable MS levels in dental biofilm and saliva were found in 75% and 72% of children, respectively. Counts higher than 20000 colony forming units (CFU) per ml were found in 4% of saliva and in 35% of biofilm samples. The two groups showed significant differences in MS levels for dental biofilm (P=.036) and saliva (P=.009). Children older than 17 months presented higher MS levels (P<.05). Analysis by MS levels (<0.1%; 0.1-1.0%; >1.0% of MS) The two groups showed an insignificant association with increasing mean age. MS density was associated with mean number of erupted primary molars. Conclusions: Mutans streptococci colonization of dental biofilm and saliva from high caries risk infants is associated with age and dental development.

Original languageEnglish (US)
Pages (from-to)36-40
Number of pages5
JournalJournal of Dentistry for Children
Issue number1
StatePublished - Jan 1 2007


  • Colonization
  • Dental biofilm
  • Dental caries
  • Mutans streptococci
  • Saliva

ASJC Scopus subject areas

  • Dentistry(all)
  • Medicine(all)


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