Streptococcus mutans and Streptococcus sobrinus distribution in the saliva and plaque of Iranian population: Higher prevalence of S. mutans serotypes f and k

Int J Dent Hyg. 2021 May;19(2):193-200. doi: 10.1111/idh.12485. Epub 2021 Jan 6.


Objective: This study aimed to find the relation of the MS co-existence with the decayed, missing (Extracted) and filled teeth (DMFT) score and the prevalence of Streptococcus mutans serotypes in the Iranian population.

Methods: In this cross-sectional research conducted in 2018, volunteers aged 10-60< years were measured by population selection criteria. PCR technique was used to screen MS serotypes in the homogenized saliva and plaque samples.

Results: 499 subjects met the selection criteria of the study population. Out of 499 samples, 448 samples were finalized for serotype determination and DMFT relation evaluation. From 448, 348 (77.6%) samples harboured only S. mutans, 44 (9.8%) had both S. mutans and S. sobrinus, 6 (1.3%) were positive for S. sobrinus alone, and 94 (20.9%) were free of both specious. The mean DMFT score in people with S. mutans (6.7) was higher than S. mutans negative (4.6) participants (p < 0.05). In people with both S. mutans and S. sobrinus, the mean DMFT did not change significantly. The frequency of c, e, f and k serotypes was 47.7, 22.7, 27.5 and 22.1%, respectively. The mean DMFT score in participants with serotype e was significantly higher than others (p < .05).

Conclusions: People can acquire different S. mutans serotypes over a lifetime. The high prevalence rate of serotype k, a systemic S. mutans serotype, calls worldwide studies on the prevalence of serotype k strains.

Keywords: Streptococcus mutans; Streptococcus sobrinus; DMFT; Iran; serotype.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Cross-Sectional Studies
  • Dental Caries* / epidemiology
  • Humans
  • Iran / epidemiology
  • Middle Aged
  • Prevalence
  • Saliva
  • Serogroup
  • Streptococcus mutans
  • Streptococcus sobrinus*
  • Young Adult