Effect of a Chronic Nail-Biting Habit on the Oral Carriage of Enterobacteriaceae

Oral Microbiol Immunol. 2007 Feb;22(1):1-4. doi: 10.1111/j.1399-302X.2007.00291.x.


Background/aims: Nail biting is a common oral habit in children and young adults. However, its effect on the oral carriage of Enterobacteriaceae is unclear. The purpose of the study was to evaluate the differences in prevalence of Enterobacteriaceae in saliva samples from subjects with and without a nail-biting habit.

Methods: Saliva samples were taken from 25 subjects who were nail-biters and 34 subjects with no oral habit. The mean chronological age for all subjects was 13.5 +/- 1.9 years. The saliva samples were studied microbiologically. A Pearson chi-squared test was performed to compare the prevalence of Enterobacteriaceae in the saliva samples of the subjects with and without nail-biting habits.

Results: Statistically significant differences were found in the prevalence of Escherichia coli and total Enterobacteriaceae between both groups (P < 0.001). E. coli, Enterobacter aerogenes, Enterobacter cloacae and Enterobacter gergoviae were found in the saliva samples of 19 of the 25 nail-biting subjects (76%), whereas E. coli, E. aerogenes and E. cloacae were detected in the saliva samples of only nine of the 34 subjects who were not nail-biters (26.5%).

Conclusion: According to the results of the present study, the Enterobacteriaceae were more prevalent in the oral cavities of children with nail-biting habits than in children with no oral habit.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Child
  • Dental Plaque Index
  • Enterobacter / classification
  • Enterobacter / isolation & purification
  • Enterobacter aerogenes / isolation & purification
  • Enterobacter cloacae / isolation & purification
  • Enterobacteriaceae / isolation & purification*
  • Escherichia coli / isolation & purification
  • Female
  • Humans
  • Male
  • Mouth / microbiology*
  • Nail Biting* / adverse effects
  • Oral Hygiene
  • Saliva / microbiology