Antibiotic Resistance Studies in Streptococcus mutans Isolated from Dental Plaque Samples

Abstract

Dental plaque is an archetypical biofilm composed of a complex microbial community. It is the etiological agent for major dental diseases such as dental caries and periodontal disease. Streptococcus mutans has been heavily implicated in dental plaque formation. The control of plaque can be achieved by mechanical oral hygiene procedures. However, in many cases, that is not enough to completely get rid of the biofilm. The addition of antiplaque or antimicrobial agents to dental healthcare products has been of value. Antibiotics are found to be simple and effective in achieving this; however, the demerit observed is the increasing resistance of S. mutans to certain commonly prescribed antibiotics, such as ampicillin, amoxicillin, tetracycline, erythromycin, ciprofloxacin, doxycycline and chlorohexidine. The present study assesses the effects of the former five antibiotics on 10 isolates of S. mutans obtained from dental plaque samples. Antibiotic resistance was defined based on lack of zones of inhibition, or on inhibition zone diameters below the required values to be considered susceptible. All 10 isolates were found to be resistant to ampicillin. Seven of the isolates were resistant to amoxicillin and the remaining three were susceptible. Seven of the isolates were resistant to tetracycline; of the remaining three isolates, two of them were susceptible and one was intermediate (neither considered resistant nor susceptible). For erythromycin, five of the isolates were intermediate and the remaining five were resistant. For ciprofloxacin, five of the isolates were intermediate and the remaining five were susceptible. The minimum inhibitory concentration of amoxicillin against the isolates was found to be an average of 0.25 μg/ml, which is the minimum concentration of the antibiotic that was found to be effective against S. mutans.

Keywords: antibiotic resistance, biofilm, dental plaque, plaque control, S. mutans

Cite this Article

Varshini Rana, Albin Joseph, Sneha Saragadam, Dhamodhar P. Antibiotic Resistance Studies in Streptococcus mutans Isolated from Dental Plaque Samples. Research & Reviews: A Journal of Life Sciences. 2019; 9(Issue 1 Special): 64s–72s.