Comparison of Antimicrobial Potency Assay of Common Antibiotic Prophylaxis Drugs Recommended in Dentistry for Preventing Infective Endocarditis - An Invitro Study from Chennai, India

Abstract

BACKGROUND Infective endocarditis [IE] prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. The study intended to compare the antimicrobial potency of amoxicillin, cephalexin, and clindamycin against Streptococcus mutans, the common causative organism of dental infections. The objective was to assess the potency of recommended choice of antibiotics and its efficacy among each other in infective endocarditis prophylaxis during dental procedures. METHODS Saliva samples [N = 20] were collected from patients susceptible for IE and Streptococcus mutans was cultured in Infusion Agar. The principle used in this study was based on the Kirby - Bauer disc diffusion Antimicrobial Susceptibility Test [AST] Method and minimum inhibitory concentration [MIC]. In this method, the three HiMedia antibiotic discs of amoxicillin, cephalexin and clindamycin were loaded and assessed for measurable “zone of inhibition” against mutans. RESULTS One-way ANOVA was used to compare the means of zone of inhibition of each disc. The test was statistically significant with F value of 4.093 at P value 0.038. Post hoc analysis was conducted using Tukey’s HSD test as one-way ANOVA was statistically significant. The mean difference of 13.16 mm between amoxicillin and cephalexin was found to be statistically significant at P value 0.041 with lower and upper bound at 0.527 and 25.806 respectively. The mean difference of 2.65 mm between amoxicillin and clindamycin and - 10.50 mm between cephalexin and clindamycin was not found to be statistically significant. CONCLUSIONS Amoxicillin showed to be more potent among the antibiotics chosen for this study. Clindamycin showed to be a better alternative to cephalexin and could be the first choice in case of patients allergic to penicillin group of drugs. KEY WORDS Antibiotic Prophylaxis, Infective Endocarditis, Antimicrobial Potency, Minimum Inhibitory Concentration [MIC], Antimicrobial Susceptibility Test [AST], Kirby Bauer Disk Diffusion Method