Antimicrobial Efficacy of Lipopeptide Antibiotic, Lantibiotic and Cationic Bisbiguanide against Enterococcus faecalis Biofilm: An In-vitro Study

Abstract

Introduction: Cyclic lipopeptides, lantibiotics are newer antimicrobials showing promising efficacy against various grampositive micro-organisms. Daptomycin is a cyclic lipopeptide antibiotic with potent bactericidal activity against most grampositive organisms. Nisin is a naturally occurring antimicrobial peptide produced by strains of Lactococcus lactis. Aim: To compare the antimicrobial efficacy of cyclic lipopeptide antibiotics with beta-lactamase inhibitors (Daptomycin-Ceftaroline) at 40 µg and 80 µg, lantibiotics (Nisin) at 25 mg and 50 mg, bisbiguanide (2% Chlorhexidine) and 3% Sodium hypochlorite against E. faecalis biofilm when used as irrigating solutions. Materials and Methods: Forty-five primary teeth were decoronated, sectioned along the midsagittal plane and each half was used as a sample. E. faecalis, biofilm which was grown on the tooth surface for three weeks, was removed by vortexing and an emulsion was prepared by adding 1.5 mL of saline. The samples were distributed into six groups (n=15, each group), Group I: D1-Daptomycin mixed with ceftaroline at 80 µg, Group II: D2-Daptomycin mixed with ceftaroline at 40 µg, Group III: N1-Nisin at 25 mg, Group IV: N2-Nisin at 50 mg, Group V: CHX- 2% Chlorhexidine, Group VI: NaOCl -3% Sodium hypochlorite. The disks of medicaments were prepared and placed in the petri dishes and zone of inhibition was assessed. Data obtained were analysed by One-way Analysis of Variance test and Post-Hoc multiple comparisons test and paired t-test. Results: Intragroup comparison showed no statistical significance when the mean zone of inhibition was observed after two days and seven days in all the groups except for NaOCl group (p-value=0.023.) When intergroup comparison was done, D2 showed highest inhibition of bacteria followed by D1>N2>CHX>N1>NaOCl at 2nd day. At 7th day D2 had highest zone of inhibition followed by CHX>D1>N2>N1>NaOCl. Conclusion: Daptomycin mixed with ceftaroline at 80 µg showed better antibacterial effect than all the tested groups but the cost and availability make them difficult to use as an intracanal irrigant.

Keywords

• chlorhexidine
• canal disinfection
• daptomycin
• nisin
• primary teeth