Evaluation of Antibacterial Activity of Two Different Honeys against Clinical Isolates of β-hemolytic Streptococci Group A

Abstract

Introduction: The aim of this investigation was to evaluate in vitro antibacterial activity of horse chestnut honey and acacia honey at different concentrations against clinical isolates of the β-hemolytic streptococci group A (BHS-A). Honey’s active compounds have multiple therapeutic
effects and it is used as traditional medicine for treatment and prevention of various illnesses.
Materials and methods: The antimicrobial effects of two honeys were tested on forty-four strains of BHS-A, isolated from the throat by a modified disk diffusion method. A bacterial suspension of BHSA strains was plated onto Müller-Hinton agar with 5% defibrinated horse blood. Using a sterile 8 mm diameter cork borer, wells were cut in the agar and into each was introduced 100µL of the different concentrations of the honey solution (25 %v/v, 50 %v/v, 75% v/v and 100%v/v). A disk of penicillin was added as the positive control. The plates were incubated aerobically for18-24 hours at 36 (± 1)°C and zones of inhibition were measured.
Results: The average diameter of the inhibition zones of acacia honey (100 %v/v) was 12.48 mm ± 1.73 mm, for acacia honey (75 %v/v) it was 11.06 mm±1.24 mm and for horse chestnut honey (100 %v/v) it was 11.08 mm ± 1.02 mm. The positive control showed the average diameter of 30.45 mm ± 3.21 mm. Statistical significance (p < 0.05) was observed comparing the zone diameters of the acacia honey (100%) and antibiotic penicillin, and between the horse chestnut honey (100%) and antibiotic penicillin.
Conclusion: Acacia and horse chestnut honeys exhibit limited but effective antibacterial activity upon clinical isolates of BHS-A.