Antibacterial efficacy of black seed honey in combination with penicillin and amoxiclav against gram-positive bacteria

Abstract

<p class="abstract"><strong>Background:</strong> The emergence of antimicrobial resistance possesses a great threat for the existence of mankind. Antibiotics like penicillin and amoxiclav are at the brink of losing their efficacy entirely in exposure to resistant bacteria. Thus, the present study was aimed to find out the antibacterial efficacy of black seed honey as an alternative natural source which can act independently and boost the efficacy of standard drugs alongside.</p><p class="abstract"><strong>Methods:</strong> Penicillin, amoxiclav and black seed honey were first individually trailed against four gram-positive bacteria - <em>Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis </em>and<em> Micrococcus luteus</em>.<strong> </strong>Afterwards, penicillin and amoxiclav were used in combination with honey and compared the synergistic effects with their individual efficacy. Zones of inhibition from well diffusion method, percentage inhibition, minimum inhibitory and bactericidal concentrations by microdilution method were determined in the present study. </p><p class="abstract"><strong>Results:</strong> Black seed honey alone demonstrated great inhibitory potential against <em>S. aureus </em>(9.7 mm), <em>S. epidermidis </em>(9.9 mm) and <em>M. luteus</em> (9.3 mm) in well diffusion method. Moreover, its combination with amoxiclav showed synergistic effect against all bacteria except <em>S. epidermidis</em>. However, its conjugation with penicillin was not able to produce any synergism as exhibited by zones of inhibition. The lowest concentration (1.56%) of honey applied individually or in combination in microdilution method found<strong> </strong>highly effective which established an inverse dose dependent relationship with efficacy.</p><p class="abstract"><strong>Conclusions:</strong> From the data it can be concluded that the black seed honey is a highly potent natural agent which can be utilized in antimicrobial therapy. However, further investigation is recommended to identify the responsible compound for such activity.</p>