<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>

Nitrogen is one of the important constituents of the plants. It is fixed in legume plants from the atmosphere by the association of beneficial gram negative soil bacteria named rhizobia. This study aimed to distinguish the morpho-physiological characteristics of naturally growing rhizobia having higher environmental and external stress tolerance. Twenty-two isolates were isolated from country bean root nodules and characterized based on different tests. The isolates varied from one another with level of parameters of the treatments. Most of them exhibited cream color colonies and some isolates evolved white and pink colonies. The average colony size of the isolates was ranged between 0.83 to 2.83 mm after one day and 1.33 to 5.00 mm after two days. Among them, 17 isolates were alkali producers, three isolates were acid producer and only two isolates produced neutral mucous. All the isolates showed complete resistance at pH 5.0 to 10.0, 2% NaCl, 10 to 42oC temperature, and 0.1 mM of heavy metallic salt MnCl2, FeCl3 and PbCl3. Nevertheless, most of the isolates also tolerated pH 4.0; 3 to 7% NaCl; 47oC temperature; 0.1 mM CuSO4. On the other hand, a few numbers of the isolates resisted 100 µg/ml and 200 µg/ml ampicillin, kanamycin and tetracycline antibiotics. Therefore, exploration of country bean rhizobia for their environmental stress tolerance capacity might be a core study for the production of cost-effective bio-fertilizer to boost up country bean yield.