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Antibiotic Sensitivity and Antibacterial Activity of Micrococcus spp. SCS1

Subed Chandra Dev Sharma, Mohammad Shariar Shovon, Sarowar Jahan MG, Asaduzzaman AKM, Bulbuli Khatun, Tanzima Yeasmin and Narayan Roy

The xylanase producing bacterial strains were isolated from bamboo garden waste. The strains were isolated on xylan agar media and screening was carried out by xylanolysis method. To test the sensitivity of the isolates, seven different antibiotics were used. The strains showed sensitivity to Ampicillin,Amoxycillin, Bacitracin, Chloramphenical, Doxycyclin, Erythromycin and Kanamycin when they were tested by disc diffusion method on nutrient agar plate and confirmed by antibiotic spread plate method. Ethyl acetate was used for solvent extraction of antimicrobial principals from the culture filtrate. The ethyl acetate extract ofMicrococcus sp SCS1 showed promising antibacterial activity against a number of gram positive (Bacillus subtilis and Staphylococcus aureus) and gram negative (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella shiga, Salmonella typhi and Klebsiella Pneumonia) pathogenic bacteria. The zone of inhibition against pathogenic bacteria ranged from 08 – 22 mm. The minimum inhibitory concentration (MIC) of the extract against Escherichia coli, Salmonella typhi, Salmonella dysenteriae, Shigella dysenteriae, Shigella shiga, Bacillus subtilis and Staphylococcus aureuswere 128,256, 256, 64, 128, 256 and 256g/ml respectively. The extract exhibited cytotoxic effects in brine shrimp lethality bioassay with LC50 value of 30 g/ml.