Antibacterial Activity of Green Tea Extract against Staphylococcus aureus Nasal Carriage Among Health Care Workers in Omdurman Teaching Hospital

Abstract

This is a descriptive cross sectional study conducted during the period from February to March 2015 to determine the antibacterial activity of green tea extract against Staphylococcus aureus nasal carriage among health care workers in Omdurman Teaching Hospital. A total of 100 nasal swabs were collected from healthcare workers in Omdurman Teaching Hospital. These specimens were inoculated onto Manitol salt agar media and incubated aerobically at 37°C for 24 hours. The isolates were then identified using the conventional method. Nineteen out of 100 patients were found to harbour S. aureus (19%), of them, 8 were isolated from males and 11from females. Age of participants range between 25-45 years. The antibiotic susceptibility testing was performed using standard disk diffusion method. The results showed that all S. aureus isolates were resistant to penicillin. Out of the 19 S. aureus isolates, 15(79%) were susceptible to cefoxitin while the reminded 4(21%) were cefoxitin resistant. Cefoxitin resistant isolates termed to be methicillin resistant Staphylococcus aureus (MRSA). The antibacterial activity of green tea against Staphylococcus aureus nasal carriage, MRSA and S. auerus ATCC 25923, was performed at different concentrations in water and methanol extracts using the agar dilution method. Both water and methanol extracts of green tea showed antibacterial activity against all the isolates of S. aureus, MRSA and S. auerus ATCC 25923, (P=0.001). The MIC of green tea extracts from water and methanol was obtained by agar diffusion method, they were 25 mg/ml and 12.5 mg/ml respectively for S. aureus isolates. Gas chromatography analysis revealed that 23 chemical compounds of green tea and the compounds were identified qualitatively by the Retention time and quantitatively by the area under the curve.