Determination of the Minimum Inhibition Concentrations for cell wall Inhibitors ß -lactame (Amoxycellin and Cloxacillin) against pathogenic Staphylocoocusaureus

Abstract

The objective of this study was to determine the MICs of ß -lactame Amoxicillin and Cloxacillin for 30 Isolates of pathogenic Staphylocoocus aureus by manual Etest in comparison with disk diffusion test. Staphylocoocus aureus strains and control strains were provided by Khartoum hospitals, central lab (soba), the Central Public Health Laboratory and National Center of Medicinal and Aromatic plants. The Isolates were obtained from wounds, skin, blood and urine samples, The samples were tested for ß -lactame susceptibility by manual E-test and disk diffusion test. Most strains of Staphylococcus aureus (about 76.7%) showed sensitivity to ß -lactame Cloxacillin with an MIC range between 1.25 and 0.06µ g/ml, Seventy percent of the tested strains showed a high resistance to Amoxicillins. The present study did not demonstrate any significant difference in resistance to the two antibiotics using disk diffusion method and manual E-test method. In Conclusion the MIC values of clinical isolates can be estimated using manual E-test method, since it is more reproducible, reliable, easy and cheaper when compared with the commercial E-test strip. The agar disc diffusion method was found reliable, rapid, easy and inexpensive but demonstrate only diffusion. The use of E-test in research and hospitals in Sudan is recommended, because E-test is a quantitative technique for determining the antimicrobial susceptibility of Gram negative and Gram positive aerobic bacteria easily