Estimation of Erythromycin and inducible Clindamycin Resistance in Saphylococcus aureus Isolated from Clinical Cases

To detect Inducible Clindamycin Resistance ICR according to12, flattening of the Clindamycin zone adjacent to the Erythromycin disk (referred to as the D-Zone)10 was indication of the positive results.The molecular detection of ErmA gene was performed by using Polymerase Chain Reaction (PCR) technique, the primer used to amplified the target (ErmA) gene as described by 13 was shown in table (1). PCR amplification was performed for detection of Erythromycin and Clindamycin resistance gene (ErmA gene), as described by13, included an initial denaturation of DNA at 94 C° for 5 minutes; followed by 35 cycles each of Denaturation at 94 C° for 30 seconds; Annealing at 55 C° for 30 sec and Extension at 72C° for 30sec,followed by a Final extension at 72C° for 4 minutes and Hold at 4 C. To visualized the amplicon (190 bp), 1.4 %Agarose was used which stained with 5pl (0.5pg/ml) of Ethidium Bromide, electrophoresis was performed at 65 Volts for 1 hour and finally visualized by using gel documentation14. [...]Erythromycin diffuses outward into Zone, bacterial resistance to Clindamycin is induced prior to its diffusion from the neighboring disk15. [...]higher than27 who found the rate of D-test positive was in (2.2%). [...]there was no indication to other type of Clindamycin resistance phenotypes such as fogy or hazy D-phenotype with small colonies growing towards the Clindamycin disc inside the D zone or HD phenotype with two zones of growth around (sub population inside the Clindamycin sensitive zone Clindamycin disc).