Cloned Gene Confers Low Level Erythromycin but High Level Clindamycin Resistance in NZ131.

The most common macrolide resistance mechanisms in streptococci are the presence of methylase encoding genes and or the presence of efflux encoded by genes. In the present study we aimed to show the effects of the gene under isogenic conditions on the activities of macrolides and lincosamides in streptococci. Total DNA was extracted from C1, and the gene was amplified with or without the regulatory region using modified primer with insertion of restriction sites to clone in to pUC18. Transformants were selected after electroporation of DB10. The recombinant plasmids were purified and merged to pJIM2246 to transform Gram positive bacteria. Recombinant pJIM2246 plasmids with the gene were then introduced into NZ131 by electroporation. After transformation with without regulatory region the minimal inhibitory concentration (MIC) for erythromycin and clindamycin increased from ≤0.06 to ≤0.06 to 8 and >128 mg/L, respectively. Induction with erythromycin affected the MICs for clindamycin of transformed with with the regulatory region. Double disk testing showed that induction with erythromycin and azithromycin for the transformed with , and regulatory regions decreased the clindamycin inhibition zone but not telithromycin. The gene in isogenic conditions confers low level resistance to erythromycin and high level resistance to clindamycin. The different induction and resistance profiles of compared to other genes suggest that the methylation of ErmTR may be different than well studied methylases.