In vitro selection of aptamers against methicillin-resistant Staphylococcus aureus by SELEX

OBJECTIVE To obtain aptamers of methicillin-resistant Staphylococcus aureus(MRSA)by SELEX and observe the binding specificity of aptamer AM6to MRSA so as to lay foundation for developing specific diagnostic reagents and targeted therapies on MRSA.METHODS An 81nt primary random ssDNA library was synthesized in vitro.Aptamers of MRSA were obtained by iterative SELEX procedures,and then their primary structures were analyzed.The specificity of AM6's binding to MRSA was observed by fluorescence microscope and PCR.RESULTS After 20rounds of selection,25ssDNA sequences the same as the expected size were obtained,which had no common conserved sequence.AM6did not bind to methicillin-sensitive Staphylococcus aureus(MSSA),methicillin-resistant coagulase-negative Staphylococcus(MRCNS),or methicillin-sensitive coagulase-negative Staphylococcus(MSCNS),and Escherichia coli,but it bound to MRSA.CONCLUSIONThe aptamers of MRSA can be successfully obtained by SELEX,and AM6can bind to MRSA specifically.