Disclosed are diagnostic methods for determining a subtype of methicillin-resistant Staphylococcus aureus (MRSA) in a biological sample of a mammal. Methods include providing a biological sample of the mammal, performing a PCR analysis of the biological sample, and analyzing the PCR amplicons with respect to their sizes so as to determine for type I, type II, type III, type IV or type V MRSA that may be present in the biological sample. Further example embodiments include using at least one mecA primer pair and/or using at least one Staphylococcus aureus nuc primer pair in the PCR analysis. Further disclosed are methods for screening populations for MRSA, and methods of treating a mammal testing positive for Type IV MRSA. Also disclosed are kits for determining a MRSA subtype in a mammal and isolated primers that may be used in the present methods and kits.