TetM and TetS are ribosomal protection proteins that prevent tetracycline from binding effectively to bacterial ribosomes, conferring resistance to tetracycline, doxycycline, and minocycline. They are common in gram-positive bacteria including streptococci and staphylococci.
Detection of tetM or tetS in molecular susceptibility testing helps predict tetracycline resistance and guide antibiotic selection. Sample type is typically a culture isolate or direct clinical specimen.