ACER3 and tuberculosis: To date, nine genes are known to be linked to resistance to first-line anti-TB drugs; katG, inhA, aphC, and kasA for INH resistance, rpoB for RIF resistance, rpsL and rrs for strptomycin (STR) resistance, embB for ethambtol (EMB) resistance, and pncA for pyazinamid (PZA) resistance.