FIG 7 .

phSP6-ProPol can detect M. tuberculosis drug resistance. RIF^r M. tuberculosis and EMB^r M. tuberculosis were either left untreated or treated with rifampin or ethambutol for 16 h. Bacteria were then infected with phSP6-ProPol for 4 h. RNA from each sample was then purified and amplified using RT-PCR. The resultant product was separated by 2% agarose gel electrophoresis and visualized by staining with ethidium bromide. A 1:10 dilution of cDNA derived from the untreated and ethambutol-treated phSP6-ProPol-infected RIF^r strain was made prior to PCR amplification to provide a semiquantitative determination of the reduction of SML synthesis by ethambutol in this strain. The locations of DNA size markers are indicated.