If a 62-year-old patient shows MTB detected with rifampicin resistant not detected, what is the next step?

In the case of a 62-year-old patient with a confirmed presence of Mycobacterium tuberculosis (MTB) that is detected but shows no resistance to rifampicin, the most appropriate next step is to classify the case as drug-susceptible TB and initiate first-line treatment.

Rifampicin is a key drug in the first-line treatment regimen for tuberculosis, and its absence of resistance indicates that the standard treatment can be safely and effectively administered to the patient. First-line treatment typically includes a combination of isoniazid, rifampicin, pyrazinamide, and ethambutol, which is effective against drug-susceptible TB.

The other options do not align with the test results. Recollecting sputum for a repeat Xpert test or conducting a chest X-ray would not be necessary at this stage since the current laboratory test has already confirmed the presence of MTB without rifampicin resistance. Classifying the condition as drug-resistant TB and starting second-line drugs is also incorrect because the absence of rifampicin resistance categorically points towards susceptibility. Therefore, it is crucial to start the appropriate first-line treatment based on the susceptibility findings.