Diagnosing Drug-Resistant Tuberculosis with the Xpert<sup>®</sup>MTB/RIF. The Risk for Rifampin Susceptible Cases

Abstract

Setting: Tuberculosis clinic in México. Objective: Since the Xpert®MTB/RIF does not detect resistance to isoniazid, our objective was to emphasize the need for additional drug susceptibility testing. Design: A prospective study. All patients with an Xpert®MTB/RIF and a positive tuberculosis culture with drug susceptibility testing were included. Results: 70 patients were included. Forty-two (60%) had a history of previous treatment for TB. Fourteen patients (20%) had a strain resistant to isoniazid (H), twelve of them (85.7%) with a history of TB treatment in the past vs. 2 (7.1%) among new cases (p = 0.028). Four patients (5.7%) had resistance to rifampin (R); three of them were previously treated cases. Additionally, six patients with a negative Xpert test (8.6%) had a positive MGIT culture; three of them were resistant to H (the 3 were poly-resistant). Two patients with a positive Xpert®MTB/RIF test without R resistance were phenotypically multidrug-resistant. Conclusion: Isoniazid resistance is associated with overall increased treatment failure, relapse, and acquired multidrug resistance in patients treated with regimens containing only first-line tuberculosis drugs. It is urgent that national TB programs implement the necessary infrastructure to complement the Xpert®MTB/RIF results with DST either by phenotypic or genotypic methods.

Multi drugs resistance to Diabetes Mellitus patients with tuberculosis in Manado City

“…Very importantly, in the same policy statement which emphasizes that DST for anti-TB medicines other than rifampicin should also be offered. 3 Thus, along with TB diagnosis, drug susceptibility testing (DST) has become an urgent clinical requirement for a timely constitution of proper and effective TB treatment. However, TB diagnostic and laboratory capacity are still deficient in many areas of highly TB-burdened countries.…”