Diagnostic Opportunities for Optimizing Management of Multidrug-Resistant Tuberculosis (MDR-TB) in Tanzania

BACKGROUND: Tanzania is one of the countries confronting a multidrug-resistant tuberculosis (MDR-TB) epidemic. RESEARCH: Research studies on drug susceptibility testing (DST) for second-line TB drugs given to Tanzanian MDR-TB patients has demonstrated mycobacterial resistance to important MDR-TB drugs, such as ethionamide, ofloxacin, amikacin, kanamycin, and pyrazinamide. Likewise, pharmacokinetic studies have shown a high frequency of patients with circulating serum drug levels below the expected ranges, especially for levofloxacin and kanamycin – key drugs in MDR-TB treatment that also affect ex-vivo plasma drug activity. RECOMMENDATIONS: We suggest using molecular diagnostic assays, such as the GenoType MTBDRplus test, and inhA and/or katG genotypic results to optimize MDR-TB treatment. Quantitative drug susceptibility can guide the selection of options for second-line anti-TB drugs. The TB drug assay, an alternative biomarker for therapeutic drug monitoring, can identify patients who have extensively drug-resistant TB or are exposed to suboptimal serum drug levels of, specifically, levofloxacin and kanamycin.