Revisiting susceptibility testing in MDR-TB by a standardized quantitative phenotypic assessment in a European multicentre study

Abstract

The automated DST procedure permits accurate and rapid quantitative resistance profiling of first- and second-line antituberculous drugs. Prospective validation is warranted to determine the impact on patient care.

Individualizing management of extensively drug-resistant tuberculosis: diagnostics, treatment, and biomarkers

“…Nowadays, the MGIT960 is the gold standard. However, treatment of MDR/XDR-TB should be individualized and based on a combination of true minimum inhibitory concentration (MIC) of drugs when testing the MTB isolate in vitro and the plasma levels that can be achieved in the respective patient [17,51,52]. This may become in reach of more laboratories when cheaper MIC methods will be standardized, like the 96-well Sensititre approach [53].…”

“…In high-burden settings, where resources are often limited, molecular resistance assays are used instead as they have a high throughput and superior performance characteristics to conventional culture and drug-susceptibility testing [108]. However, individualized treatment is based on true minimum inhibitory concentration (MIC) of drugs when testing the MTB isolate [17,51,52]. In addition to easy-to-implement MIC testing [109], a central reference laboratory is crucial for optimal treatment outcome in XDR-TB.…”

Classification of drugs to treat multidrug-resistant tuberculosis (MDR-TB): evidence and perspectives

“…High-dose isoniazid should be added to an MDR/XDR-TB regimen when the katG mutation is not documented by the genotype line probe assay (Quest Diagnostics, Madison, NJ, USA) but it should not be counted among the four active drugs (2,10,11). However, very recent evidence suggests this might not be fully true, which might further support adding systematically high dose isoniazid, even in the presence of katG mutation (12).…”

“…Therefore, in quite many cases of isoniazid resistance in the presence of katG mutation, high dose isoniazid is likely to be effective (12).…”

Proposal for a standardised treatment regimen to manage pre- and extensively drug-resistant tuberculosis cases

“…In cases of complete resistance to all the SLIs and to streptomycin, this drug should be removed from the regimen. c. High-dose isoniazid may have a role in cases with low-level resistance [53,54]. It might also be used to treat failures in the shorter MDR-TB regimen, where isoniazid is prescribed at the dose of 10 mg·kg −1 body weight [2].…”