Isoniazid and rifampicin resistance are assayed phenotypically by the resistance ratio, absolute concentration or proportion methods. Assay methods are often difficult to standardise and the World Health Organization (WHO) Global Programme on Drug Resistance is attempting to produce standardised drug resistance data worldwide. Broth-based methods are faster than solid media systems, and a commercial radiometric system, the Bactec 460, is arguably the fastest method and permits testing to be completed within 7–14 days; however, this method is expensive and requires disposal of radioactive material. Novel phenotypic methods that utilise mycobacteriophages have shown promise. Other molecular detection systems require knowledge of the genes encoding the drug target (the and genes for isoniazid; for rifampicin) and the mutations producing resistance. These genotypic methods are limited in that not all resistance mechanisms are known, but advanced assays for rifampicin resistance that use gene sequencing, heteroduplex analysis, solid-phase hybridisation or single-strand conformation polymorphism analysis are becoming available.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error