**1.4 Mycobacteriophage-based method**

fragment length polymorphism insertion analysis of genomic DNA which demonstrated that MDR-TB cases (74.0%) were more likely to be identified in clusters than anti-TB drug suscep‐ tible cases (33.6%) [27]. Xpert MTB/RIF assay recently has been introduced which meets the requirements of effective diagnosis of pulmonary TB as the following : allowing detection of both the *Mycobacterium tuberculosis* complex and resistance to the principal anti-TB drugs, especially rifampicin (RIF or R), availability on a global scale with standardized-easy use and robust diagnostic tools recently has been introduced [28]. This assay is a nucleic acid amplifi‐ cation test for detection of rifampicin resistance-associated mutations of the *rpoB* gene and *Mycobacterium tuberculosis* complex DNA in sputum [28]. It can be designed for use with other systems to automate and integrate sample processing, nucleic acid amplification, and detection of target sequences using reverse transcriptase polymerase chain reaction (PCR) and real-time PCR [28]. Between 2007-2009, the WHO has approved several drug-resistant TB diagnostic tests such as liquid culture (MGIT®, an automated liquid culture, developed by BD Diagnostic Systems, 2007) which has been used at the 10th Zonal Tuberculosis and Chest Disease Centre, Chiang Mai, Thailand, line-probe assays (INNO-Lipa®, line-probe assay that requires culture, developed by Innogenetics, 2008), noncommercial culture and drug susceptibility testing (Microscopic Observation Drug Susceptibility (MODS), developed by Academic Laboratories, 2009; Nitrate reductase assay, developed by Academic Laboratories, 2009; and Colorimetric drug susceptibility testing, developed by Academic Laboratories, 2009) [29]. GeneXpert MTB/ RIF®, a new automated nucleic acid amplification technique which was developed by Cepheid, The Foundation for Innovative New Diagnostics (FIND) and University of Medicine and Dentistry of New Jersey (UMDNJ) was reviewed by the WHO in 2011 [29] and currently has been recommended to measure the *Mycobacterium tuberculosis* DNA and the rifampicinresistance sequence worldwide. This new technique has been set in Thailand at least 6 sets including the one set at the 10th Zonal Tuberculosis and Chest Disease Centre, Chiang Mai, Thailand in collaboration with the Unites States Centres for Disease Control and Prevention (US-CDC) for reference laboratories in Thailand. GeneXpert test's sensitivity is moderate at 67.2% in AFB-smear negative cases at one-time smear staining of the specimens, and increases to 80% when is performed three times [28]. This test provides the results within two hours and requires minimal training of the laboratory workers [29]. The limitations of the test are requirement of a consistent source of electricity that will limit its use outside of the settings where a regular electric power supply can be guaranteed, its expensive cost of the instrument, and cost per test cartridge [29]. Mishra B *et al*. used the automated BACTEC 460 TB system in study the emergence of drug-resistant TB at an urban tertiary care hospital in South India which revealed that 37.2% were MDR-TB isolates whereas 42% of the pulmonary *Mycobacte‐ rium tuberculosis* isolates and 20.4% of extra-pulmonary isolates were MDR [30]. Phenotypic and genotypic detections of anti-TB drug resistance are described as the following [31- 49]:

244 Tuberculosis - Current Issues in Diagnosis and Management

This method has less equiptment, suitable for decentralization, 93% rifampicin susceptibility

**1. Phenotypic detection**

at 88% predictive value of resistance.

**1.2 Mycobacteria Growth Indicator Tube (MGIT) Systems**

**1.1 Slide DST**

### **1.4.1 Commercial FASTPlaque assay (FASTPlaque TB test and FastPlaque TB-**
