In 1975, it was reported that MTB metabolic end-products could be detected by using a 14C-labeled substrate (Parsons et al., 2004). This system has been widely performed in clinical laboratories in the past two decades and is considered the gold standard in many ways (Tortoli et al., 2002). Radioactive BACTEC 460TB system (Becton Dickinson) has been developed based on detection of 14CO2 produced by consumption of a 14C-labeled substrate. This system is used to test the metabolism of the organism in the presence of all first-line drugs (SM, INH, RIF, EMB, PZA) (Tortoli et al., 2000). This system is reliable and rapid for detection of susceptibility of MTB to these drugs (Scarparo et al., 2004). Results of susceptibility test can be available in 1 week compared with 3-4 weeks when solid media is used (Parsons et al., 2004). BACTEC 460TB is the proposed reference method for PZA susceptibility testing by NCCLS (Scarparo et al., 2004), but this system uses radioactive substrates (Johansen et al., 2004).
Was this article helpful?