LCx: a diagnostic alternative for the early detection of Mycobacterium tuberculosis complex

Development of an in-house loop-mediated isothermal amplification (LAMP) assay for detection of Mycobacterium tuberculosis and evaluation in sputum samples of Nepalese patients

“…An additional technique, nucleic acid amplification assay (NAA), allows the rapid, sensitive and specific detection of M. tuberculosis in sputum samples by amplifying and detecting specific nucleic acid sequences (CDC, 1992). In addition to the widely used PCR, several other methods of nucleic acid amplification have been used for M. tuberculosis detection (Jonas et al, 1993;Ruiz-Serrano et al, 1998;Iwamoto et al, 2003;Takakura et al, 2005), including loop-mediated isothermal amplification (LAMP), a novel NAA which enables the detection of trace amounts of DNA under isothermal conditions, namely at 64 u C (Notomi et al, 2000). LAMP showing high amplification efficiency has been used for the diagnosis of several diseases (Notomi et al, 2000;Iwamoto et al, 2003;Kuboki et al, 2003;Parida et al, 2004Parida et al, , 2005Kimura et al, 2005;Yoda et al, 2007).…”

Detection of infectious and toxigenic bacteria

“…These have been used to detect C. trachomatis and N. gonorrhoeae 115,116 and M. tuberculosis in a London teaching hospital 117 and in respiratory and nonrespiratory systems. 118 The general consensus is that LCR offers distinct improvements over culture methods especially when pelvic examinations are difficult to perform 116 or when large numbers of patients need to be screened for tuberculosis. However, Shetty and co-workers 117 have pointed out some limitations of the LC 3 test for TB including its expense and its inability to differentiate old and treated TB from re-activated disease.…”

Loop-Mediated Isothermal Amplification (LAMP) for the Direct Detection of Human Pulmonary Infections with Environmental (Nontuberculosis) Mycobacteria

“…The conventional biochemical tests for identification of mycobacterial species are tedious and timeconsuming because of the slow growth of mycobacteria on culture media (9). In addition to the widely used PCR, several other methods of nucleic acid amplification have been used for Mycobacterium tuberculosis detection (10)(11)(12)(13). Loopmediated isothermal amplification (LAMP) is a novel nucleic acid amplification method that enables the detection of trace amounts of DNA under isothermal conditions, namely at 64°C (15).…”

“…The specificity of the LAMP primers was examined by LAMP reaction on DNA mechanically extracted (11) from various mycobacterial strains, including M. tuberculosis, M. bovis Ravenel, M. bovis BCG, M. africanum, M. microti, M. kansasii, M. avium, M. intracellulare, M. shimoidei, M. nonchromogenicum, M. xenopi, M. scrofulaceum, M. gordonae, M. chelonae, and M. fortuitum, found not to have a cross reaction. The sensitivity of LAMP was 100% (32/32) in smear-positive and culture-positive sputum samples and 87.5% (7/8) in smear-negative and culture-positive sputum samples from suspected TB patients.…”