Evaluation of a rapid bacteriophage-based method for the detection of Mycobacterium tuberculosis in clinical samples

Abstract

Rapid, sensitive and low-cost methods are needed urgently for the detection of Mycobacterium tuberculosis in clinical samples, especially in developing countries. To this end, the clinical performance of FASTPlaqueTB TM (a bacteriophage-based method) has been studied in parallel with microscopy, standard microbiological culture and in-house IS6110-based PCR methods. A total of 64 samples, including 42 sputum samples and 22 urine samples, were tested in this study. The sensitivity, specificity and overall accuracy values for the FASTPlaqueTB assay relative to that of culture were respectively 76·5, 95 and 90 %. The corresponding values for the in-house IS6110-based PCR assay were 88, 91 and 90 % and, for Ziehl-Neelsen staining, were 59, 95 and 85 %. FASTPlaqueTB gave better clinical performance with urine samples than with sputum samples (sensitivity, specificity and overall accuracy were 100 % with urine samples and 64, 93 and 84 % with sputum samples). The 100 % sensitivity of FASTPlaqueTB was higher than that of the corresponding values for PCR (67 %) with urine samples. In conclusion, FASTPlaqueTB proved to be sensitive, cheap relative to the PCR and rapid. It is able to detect M. tuberculosis in clinical samples within 1 day, reducing the time to diagnosis in comparison with culture.

Fluorescent Reporter DS6A Mycobacteriophages Reveal Unique Variations in Infectibility and Phage Production in Mycobacteria

“…It is unclear if the DS6A-based fluorophage is a better alternative to ⌽ 2 GFP10, considering that the performances of DS6A and ⌽ 2 GFP10 are comparable on laboratory-grown cultures of M. tuberculosis, and that DS6A, in most cases, is relatively less efficient at infecting NTM in comparison to ⌽ 2 GFP10. The second test uses the commercially available FASTPlaque tuberculosis (TB) assay (40) in which D29 phages are used to infect patient samples; extracellular phages are then neutralized, and D29 progeny phages are screened by visualizing plaque formation on lawns of fast-growing M. smegmatis. Although our DS6A fluorophage does not form plaques on lawns of M. smegmatis, these phages could be used to modify this assay and potentially reduce the time to diagnosis from days to hours.…”

Evaluation of rapid techniques for the detection of mycobacteria in sputum with scanty bacilli or clinically evident, smear negative cases of pulmonary and extra-pulmonary tuberculosis

“…Microscopy and culture are generally considered to be the authoritative methods for the laboratory diagnosis of TB. However, smear microscopy is limited due to low sensitivity in paucibacillary specimens (Marei et al 2003). On the other hand, culture remains the gold standard for diagnosis of mycobacterial infections, although it is time consuming and prone to contamination (McNerney 1996, Nancy et al 2000.…”

“…The Mycobacteria Growth Indicator Tube (MGIT) (Becton Dickinson) provides rapid recovery of mycobacteria from clinical specimens (Badak et al 1996). Alternatively, the rapid detection and counting of Mycobacterium tuberculosis complexes from both respiratory and non-respiratory tract specimens may be achieved using the Biotec FASTPlaque TB™ (FPTB) assay (Biotec laboratories ltd, UK), which utilizes a phage amplification technology (Albert et al 2002, Marei et al 2003.…”

Mycobacteriophages: An important tool for the diagnosis of Mycobacterium tuberculosis (Review)

“…The clinical effects of this assay have been evaluated in several countries, including Egypt (27), Pakistan (28), South Africa (29) and Spain (30). Kalantri et al (31) performed a meta-analysis of the detection of M. tuberculosis in clinical samples, based on phage amplification technology in 2005 by examining the literature from databases, including Medline, EMBASE (http://www.elsevier.com/online-tools/embase), Web of Science (http://wok.mimas.ac.uk/) and BIOSIS Previews (http://biosispreviews.isihost.com/).…”