Fluorescein diacetate vital staining allows earlier diagnosis of rifampicin-resistant tuberculosis

Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium.
The International Journal of Tuberculosis and Lung Disease (Impact Factor: 2.32). 06/2012; 16(9):1174-9. DOI: 10.5588/ijtld.11.0166
Source: PubMed


Damien Foundation Project, Bangladesh.
To evaluate sputum smear fluorescein diacetate (FDA) vital staining to predict culture-defined failure and rifampicin (RMP) resistance.
A retrospective, operational study.
A total of 1633 episodes of auramine smear-defined late conversion and failure could be evaluated (respectively 640 and 584 on first treatment and 185 and 224 on retreatment). Negative FDA was 95% predictive of negative culture in patients on first treatment, while its positive predictive value was around 95% during retreatment. The predictive value of a positive (not scanty) result for RMP resistance or environmental non-tuberculous mycobacteria (NTM) was at least 90%, except in late converters on first-line treatment; a negative result was over 95% exclusive of the same except in retreatment failures. FDA correctly identified 88-98% of all RMP resistance.
FDA staining increased the proportion of tuberculosis patients put on second-line treatment without receiving the standard first-line retreatment regimen. In our setting, with excellent microscopy, late case presentation and low resistance prevalence, it proved indispensable for efficient culture and referrals of early suspects for rapid drug susceptibility testing (DST). In other settings with low prevalence of NTM and difficult access to accurate and rapid DST, FDA-positive failures might even be considered for immediate start of second-line treatment.

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    • "LED-FM reduces observation time by 50–75% (Ba and Rieder, 1999; Marais et al., 2008; Habtamu et al., 2012; Table S3), increases sensitivity (Table S4; Steingart et al., 2006; Marais et al., 2008; Trusov et al., 2009; World Health Organization, 2011; Marzouk et al., 2013) for an estimated 1.97 ± 0.71$ cost lower than the 2.20 ± 0.58$ cost of Ziehl-Neelsen staining (Xia et al., 2013). LED-FM detection of esterase activity specific for viable M. tuberculosis cells (Hamid Salim et al., 2006; Van Deun et al., 2012; Datta et al., 2015) unfortunately had limited specificity and sensitivity (Lawn and Nicol, 2015). Promisingly, several computational algorithms recognize Ziehl–Neelsen stained acid-fast bacilli in digitalized images. "
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    • "In this method intracellular accumulation of fluorescein occurs in cells with preserved membrane integrity marking cell viability [23]. Fluorescein diacetate vital staining has been used in patients with delayed smear conversion to identify cases of treatment failure earlier [24]. In contrast to sputum smear microscopy and molecular methods culture results are not immediately available. "
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