Fluorescein diacetate vital staining allows earlier diagnosis of rifampicin-resistant tuberculosis
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.
Available from: PubMed Central
- "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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ABSTRACT: Culturing Mycobacterium tuberculosis remains the gold standard for the laboratory diagnosis of pulmonary tuberculosis, with 9 million new cases and 1.5 million deaths mainly in developing countries. Reviewing data reported over 20 years yields a state-of-the-art procedure for the routine culture of M. tuberculosis in both developed and developing countries. Useful specimens include sputum, induced sputum, and stools collected in quaternary ammonium preservative-containing sterile cans. The usefulness of other non-invasive specimens remains to be evaluated. Specimens can be collected in a diagnosis kit also containing sampling materials, instructions, laboratory requests, and informed consent. Automated direct LED fluorescence microscopy after auramine staining precedes inoculation of an egg-lecithin-containing culture solid medium under microaerophilic atmosphere, inverted microscope reading or scanning video-imaging detection of colonies and colonies identification by recent molecular methods. This procedure should result in a diagnosis of pulmonary tuberculosis as fast as 5 days. It may be implemented in both developed and developing countries with automated steps replaceable by manual steps depending on local resources.
Frontiers in Microbiology 11/2015; 6. DOI:10.3389/fmicb.2015.01184 · 3.99 Impact Factor
Available from: Ioana Diana Olaru
- "In this method intracellular accumulation of fluorescein occurs in cells with preserved membrane integrity marking cell viability . Fluorescein diacetate vital staining has been used in patients with delayed smear conversion to identify cases of treatment failure earlier . In contrast to sputum smear microscopy and molecular methods culture results are not immediately available. "
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ABSTRACT: Sputum smear microscopy is widely used for tuberculosis diagnosis and treatment monitoring. We evaluated the correlation between smear microscopy and time to liquid culture positivity during early tuberculosis treatment. The study included patients with smear-positive pulmonary tuberculosis hospitalized at a tuberculosis reference centre in Germany between 01/2012 and 05/2013. Patient records were reviewed and clinical, radiological and microbiological data were analysed. Sputum samples were collected before treatment initiation and weekly thereafter. A number of 310 sputum samples from 30 patients were analysed. Time to liquid culture positivity inversely correlated with smear grade (Spearman's rho -0.439, p<0.001). There was a better correlation within the first two months vs. after two months of therapy (-0.519 vs. -0.416) with a trend to a more rapid increase in time to positivity between baseline and week 2 in patients who culture-converted within the first two months (5.9 days vs. 9.4 days, p = 0.3). In conclusion, the numbers of acid-fast bacilli in sputum smears of patients with pulmonary tuberculosis and time to culture positivity for M. tuberculosis cultures from sputum are correlated before and during tuberculosis treatment. A considerable proportion of patients with culture conversion after two months of therapy continued to have detectable acid-fast bacilli on sputum smears.
PLoS ONE 08/2014; 9(8):e106075. DOI:10.1371/journal.pone.0106075 · 3.23 Impact Factor
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ABSTRACT: Tuberculosis (TB) has scourged humankind for millennia, and latent infection affects nearly one-third of today's world population. The emergence of multidrug-resistant (MDR)-TB is a major global threat and reflects treatment failure of drug-sensitive disease. MDR-TB management is a burden for patients and society; success rates are unacceptably low with prolonged treatment duration. Mycobacterium tuberculosis (Mtb) possesses the ability to transform into a dormant state in which it can persist in the face of antimicrobial treatment and host defense. This sub-population of persisters is largely responsible for lengthy and difficult treatment. Targeting persistent bacilli could eventually improve the treatment success rate (currently 50-65 %) and shorten duration of treatment. A subset of therapies in the pipeline, termed therapeutic vaccines, use the host immune response to attack Mtb. The historical occurrence of an exacerbated host response has resulted in a negative perception of therapeutic vaccines. Thus, a renewed concept of immunotherapy is needed. We review current perspectives of immunotherapy in MDR-TB based on the knowledge of TB immunology and briefly discuss the profiles of several therapeutic vaccine products.
Medical Microbiology and Immunology 11/2012; 202(2). DOI:10.1007/s00430-012-0278-6 · 3.04 Impact Factor
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