Fluorescein diacetate vital staining allows earlier diagnosis of rifampicin-resistant tuberculosis
ABSTRACT 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.
SourceAvailable from: PubMed CentralClinical Infectious Diseases 12/2014; DOI:10.1093/cid/ciu1153 · 9.42 Impact Factor
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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 · 3.53 Impact Factor
Clinical Infectious Diseases 12/2014; DOI:10.1093/cid/ciu1156 · 9.42 Impact Factor