1. Application of modern microbiological diagnostic methods for tuberculosis in Macha, Zambia.
- Author
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Verweij KE, Kamerik AR, van Ingen J, van Dijk JH, Sikwangala P, Thuma P, Nouwen JL, and van Soolingen D
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Bacteriological Techniques, Benzophenoneidum, Cross-Sectional Studies, Female, Humans, Male, Microscopy, Fluorescence, Middle Aged, Sensitivity and Specificity, Staining and Labeling methods, Tuberculosis microbiology, Young Adult, Zambia, Mycobacterium tuberculosis isolation & purification, Sputum microbiology, Tuberculosis diagnosis
- Abstract
Setting: Macha, Zambia., Objective: To assess the benefits of auramine-O staining fluorescence microscopy and Mycobacterial Growth Indicator Tube (MGIT) liquid culture with molecular identification in tuberculosis (TB) diagnostics., Design: One hundred patients suspected of TB were subjected to three sputum sample examinations applying Ziehl-Neelsen (ZN) and auramine-O staining and MGIT culture. Positive cultures were identified using the GenoType CM assay; cultures identified as Mycobacterium tuberculosis complex were the gold standard for a diagnosis of TB., Results: The 100 patients produced 271 sputum samples; of these, 30 patients had positive cultures. M. tuberculosis complex bacilli were isolated in 17 (56.7%) patients, non-tuberculous mycobacteria (NTM) in 11 (36.7%) and other acid-fast bacilli in two. Forty-eight samples (17.7%) were contaminated. Auramine-O detected 16 (57.1%) patients culture-positive for mycobacteria and 12 patients with culture-proven TB, vs. respectively 8 (28.6%, P = 0.008) and 7 (41.2%, P = 0.044) for ZN. Three of eight auramine-positive/ZN-negative patients were culture-positive for NTM only., Conclusion: The auramine-O method significantly increases sensitivity, although the higher NTM detection rate implies that this does not in itself lead to a more accurate diagnosis of TB. MGIT culture is highly sensitive, although contamination rates were a drawback; the high frequency of NTM isolation warrants a robust identification method.
- Published
- 2010