Application of modern microbiological diagnostic methods for tuberculosis in Macha, Zambia.

Autor: Verweij KE; Medical/Malaria Institute, Macha Hospital, Choma, Zambia. evelyneverweij@gmail.com, Kamerik AR, van Ingen J, van Dijk JH, Sikwangala P, Thuma P, Nouwen JL, van Soolingen D
Jazyk: angličtina
Zdroj: The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease [Int J Tuberc Lung Dis] 2010 Sep; Vol. 14 (9), pp. 1127-31.
Abstrakt: 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.
Databáze: MEDLINE
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