Optimal tuberculosis testing usually involves sputum centrifugation followed by broth culture. However, centrifuges are biohazardous and scarce in the resource-limited settings where most tuberculosis occurs. To optimize tuberculosis testing for these settings, centrifugation of 111 decontaminated sputum samples was compared with syringe-aspiration through polycarbonate membrane-filters that were then cultured in broth. To reduce the workload of repeated microscopic screening of broth cultures for tuberculosis growth, the colorimetric redox indicator 2,3-diphenyl-5-(2-thienyl) tetrazolium chloride was added to the broth, which enabled naked-eye detection of culture positivity. This combination of filtration and colorimetric growth-detection gave similar results to sputum centrifugation followed by culture microscopy regarding mean colony counts (43 versus 48; P = 0.6), contamination rates (0.9% versus 1.8%; P = 0.3), and sensitivity (94% versus 95%; P = 0.7), suggesting equivalency of the two methods. By obviating centrifugation and repeated microscopic screening of cultures, this approach may constitute a more appropriate technology for rapid and sensitive tuberculosis diagnosis in basic laboratories.
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机译：最佳的结核病检测通常包括将痰离心，然后进行肉汤培养。但是，在大多数结核病发生的资源有限的地区，离心机具有生物危害性且稀缺。为了针对这些设置优化结核病检测，将111种去污染的痰样品的离心与通过聚碳酸酯膜滤器的注射器抽吸进行了比较，然后将其在肉汤中培养。为减少重复显微镜检查结核菌生长的肉汤培养物的工作量，将比色氧化还原指示剂2,3-二苯基-5-（2-噻吩基）氯化四唑加入肉汤中，从而可以肉眼检测培养物的阳性。过滤和比色法生长检测的这种组合在痰液离心，培养显微镜下的平均菌落数（43对48; P = 0.6），污染率（0.9％对1.8％; P = 0.3）和敏感性（ 94％和95％; P = 0.7），表明这两种方法相当。通过避免离心和对培养物进行反复的微观筛选，这种方法可能构成在基础实验室中快速，灵敏地诊断结核病的更合适技术。
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