Department of Pathology, Apollo Hospitals, Hyderabad, Telangana, India.
Department of Microbiology, Apollo Hospitals, Hyderabad, Telangana, India.
Indian J Med Res. 2023 Jan;157(1):81-86. doi: 10.4103/ijmr.IJMR_2239_19.
BACKGROUND & OBJECTIVES: Tuberculosis, most commonly caused by Mycobacterium tuberculosis (MTB), is an infectious bacterial disease, with a major impact on global health. In this study, immunohistochemistry (IHC), acid-fast bacilli (AFB) culture and Ziehl-Neelsen (ZN) staining, techniques were compared on bronchoalveolar lavage (BAL) and bronchial washings (BW) with respect to sensitivity and specificity for detecting mycobacteria, taking culture as the gold standard.
Consecutive BAL and BW specimens were included in the study, over a period of one year for which AFB cultures were available. Samples with diagnosis other than inflammatory pathology such as malignancies or inadequate samples were excluded. A total of 203 BAL and BW specimens from patients with age ranging from 14 to 86 yr were analyzed for the presence of mycobacteria. The utility and efficacy of ZN stain and IHC in detecting mycobacteria was tested using AFB culture as a gold standard.
Out of 203 cases, 10.3 per cent (n=21) were positive on AFB culture. Of these, 5.9 per cent (n=12) smears were positive for ZN stain, whereas IHC positivity was seen in 8.4 per cent (n=17) of the cases. ZN staining had a sensitivity of 57.1 per cent and a specificity of 100 per cent whereas, IHC had a sensitivity of 81 per cent and a specificity of 81.9 per cent.
INTERPRETATION & CONCLUSIONS: Comparison with AFB culture (gold standard), IHC was found to be superior to ZN stain in terms of sensitivity, whereas ZN stain was found to be superior to IHC in terms of specificity. These findings therefore suggest that IHC may be a useful adjunct to ZN stain in the detection of mycobacteria in specimens from the respiratory tract.
结核病最常见的病因是结核分枝杆菌（MTB），是一种传染性细菌性疾病，对全球健康有重大影响。本研究比较了支气管肺泡灌洗液（BAL）和支气管冲洗液（BW）中免疫组织化学（IHC）、抗酸杆菌（AFB）培养和齐-尼染色（ZN）三种方法检测分枝杆菌的敏感性和特异性，以培养为金标准。
连续纳入研究一年期间 BAL 和 BW 标本，在此期间可进行 AFB 培养。排除诊断为恶性肿瘤或样本不足等炎症性病变以外疾病的标本。分析了 203 例年龄在 14 至 86 岁之间的 BAL 和 BW 标本中是否存在分枝杆菌。以 AFB 培养为金标准，测试 ZN 染色和 IHC 检测分枝杆菌的效用和效果。
203 例患者中，10.3%（n=21）AFB 培养阳性。其中，5.9%（n=12）涂片 ZN 染色阳性，而 IHC 阳性见于 8.4%（n=17）的病例。ZN 染色的敏感性为 57.1%，特异性为 100%，而 IHC 的敏感性为 81%，特异性为 81.9%。
与 AFB 培养（金标准）比较，IHC 在敏感性方面优于 ZN 染色，而 ZN 染色在特异性方面优于 IHC。因此，这些发现表明 IHC 可能是 ZN 染色检测呼吸道标本中分枝杆菌的有用辅助手段。
