Abstract:

Objective To evaluate the application value of thermostatic microfluidic system in detection and identification of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM). Methods A total of 624 sputum specimens positive in acid-fast staining were collected from the Eighth Affiliated Hospital of Xinjiang Medical University from September 2018 to December 2019. Roche solid culture, p-nitrobenzoic acid (PNB) and thiophene-2-carboxylic acid hydrazine (TCH) growth test, and constant temperature microfluidic system were used for mycobacterial detection and strain identification; bacterial species identification results of Roche solid culture and PNB/TCH growth test were used as reference to evaluate the efficiency of the thermostatic microfluidic system in detecting mycobacteria and identifying bacterial species. Results Among 624 sputum samples, 612 (98.1%) were positive using Roche solid culture, and 607 (97.3%) were positive by thermostatic microfluidic system. The difference was not statistically significant (χ²=0.021, P=0.950). Using the results of Roche solid culture method as the standard, the sensitivity and specificity of the thermostatic microfluidic system for detecting mycobacteria in sputum samples with positive acid-fast staining were 99.2% (607/612) and 100.0% (12/12), respectively, the Kappa value was 0.82. Using the results of the PNB/TCH growth test as the standard, the sensitivity and specificity of the thermostatic microfluidic system for detecting MTBC in sputum samples were 99.6% (513/515) and 100.0% (97/97), respectively, and the Kappa value was 0.99; the sensitivity and specificity of the thermostatic microfluidic system for detecting NTM in sputum samples were 96.9% (94/97) and 100.0% (515/515), respectively, and the Kappa value was 0.98. Conclusion The thermostatic microfluidic system has good performance in identifying MTBC and NTM in sputum specimens when based on acid-fast staining.

Key words: Mycobacterium tuberculosis, Mycobacteria,atypical, Nucleic acid amplification techniques, Diagnosis,differential, Evaluation studies