Abstract:

Objective To investigate the diagnostic value of sputum PCR-reverse dot blot (RDB) hybridization in the diagnosis of suspected NTM pulmonary disease.Methods Three hundred and thirty four cases of suspected NTM pulmonary disease were selected from January 2014 to October 2017 at the Shanghai Pulmonary Hospital Affiliated to Tongji University School of Medicine based on respiratory symptoms and thoracic CT findings. Sputum samples were collected and underwent PCR-RDB hybridization Mycobacterium species identification, and traditional PNB-TCH growth culture, 218 patients were diagnosed with NTM pulmonary disease (NTM pulmonary disease group), 42 with tuberculosis (TB group), and 74 with other lung diseases (excluded from the study). The sensitivity, specificity, positive predictive values and conformity rate of PCR-RDB were calculated.Results The positive culture detection rate for the 334 cases of suspected NTM pulmonary disease was 67.66% (226/334), while the PCR-RDB detection rate was 64.67% (216/334). Differences in the results for the two methods were not statistically significant (χ ²=0.67, P=0.231). The sensitivity of PCR-RDB and culture for the 218 cases of NTM pulmonary disease was 82.57% (180/218) and 87.61% (191/218), respectively, and no statistically significant difference between the two methods was found (χ ²=1.20, P=0.169). The positive predictive values for PCR-RDB and culture were 98.36% (180/183) and 100.00% (191/191), respectively. The specificity of PCR-RDB and culture for the 42 cases of TB was 78.57% (33/42) and 83.33% (35/42), respectively, and no statistically significant difference was found (χ ²=0.31, P=0.391).The positive predictive values of PCR-RDB and culture for diagnosing TB were 100.00% (33/33) and 100.00% (35/35), respectively. The conformity rate of PCR-RDB was 83.08% (216/260), and that of culture was 86.92% (226/260), and no statistically significant difference was found (χ ²=1.51, P=0.134). Conclusion Sputum PCR-RDB hybridization has high sensitivity and specificity and is a simple and rapid method that can be used to identify bacteria directly. It is a helpful guide for clinicians during diagnosis and may lead to more rapid and accurate treatment.

Key words: Mycobacteria, atypical, Tuberculosis, pulmonary, Diagnosis, Polymerase chain reaction, Enzyme-linked immunospot assay