Abstract:

Objective To explore the application value of intracellular acid-fast staining in the detection of Mycobacterium tuberculosis (TB) in body fluid specimens.Methods A total of 1236 body fluid specimens were collected from the patients who were suspected to have TB and sought health care at Xi’an Chest Hospital from April 2013 to April 2015, including 237 cerebrospinal fluid specimens and 999 pleural effusion and ascites specimens. The tests for detection of Mycobacterium tuberculosis were performed to the above samples by using the following methods: acid fast staining of Mycobacterium tuberculosis in leukocytes (modified acid-fast staining method or intracellular staining method), BACTEC MGIT 960 liquid culture of Mycobacterium tuberculosis (MGIT 960 liquid culture method) and polymerase chain reaction (PCR) fluorescence probe method (PCR method).Results As for the pleural effusion specimens, the sensitivity (18.52%, 160/864) and the positive rate (16.02%, 160/999) were found to be the highest ones by using the MGIT 960 liquid culture method, followed by using the intracellular staining method (sensitivity 13.66%, 118/864; positive rate 11.81%, 118/999), the sensitivity (6.94%, 60/864) and the positive rate (6.01%, 60/999) were the lowest ones by using the PCR method. The positive rate by using the intracellular staining method was significantly different from that by using the MGIT 960 liquid culture method and the PCR method ( {\chi }_{960}^2 =10.26, {\chi }_{\mathrm{PCR}}^2 =29.00; P<0.01). For the cerebrospinal fluid specimens, the sensitivity (22.15%, 35/158) and the positive rate (14.77%, 35/237) were the highest ones by using the intracellular acid-fast staining method, followed by using the MGIT 960 liquid culture method (sensitivity 12.03%, 19/158; positive rate 8.02%, 19/237) and the lowest ones were found by using the PCR method (sensitivity 3.16%, 5/158; positive rate 2.11%, 5/237). The positive rate by using the intracellular staining method was significantly higher than that by using the MGIT 960 liquid culture method and the PCR method ( {\chi }_{960}^2 =5.36, P=0.020; {\chi }_{\mathrm{PCR}}^2 =23.36, P=0.020). Conclusion Mycobacterium tuberculosis intracellular acid-fast staining method is very important in detection of Mycobacterium tuberculosis in the body fluid specimens, and it is an economic, simple, achieving the expected positive rate test method.

Key words: Mycobacterium tuberculosis, Staining and labeling, Diagnostic techniques and methods, Comparative study, Data interpretation, statistical