Table of Contents

2017 Month : December Volume : 3 Issue : 2 Page : 7-12

RAPID TOOLS- THE NEW ARMAMENTARIUM FOR DIAGNOSIS OF TUBERCULOSIS VS CLASSIC TOOLS

Shavi Nagpal1, Aroma Oberoi2, G. S. Chopra3, S. R. Varghese4, Navjot Singh5, Ashish Chawla6

Corresponding Author:
Dr. Aroma Oberoi,
Professor and HOD,
Department of Microbiology,
Christian Medical College and Hospital,
Ludhiana-141008, Punjab.
E-mail: draromaoberoi@yahoo.com

ABSTRACT

BACKGROUND

Tuberculosis remains amongst deadliest communicable diseases. Number of diagnostic tests are available, but Nucleic acid amplification techniques, the new armamentarium for diagnosis are rapid and sensitive. The aim of this study is to compare such rapid diagnostic tests with conventional culture method and AFB smear examination.

MATERIALS AND METHODS

Total of 895 clinical samples (July 2015 to April 2017) were processed using smear microscopy, culture on LJ medium and real time PCR. Additionally, few samples were subjected for liquid culture (MGIT) and cartridge based nucleic acid amplification test (CBNAAT).

RESULTS

Out of 895 samples [including 72 pulmonary samples (8.05%) and 823 (91.95%) extrapulmonary] tested, smear microscopy was positive in 22 samples (2.45%), while culture was positive for 37 samples (4.13%). The TB PCR results were positive in 206 (23.00%) samples out of 895. MGIT (used in 75 samples) was positive in 21.33% samples (16 out of 75). CBNAAT was used on 50 PCR positive samples and was positive in 46 samples.

CONCLUSION

Conventional methods remain the gold standard for diagnosing pulmonary TB; however, poor performance of these on extrapulmonary samples and delayed diagnostic times demand for more rapid and sensitive nucleic acid amplification techniques. The major advantage of CBNAAT in simultaneously detecting Rifampicin resistance is especially beneficial in patients with MDR and HIV associated TB. Also, MGIT proved to be a valuable alternative to solid culture in terms of earlier detection. But for maximum recovery of Mycobacteria, both conventional and rapid methods should be incorporated.

KEYWORDS

Tuberculosis (TB), Ziehl-Neelsen (ZN), Lowenstein-Jensen (LJ) Medium, Polymerase Chain Reaction (PCR), Mycobacterium Growth Indicator Tube (MGIT), Cartridge Based Nucleic Acid Amplification Test (CBNAAT)/ Xpert MTB/RIF.

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