DOI: http://dx.doi.org/10.18203/2349-3933.ijam20190507

Improved sensitivity of direct microscopy for Mycobacterium tuberculosis in lymph nodes: comparison of fluorescent microscopy and modified bleach method ZN microscopy along with conventional ZN staining method

Gul Aalmeen, Sangeeta Sharma, Sneha Vishwasrao, Rani Bansal, Anjali Khare

Abstract


Background: Extra pulmonary tuberculosis arises as a result of lymphatic spread from a primary focus. Fine needle aspiration cytology has assumed an important role in the evaluation of peripheral lymphadenopathy as a possible minimally invasive alternative to excisional biopsy. In most low-income countries; the only practically available bacteriologic method for diagnosing EPTB is direct smear microscopy for acid fast bacilli from the sample of the lesion. There are various methods of staining and concentration for improving sensitivity of direct microscopy for detection of tubercle bacilli in specimen.

Methods: This prospective study was carried out in the Department of Pathology, Subharti Medical College and associated Chattrapati Shivaji Subharti Hospital, Meerut for a period of 2 years from July 2016 - August 2018 in 151 patients with clinical suspicion of TB and significant lymphadenopathy.

Results: AFB positivity increased from 40.39% on conventional ZN stain to 48.34% on modified bleach method ZN stain and to 56.29% on Auramine-O fluorescent stain. Taking fluorescent microscopy (Auramine-O) as reference method the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of conventional ZN stain and modified bleach method ZN stain were calculated as 71.8%, 100%, 100%, 73.33%, 84.10% and 85.33%,100%,100% ,84.61% ,92.05%, respectively.

Conclusions: The addition of fluorescent microscopy (Auramine-O) and modified bleach method ZN microscopy along with conventional ZN staining method would be an important adjunct to improve the microscopic detection of Mycobacterium tuberculosis in fine-needle aspirates of lymph nodes.


Keywords


Auramine-O stain, Acid fast bacilli, Bleach modified ZN stain, Convention Ziehl-Neelson stain, Extra pulmonary tuberculosis, Fine needle aspiration cytology

Full Text:

PDF

References


Krishna M, Gole SG. Comparison of conventional Ziehl-Neelsen method of acid fast bacilli with modified bleach method in tuberculous lymphadenitis. J Cytol. 2017; 34(4):188-92.

Kochhar AK, Patel KB, Shah M. Pattern of lymphadenopathy on fine needle aspiration cytology of superficial lymph nodes (a study of 150 cases). J Adv Res Biol Sci. 2012;4:288-92.

Pakalpaty S, Lakshmi GSR, Jahnavi I, Nagamani K, Prashanthi K, Soujanya KN, et al. A Study of Early and Accurate Detection of Mycobacterium tuberculosis among meningitis cases by using conventional saining methods. Acta Biomedica Scientica. 2017;4(2):1-5.

Khubnani H, Munjal K. Application of bleach method in diagnosis of extra-pulmonary tuberculosis. Indian J Pathol Microbiol. 2005 Oct;48(4):546-50.

Joshi P, Singh M, Bhargava A, Singh M, Mehrotra R. Autofluorescence-an important ancillary technique for the detection of Mycobacterium tuberculosis: revisited. Diag Cytopathol. 2013 Apr;41(4):330-4.

Thakur B, Mehrotra R, Nigam JS. Correlation of various techniques in diagnosis of tuberculous lymphadenitis on fine needle aspiration cytology. Pathol Res Int. 2013;1-4.

Farnia P, Mohammadi F, Zarifi Z, Tabatabee DJ, Ganavi J, Ghazisaeedi K, et al. Improving sensitivity of direct microscopy for detection of acid-fast bacilli in sputum: use of chitin in mucus digestion. J Clin Microbiol. 2002 Feb 1;40(2):508-11.

Gong G, Lee H, Hoon Kang G, Shim YH, Huh J, Kwang Khang S. Nested PCR for diagnosis of tuberculous lymphadenitis and PCR‐SSCP for identification of rifampicin resistance in fine‐needle aspirates. Diag Cytopathol. 2002 Apr;26(4):228-31.

Aung WW, Nyein MM, Ti T, Maung W. Improved method of direct microscopy for detection of acid-fast bacilli in sputum. Southeast Asian J Trop Med Public Health. 2001;32(2):390-3.

Rioki JN, Ndungu J, Rogena EA, Jaoko W. Comparative evaluation of direct Ziehl-Neelsen (ZN) smear and modified ZN against fluorescent technique in the detection of acid-alcohol fast bacilli in lymph node aspirates. East Africa J Pathol. 2014;1:19-22.

Dhawan I, Gupta O, Kaushik A, Ranga S, Kasana D, Gupta PK. Cytomorphological spectrum and Ziehl-Nelson staining in suspected tuberculous lymphadenitis: A study of 100 cases. Ann Pathol Lab Med. 2015 Feb 6;2(1):A36-41.

Khare M, Kaushal M. Utility of modified bleach method technique for the demonstration of acid fast bacilli in the diagnosis of tuberculous lymphadenopathy in comparison to routine Ziehl-Neelsen staining. Ann Pathol Lab Med. 2016; 3(4);329-32.

Gangane N, Anshu, Singh R. Role of modified bleach method in staining of acid-fast bacilli in lymph node aspirates. Acta Cytol. 2008;52(3):325-28.

Bhardwaj S, Kashyap I, Kumari R. Comparative evaluation of two staining techniques for detection of Tubercular bacilli in lymph nodal aspirates. Int J Health Sci Res. 2015;5(7):115-21.

Annam V, Kulkarni MH, Puranik RB. Comparison of the modified fluorescent method and conventional Ziehl-Neelsen method in the detection of acidfast bacilli in lymphnode aspirates. Cyto J. 2009;6-13.

Patel MM, Patel K, Italiya SL, Kaptan KR. Improved diagnosis of tuberculosis in lymph node cytology by bleach method for detection of acid fast bacilli in comparison to conventional Ziehl Neelsen staining method. Int J Med Sci Public Health. 2013;2(4):935-39.

Dwivedi G, Mathur C. Modified bleach method – improving microscopic detection of acid fast bacilli in fine needle aspiration smears of lymph nodes. JMSCR. 2013;1(4):176-81.

Akhter S, Fernandes H, Goyal G. Comparision of auramine-O stain with Ziehl Neelson stain in suspected cases of tubercular lymphadenitis. Int J Recent Trends Sci Technol. 2015;15(3):524-5.

Krishna M, Kumar A. Tuberculous mycobacteria bacilli fluorescence and compare with Ziehl-Neelsen stain in fine-needle aspiration cytology of tubercular lymphnode. Int J Otorhinolaryngol Head Neck Surg. 2016 Apr 8;2(2):66-9.

Arora B, Arora DR. Fine needle aspiration cytology in diagnosis of tuberculous lymphadenitis. Indian J Med Res. 1990;91:189-92.