Isolation of Diverse Mycobacterium Tuberculosis Strains Employing Automated and Conventional Culture from Lymphadenitis in a Tertiary Care Center, Pondicherry, India Kandhakumari Gandhi 1 , Stephen Selvaraj 2* , Kavitha Kannaiyan 3 1 Department of Microbiology, Kanti Devi Medical College and Research Centre, Mathura, Uttar Pradesh, India 2 Department of Microbiology, Mahatma Gandhi Medical College & Research Institute, Sri Balaji Vidyapeeth (Deemed-to-be-University), Pondicherry, India 3 Department of Microbiology, Aarupadai Veedu Medical College and Hospital, Pondicherry, India ABSTRACT In India, tuberculosis remains a major public health problem and Tuberculous lymphadenitis remains a diagnostic challenge. This study aimed to isolate M. tuberculosis from lymphadenitis employing LJ and MGIT culture. A total of 49 single clinical specimens collected from patients with clinical suspicion of Tuberculous lymphadenitis were included. Ziehl- Neelsen microscopy and culture was performed and growth of M. tuberculosis was identified using standard tests. Drug susceptibility testing was carried out in MGIT and the isolated M. tuberculosis strains causing lymphadenitis were genotyped by spoligotyping. Among 49 samples processed, 28.6% were positive by ZN, 20.4% on LJ and 26.7% in MGIT. LJ and MGIT together yield 32.7% positivity. The mean and median turnaround time for LJ and MGIT culture was 31.8 and 14.5 days respectively. Conventional identification tests identified 15 M. tuberculosis strains and one M. bovis BCG. Drug susceptibility revealed 50% isolates were resistant to one or more drugs, but not MDR-TB. Spoligotyping revealed 47% of the strains causing lymphadenitis were profiles described as orphans. To conclude, inclusion of both LJ and MGIT increases percentage positivity. The short Turn Around Time (TAT) of MGIT helps early reporting of drug susceptibility thus avoiding empirical treatment, in areas where molecular techniques are not feasible. Orphan spoligotype is associated with lymphadenitis. Key words: M. tuberculosis, Lymphnode, Lowenstein Jensen, MGIT960, Lymphadenitis HOW TO CITE THIS ARTICLE: Kandhakumari Gandhi, Stephen Selvaraj, Kavitha Kannaiyan, Isolation of Diverse Mycobacterium Tuberculosis Strains Employing Automated and Conventional Culture from Lymphadenitis in a Tertiary Care Center, Pondicherry, India , J Res Med Dent Sci, 2019, 7(3): 164-168 Corresponding author: Stephen Selvaraj e-mail✉: stephens4950@gmail.com Received: 18/05/2019 Accepted: 30/06/2019 INTRODUCTION In developing countries like India where the incidence of Tuberculosis (TB) is high, TB of the lymph node (Tuberculous lymphadenitis) remains the most common form infecting 30%-52% among extrapulmonary tuberculosis cases [1]. Lymph node tuberculosis occurs due to lymphatic dissemination of Mycobacterium tuberculosis. The infected lymph nodes in the later stage may break open discharging pus and ultimately the wound will not heal for several years. Lymphadenitis is very common in childhood and commonly reported from females when compared to the male. But today lymphadenitis has been reported from people between the age group of 20 years to 40 years [2]. Various conditions like viral or bacterial adenitis, fungal disease, toxoplasmosis, cat scratch fever, carcinoma and other conditions present the same cytology or histopathology that mimics granulomatous lymphadenopathy. These require the differential diagnosis to distinguish them from Tuberculous lymphadenitis. Presence of acid fast bacilli (AFB) in smear and isolation of M. tuberculosis from lymphadenitis pus is the standard diagnostic method [3]. Due to limitations with conventional diagnostic techniques and extensive differential diagnosis, conditions like Tuberculous lymphadenitis need a diagnostic tool which is highly sensitive and specific. Smear microscopy is less sensitive and in developing countries like India, Lowenstein-Jensen (LJ) culture remains the gold standard, although it is time consuming. However automated liquid culture systems like Mycobacterium Growth Indicator Tube (MGIT 960) have been reported to have better sensitivity with short turnaround time compared to solid culture. Spacer oligonucleotide typing (Spoligotyping) is a polymerase chain reaction (PCR)-based genotyping method which detects and differentiates strains of Journal of Research in Medical and Dental Science 2019, Volume 7, Issue 3, Page No: 164-168 Copyright CC BY-NC 4.0 Available Online at: www.jrmds.in eISSN No.2347-2367: pISSN No.2347-2545 JRMDS J o u r n a l o f R e s e a r c h i n M e d i c a l a n d D e n t a l S c i e n c e Journal of Research in Medical and Dental Science | Vol. 7 | Issue 3 | June 2019 164