Abstract
Purpose:
To highlight the role of RT- PCR in the detection of active Mycobacterium tuberculosis (M tb) infection in patients with endophthalmitis helping in early initiation of treatment and its agreement with Acid Fast stain (AFS), mMGIT (BACTEC culture), nested PCR (nPCR) and Real Time PCR techniques
Methods:
Patients with microbiologically proven diagnosis of tuberculous endophthalmitis were studied (n=4).Vitreous and aqueous aspirates were subjected to AFS by Ziehl-Neelson stain (n=4), RT-PCR using two sets of primers for the 261 kb region of the 85B gene (n=4), Quantitative real time PCR targeting IS6110 using Genosen’s real time PCR (n=3), nested PCR targeting MPB64 gene and IS6110 region (n=4) and culture by BACTEC method for M tb (n=4)
Results:
Four young patients (22-36 years old) were found to have tuberculous endophthalmitis. Three patients presented primarily with ocular complaints and no previous history of systemic tuberculosis. All patients underwent vitrectomy and were treated with anti- tuberculosis treatment based on RT-PCR reports. There was 100 % concordance between the RT-PCR and AFS. M tb culture was positive in 3 of 4 patients with positive RT-PCR for M tb. There was also 100% concordance between nPCR and RT-PCR. Real time PCR done in 3 patients was in agreement with RT-PCR and AFS
Conclusions:
RT-PCR is an accurate diagnostic test for active tuberculous endophthalmitis. We believe that the detection of mRNA using RT- PCR as a surrogate of viable M.tb from vitreous biopsy is of immense significance in initiation of early systemic treatment in these otherwise unsuspected M.tb infection of eye and has hitherto not been reported. To the best of knowledge this is the first report of isolation of M. tuberculosis from vitreous aspirate
Keywords: 513 endophthalmitis •
433 bacterial disease