Culture and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) Proven Mycobacterium Tuberculosis
Ekta Rishi1, Pukhraj Rishi1, K Lily Therese2
1a Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation , Chennai , India.
Purpose:
To report early confirmation of Mycobacterium tuberculosis (MTB) endophthalmitis by detection of 85B mRNA in vitreous by a reverse transcriptase polymerase chain reaction (RT-PCR) technique.
Methods:
Retrospective, interventional case series of 5 patients with MTB endogenous endophthalmitis. Vitreous aspirate was subjected to Ziehl-Neelsen (ZN) staining, BACTEC MicroMGIT culture, RT-PCR targeting the 85B gene, real-time PCR targeting the IS6110 region, and nested PCR targeting the MPB64 gene and IS6110 region. Correlation between detection of MTB RNA, culture positivity, and ZN staining was studied.
Results:
Five patients with endophthalmitis with no history of tuberculosis revealed acid-fast bacilli on ZN staining of vitreous. RT-PCR detected 85B RNA within 24 h. Culture for MTB was positive in 3/5 patients after 1 month. None of the eyes recovered any useful vision.
Conclusions:
RT-PCR can detect viable MTB RNA and provide evidence of active infection much earlier than culture.
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