Polymerase chain reaction for DNA detection from ocular fluids in patients with various types of choroiditis in a referral eye center in India.

AIMS

The aim of this study was to detect Mycobacterium tuberculosis (MTB) DNA with polymerase chain reaction (PCR) in aqueous or vitreous samples of patients suffering from choroiditis presumed to be infectious origin.

SETTINGS AND DESIGN

Hospital-based, retrospective case-control study.

SUBJECTS AND METHODS

In all, forty eyes of forty patients with choroiditis divided into two groups - Group A (serpiginous-like choroiditis, ampiginous choroiditis, multifocal choroiditis) and Group B (choroidal abscess, miliary tuberculosis (TB), choroidal tubercle) were analyzed retrospectively. In 27 controls (patients without uveitis undergoing phacoemulsification), anterior chamber aspirate was done and sample subjected to real-time PCR. Patients underwent nested PCR for MTB using IS6110 and MPB64 primers from aqueous (n = 39) or vitreous (n = 1). All patients underwent detailed ophthalmological examination by slit-lamp biomicroscopy, fundus examination by indirect ophthalmoscopy, and fundus photograph and fundus fluorescein angiography if required.

STATISTICAL ANALYSIS

Positive results of PCR for MTB within the group and between two groups were statistically analyzed using Chi-square test.

RESULTS

There were 25 males and 15 females. Mean age at presentation was 34.66 years (range, 14-62). PCR positivity rates were 41.3% (n = 12/29) and 81.82% (n = 9/11) in Groups A and B, respectively. No controls had PCR-positive result. Comparison of PCR positivity rates showed statistically significant difference between Groups A and B (P = 0.028). Systemic TB was detected in 57.14% (n = 12/21) of all PCR-positive cases (Group A - 33.3%, n = 4/12; Group B - 88.9%, n = 8/9). Systemic antitubercular treatment (ATT) for 9 months and oral steroids were successful in resolution of choroiditis in all PCR-positive patients (n = 21) without disease recurrence.

CONCLUSIONS

Eyes with choroiditis of suspected/presumed tubercular origin should be subjected to PCR for diagnosis of TB and subjected to ATT for prevention of recurrences.