Detection of Mycobacterium tuberculosis in corneas from donors with active tuberculosis disease through polymerase chain reaction and culture

Abstract

Objective: To determine if Mycobacterium tuberculosis can be detected in corneas of donors who have active tuberculosis (TB) disease using polymerase chain reaction (PCR) or culture.

Design: This is a prospective cross-sectional study.

Participants: 25 corneas (12 from TB-negative donors and 13 from TB-positive donors) from the Sta. Lucia International Eye Bank were submitted to the TB Research Laboratory, Medical Research Laboratory, Department of Medicine, UP-PGH, for diagnostic evaluation.

Intervention: Corneas were evaluated using PCR test for M tuberculosis. Acid-fast bacilli smear and culture were also done.

Main outcome measures: Result of laboratory findings.

Results: Among 12 TB-negative donors, there were 2 (16.67%) corneas that were PCR negative for M tuberculosis, whereas 10 (83.33%) corneas were PCR positive for M tuberculosis. Among 13 TB-positive donors, there were 7 (53.85%) corneas that were PCR negative for M tuberculosis, whereas 6 (46.15%) corneas were PCR positive for M tuberculosis. All cultures were negative.

Conclusion: PCR for M tuberculosis was positive for some TB-positive donors as well as TB-negative donors. However, all cultures were negative. It is recommended that further studies be done to investigate if recipients with PCR-positive corneas will eventually lead to disease transmission or not. It is further recommended that such findings be used to re-evaluate criteria for suitability of donors with tuberculosis.