Multiplex polymerase chain reaction for diagnosis of viral and chlamydial keratoconjunctivitis

To develop a multiplex polymerase chain reaction (PCR) for the detection of adenovirus, herpes simplex virus, and Chlamydia trachomatis in conjunctival swabs.

Oligonucleotide primers for detection of the 3 agents were combined in one reaction and evaluated for optimal performance using control DNAs of adenovirus type 2, herpes simplex virus, and C. trachomatis plasmid. The multiplex PCR was evaluated prospectively against its corresponding uniplex PCRs, virus isolation, Chlamydia Amplicor PCR, and an immunoassay technique (immune dot blot test) in a total of 805 conjunctival swabs from patients with suspected viral and chlamydial keratoconjunctivitis.

The multiplex PCR was as sensitive as uniplex PCRs for the detection of the agents in clinical specimens. In the prospective study, 48 of 49 (98%) clinical specimens were positive for adenovirus by the multiplex PCR compared with 26 of 49 (53%) by adenovirus isolation. For herpes simplex virus detection, the multiplex PCR had a sensitivity of 92% (34/37) compared with 94.5% (35/37) by cell culture. The multiplex PCR produced identical results to the Amplicor PCR (21/21; 100%) compared with 71% (15/21) by the immune dot blot test.

With clinical specimens the multiplex PCR was as sensitive as its respective uniplex PCRs but more sensitive than adenovirus isolation and as sensitive as herpes simplex virus isolation or C. trachomatis Amplicor PCR. It has the potential to replace several diagnostic tests with consequent savings in cost. The test also reduces the risk of misdiagnosis by the clinicians.