Background and Aim: Chlamydia trachomatis is an obligate intracellular parasite responsible for ocular and genital infections in human. Chlamydia trachomatis is the most common cause of chronic follicular conjunctivitis and is also responsible for 20% of acute conjunctivitis cases. As a rapid diagnosis is important in the reducing the long-term squeal of the diseases, the objective of this study was to compare three methods including direct immunofluorescence (DIF) method, Giemsa staining and PCR for detection of chlamydia trachomatis in patients with follicular conjunctivitis referred to Farabi hospital in 1392.

 Material and methods: Conjunctival scraping (n=90) was obtained from patients who were referred to the diagnostic laboratory of Farabi hospital during 2012. Smears were prepared by rolling half the swab on to the center of a glass slide. Smears were fixed and used for direct immunofluorescence (DIF) method using a genus specific fluorescein isothiocyanate labelled chlamydia monoclonal antibody. In Giemsa stain, diagnosis was based on the presence of inclusions that were basophilic and stained pinkish-blue. PCR amplification after Extraction performed using CT1 and CT5 primers designed from Omp1 gene.

Results: From the 90 patients examined for Chlamydia trachomatis in the eyes, 28 (31.1%) were positive by DIF and 13 (14.4%) by Giemsa staining; and 35 patients (38.8%) showed positive results in PCR. Sensitivity, specificity, positive predictive value and negative predictive value of DIF in comparison to PCR respectively were calculated as 88.33, 100, 100 and 88.70. Sensitivity, specificity, positive predictive value and negative predictive value of DIF in comparison to PCR respectively were calculated as 61.40, 100, 100 and 71.42. Therefore, sensitivity and negative predictive value of DIF are significantly higher than Giemsa staining.

Conclusion: According to results of this study, DIF is more sensitive and more reliable than Giemsa staining for detection of Chlamydia trachomatis in the conjunctiva samples of patients with follicular conjunctivitis.