Molecular Approach by PCR is the Best Method to Detect the Presence of Chlamydia Trachomatis and to Define the True Agent of Ocular Bacterial Inflammation

Abstract

Chlamydia trachomatis (Ct) is an atypical agent for acute, subclinical and chronic conjunctivitis in developed countries, as stated by the International League against Trachoma. In order to evaluate the presence of Ct, from a total of 3,520 patients visiting the consulting room of the Eye Clinic of G. d'Annunzio University of Chieti, Italy from 2006–2008, we enrolled 171 patients affected by occasional mild, moderate or severe conjunctivitis in a three-arm prospective open study, using traditional analysis such as Immune Fluorescent Assay and Enzyme–Linked Fluorescent Assay (IFA and ELFA) and molecular analysis with Polymerase Chain Reaction (PCR) procedure for Ct DNA research (Ct DNA). At the same time, microbiological culture was carried out for common germs and mycetes. These patients were analyzed at different subsequent times. In the first arm (Group A) of 82 patients with IFA and ELFA only 10 people (12.2%) resulted positive to Ct infection with both methods. The presence of Ct was never alone, but always overlapped with contaminants, like corynebacteria, staphylococci, streptococci and colonbacteria, randomly distributed, while no growth of mycetes was observed. Of these positive patients, only one 47-year-old female, suffering from a moderate form of ocular chlamydial infection, showed serological conversion against this infection; furthermore, this female had also been suffering from reactive arthritis for sometime. In the second arm (Group B) of 89 patients, we carried out PCR for Ct detection: 82 (94.25%) were found positive to Ct – DNA research, with common germ growth randomly associated, without sex or age prevalence, as in group A; no mycetes were found. The third arm (Group C) included 37 negative patients from Group A with severe or moderate chronic conjunctivitis, randomly recruited between relapsing cases, with the addition of the single previously positive seroconversion case, for a total of 38 patients, who were re-evaluated by PCR Ct-DNA analysis. All these patients, negative to IFA and ELFA, were positive to Ct-DNA analysis. These data indicate a higher rate of Ct infection in patients with severe or moderate chronic conjunctivitis, resistant to usual therapies even after eradication of common germs, thus showing the advantage of introducing this molecular technique of analysis in mild to severe chronic or recurrent conjunctivitis.