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Abstract Ocular C. trachomatis infections remain one of the leading neglected infectious causes of blindness, that continue to be of public health concern in developing countries. Annually about one million cases reported that could be infected by C. trachomatis according to the CDC. It is endemic in fifty-one countries. Unfortunately, Africa is the worst affected continent: 18 million cases of active trachoma (85% of all cases globally) are thought to exist in 29 of the 47 countries in WHO’s African Region. Active trachoma is characterized by an existence of follicles and inflammation in the upper tarsal conjunctiva. In case of repeated infections, the upper tarsal conjunctiva may become extremely scarred then the eyelashes transform inwards, scratching the eyeball causing corneal opacity and blindness. It is caused by ocular strains (A, B, Ba and C) of C. trachomatis, which is the most prevalent in poor, rural communities with low standards of hygiene and sanitation. There is lack of knowledge about the extent of Chlamydia infection as a leading cause of infectious blindness in Egypt. Mostly the diagnosis of follicular conjunctivitis is based on the clinical point of view with subsequent empirically used antibiotics as a treatment which plays a role in the development of antibiotic resistance. 73 English Summary • However, the follicles are not pathognomonic for trachoma but are reasonably predictive of it when seen in individuals living in communities where trachoma is endemic. There are other causes of follicular conjunctivitis such as viral infections from which the adenovirus is the most prevalent, & toxic conjunctivitis secondary to topical drugs. So, the observation of this clinical sign may not be specific for Chlamydial infection. Moreover, the worldwide increase in the prevalence of Chlamydia infection has generated much interest in the development of sensitive, specific, and rapid techniques for early diagnosis which is mandatory to avoid serious complications. Chlamydial infection was merely diagnosed by clinical presentation and Giemsa stain for its intracytoplasmic inclusion bodies, but patients may present with atypical symptoms. So, its detection is based on isolation on tissue culture media which is tedious and slow. While NAATs are the most sensitive and specific as compared to culture. PCR is the gold standard technique used for diagnosis C. trachomatis infection through DNA amplification. This study aimed to molecularly detect the presence of C. trachomatis 16S rRNA gene in conjunctival samples which was chosen for its specificity and its conserved nature across strains, enabling accurate detection of the pathogen and investigate its association with clinical features and demographic parameters 74 English Summary • in patients complaining of follicular conjunctivitis in an endemic region like Egypt. This was a cross-sectional study conducted at the outpatient ophthalmology clinic at Ain-Shams University Hospitals, Egypt from March to November 2023. Forty patients with range of ages 18 to 64 years, were selected based on clinical presentation with follicular conjunctivitis using established criteria such as characteristic symptoms and signs upon examination. Most of the patients (82.5%) were aged 18- 39 years old with equal distribution between 20 males and 20 females. Their median age was 26 years. Conjunctival scraping samples were collected, and DNA extraction was performed for amplification targeting the 16S rRNA gene of C. trachomatis by conventional PCR in the medical microbiology laboratory at faculty of medicine, Ain Shams University. PCR results revealed thirty samples (75%) tested positive for C. trachomatis, while ten samples (25%) tested negative. A significant association between the median age and C. trachomatis prevalence (P < 0.05) with a higher positivity rate in young adults (76.7%) aged between 18-39 years old was found in the present study. In addition, our study revealed a significant gender-based difference, with females exhibiting a higher prevalence of C. trachomatis compared to males (66.7% versus 33.3% respectively) (P < 0.01). Also, elucidated a highly significant 75 English Summary • correlation between the site of infection and PCR results (P < 0.01). As well, our study established a significant correlation between symptoms and PCR results, reinforcing the clinical relevance of C. trachomatis in follicular conjunctivitis. Symptoms such as redness founds in 39 (97.5%), foreign body sensation in 37 (92.5%), irritation in 37 (92.5%), itching in 36 (90%), tearing in 35 (87.5%), burning sensation in 15 (37.5%), and blurred vision in 10 (25%), were strongly associated with positive PCR results (P < 0.01). |